Virtual private networking (VPN) companies market their services as a way to prevent anyone from snooping on your Internet usage. But new research suggests this is a dangerous assumption when connecting to a VPN via an untrusted network, because attackers on the same network could force a target’s traffic off of the protection provided by their VPN without triggering any alerts to the user.

Image: Shutterstock.

When a device initially tries to connect to a network, it broadcasts a message to the entire local network stating that it is requesting an Internet address. Normally, the only system on the network that notices this request and replies is the router responsible for managing the network to which the user is trying to connect.

The machine on a network responsible for fielding these requests is called a Dynamic Host Configuration Protocol (DHCP) server, which will issue time-based leases for IP addresses. The DHCP server also takes care of setting a specific local address — known as an Internet gateway — that all connecting systems will use as a primary route to the Web.

VPNs work by creating a virtual network interface that serves as an encrypted tunnel for communications. But researchers at Leviathan Security say they’ve discovered it’s possible to abuse an obscure feature built into the DHCP standard so that other users on the local network are forced to connect to a rogue DHCP server.

“Our technique is to run a DHCP server on the same network as a targeted VPN user and to also set our DHCP configuration to use itself as a gateway,” Leviathan researchers Lizzie Moratti and Dani Cronce wrote. “When the traffic hits our gateway, we use traffic forwarding rules on the DHCP server to pass traffic through to a legitimate gateway while we snoop on it.”

The feature being abused here is known as DHCP option 121, and it allows a DHCP server to set a route on the VPN user’s system that is more specific than those used by most VPNs. Abusing this option, Leviathan found, effectively gives an attacker on the local network the ability to set up routing rules that have a higher priority than the routes for the virtual network interface that the target’s VPN creates.

“Pushing a route also means that the network traffic will be sent over the same interface as the DHCP server instead of the virtual network interface,” the Leviathan researchers said. “This is intended functionality that isn’t clearly stated in the RFC [standard]. Therefore, for the routes we push, it is never encrypted by the VPN’s virtual interface but instead transmitted by the network interface that is talking to the DHCP server. As an attacker, we can select which IP addresses go over the tunnel and which addresses go over the network interface talking to our DHCP server.”

Leviathan found they could force VPNs on the local network that already had a connection to arbitrarily request a new one. In this well-documented tactic, known as a DHCP starvation attack, an attacker floods the DHCP server with requests that consume all available IP addresses that can be allocated. Once the network’s legitimate DHCP server is completely tied up, the attacker can then have their rogue DHCP server respond to all pending requests.

“This technique can also be used against an already established VPN connection once the VPN user’s host needs to renew a lease from our DHCP server,” the researchers wrote. “We can artificially create that scenario by setting a short lease time in the DHCP lease, so the user updates their routing table more frequently. In addition, the VPN control channel is still intact because it already uses the physical interface for its communication. In our testing, the VPN always continued to report as connected, and the kill switch was never engaged to drop our VPN connection.”

The researchers say their methods could be used by an attacker who compromises a DHCP server or wireless access point, or by a rogue network administrator who owns the infrastructure themselves and maliciously configures it. Alternatively, an attacker could set up an “evil twin” wireless hotspot that mimics the signal broadcast by a legitimate provider.

ANALYSIS

Bill Woodcock is executive director at Packet Clearing House, a nonprofit based in San Francisco. Woodcock said Option 121 has been included in the DHCP standard since 2002, which means the attack described by Leviathan has technically been possible for the last 22 years.

“They’re realizing now that this can be used to circumvent a VPN in a way that’s really problematic, and they’re right,” Woodcock said.

Woodcock said anyone who might be a target of spear phishing attacks should be very concerned about using VPNs on an untrusted network.

“Anyone who is in a position of authority or maybe even someone who is just a high net worth individual, those are all very reasonable targets of this attack,” he said. “If I were trying to do an attack against someone at a relatively high security company and I knew where they typically get their coffee or sandwich at twice a week, this is a very effective tool in that toolbox. I’d be a little surprised if it wasn’t already being exploited in that way, because again this isn’t rocket science. It’s just thinking a little outside the box.”

Successfully executing this attack on a network likely would not allow an attacker to see all of a target’s traffic or browsing activity. That’s because for the vast majority of the websites visited by the target, the content is encrypted (the site’s address begins with https://). However, an attacker would still be able to see the metadata — such as the source and destination addresses — of any traffic flowing by.

KrebsOnSecurity shared Leviathan’s research with John Kristoff, founder of dataplane.org and a PhD candidate in computer science at the University of Illinois Chicago. Kristoff said practically all user-edge network gear, including WiFi deployments, support some form of rogue DHCP server detection and mitigation, but that it’s unclear how widely deployed those protections are in real-world environments.

“However, and I think this is a key point to emphasize, an untrusted network is an untrusted network, which is why you’re usually employing the VPN in the first place,” Kristoff said. “If [the] local network is inherently hostile and has no qualms about operating a rogue DHCP server, then this is a sneaky technique that could be used to de-cloak some traffic – and if done carefully, I’m sure a user might never notice.”

MITIGATIONS

According to Leviathan, there are several ways to minimize the threat from rogue DHCP servers on an unsecured network. One is using a device powered by the Android operating system, which apparently ignores DHCP option 121.

Relying on a temporary wireless hotspot controlled by a cellular device you own also effectively blocks this attack.

“They create a password-locked LAN with automatic network address translation,” the researchers wrote of cellular hot-spots. “Because this network is completely controlled by the cellular device and requires a password, an attacker should not have local network access.”

Leviathan’s Moratti said another mitigation is to run your VPN from inside of a virtual machine (VM) — like Parallels, VMware or VirtualBox. VPNs run inside of a VM are not vulnerable to this attack, Moratti said, provided they are not run in “bridged mode,” which causes the VM to replicate another node on the network.

In addition, a technology called “deep packet inspection” can be used to deny all in- and outbound traffic from the physical interface except for the DHCP and the VPN server. However, Leviathan says this approach opens up a potential “side channel” attack that could be used to determine the destination of traffic.

“This could be theoretically done by performing traffic analysis on the volume a target user sends when the attacker’s routes are installed compared to the baseline,” they wrote. “In addition, this selective denial-of-service is unique as it could be used to censor specific resources that an attacker doesn’t want a target user to connect to even while they are using the VPN.”

Moratti said Leviathan’s research shows that many VPN providers are currently making promises to their customers that their technology can’t keep.

“VPNs weren’t designed to keep you more secure on your local network, but to keep your traffic more secure on the Internet,” Moratti said. “When you start making assurances that your product protects people from seeing your traffic, there’s an assurance or promise that can’t be met.”

A copy of Leviathan’s research, along with code intended to allow others to duplicate their findings in a lab environment, is available here.

The U.S. government is warning that “smart locks” securing entry to an estimated 50,000 dwellings nationwide contain hard-coded credentials that can be used to remotely open any of the locks. The lock’s maker Chirp Systems remains unresponsive, even though it was first notified about the critical weakness in March 2021. Meanwhile, Chirp’s parent company, RealPage, Inc., is being sued by multiple U.S. states for allegedly colluding with landlords to illegally raise rents.

On March 7, 2024, the U.S. Cybersecurity & Infrastructure Security Agency (CISA) warned about a remotely exploitable vulnerability with “low attack complexity” in Chirp Systems smart locks.

“Chirp Access improperly stores credentials within its source code, potentially exposing sensitive information to unauthorized access,” CISA’s alert warned, assigning the bug a CVSS (badness) rating of 9.1 (out of a possible 10). “Chirp Systems has not responded to requests to work with CISA to mitigate this vulnerability.”

Matt Brown, the researcher CISA credits with reporting the flaw, is a senior systems development engineer at Amazon Web Services. Brown said he discovered the weakness and reported it to Chirp in March 2021, after the company that manages his apartment building started using Chirp smart locks and told everyone to install Chirp’s app to get in and out of their apartments.

“I use Android, which has a pretty simple workflow for downloading and decompiling the APK apps,” Brown told KrebsOnSecurity. “Given that I am pretty picky about what I trust on my devices, I downloaded Chirp and after decompiling, found that they were storing passwords and private key strings in a file.”

Using those hard-coded credentials, Brown found an attacker could then connect to an application programming interface (API) that Chirp uses which is managed by smart lock vendor August.com, and use that to enumerate and remotely lock or unlock any door in any building that uses the technology.

Update, April 18, 11:55 a.m. ET: August has provided a statement saying it does not believe August or Yale locks are vulnerable to the hack described by Brown.

“We were recently made aware of a vulnerability disclosure regarding access control systems provided by Chirp, using August and Yale locks in multifamily housing,” the company said. “Upon learning of these reports, we immediately and thoroughly investigated these claims. Our investigation found no evidence that would substantiate the vulnerability claims in either our product or Chirp’s as it relates to our systems.”

Update, April 25, 2:45 p.m. ET: Based on feedback from Chirp, CISA has downgraded the severity of this flaw and revised their security advisory to say that the hard-coded credentials do not appear to expose the devices to remote locking or unlocking. CISA says the hardcoded credentials could be used by an attacker within the range of Bluetooth (~30 meters) “to change the configuration settings within the Bluetooth beacon, effectively removing Bluetooth visibility from the device. This does not affect the device’s ability to lock or unlock access points, and access points can still be operated remotely by unauthorized users via other means.”

Brown said when he complained to his leasing office, they sold him a small $50 key fob that uses Near-Field Communications (NFC) to toggle the lock when he brings the fob close to his front door. But he said the fob doesn’t eliminate the ability for anyone to remotely unlock his front door using the exposed credentials and the Chirp mobile app.

Also, the fobs pass the credentials to his front door over the air in plain text, meaning someone could clone the fob just by bumping against him with a smartphone app made to read and write NFC tags.

Neither August nor Chirp Systems responded to requests for comment. It’s unclear exactly how many apartments and other residences are using the vulnerable Chirp locks, but multiple articles about the company from 2020 state that approximately 50,000 units use Chirp smart locks with August’s API.

Roughly a year before Brown reported the flaw to Chirp Systems, the company was bought by RealPage, a firm founded in 1998 as a developer of multifamily property management and data analytics software. In 2021, RealPage was acquired by the private equity giant Thoma Bravo.

Brown said the exposure he found in Chirp’s products is “an obvious flaw that is super easy to fix.”

“It’s just a matter of them being motivated to do it,” he said. “But they’re part of a private equity company now, so they’re not answerable to anybody. It’s too bad, because it’s not like residents of [the affected] properties have another choice. It’s either agree to use the app or move.”

In October 2022, an investigation by ProPublica examined RealPage’s dominance in the rent-setting software market, and that it found “uses a mysterious algorithm to help landlords push the highest possible rents on tenants.”

“For tenants, the system upends the practice of negotiating with apartment building staff,” ProPublica found. “RealPage discourages bargaining with renters and has even recommended that landlords in some cases accept a lower occupancy rate in order to raise rents and make more money. One of the algorithm’s developers told ProPublica that leasing agents had ‘too much empathy’ compared to computer generated pricing.”

Last year, the U.S. Department of Justice threw its weight behind a massive lawsuit filed by dozens of tenants who are accusing the $9 billion apartment software company of helping landlords collude to inflate rents.

In February 2024, attorneys general for Arizona and the District of Columbia sued RealPage, alleging RealPage’s software helped create a rental monopoly.

A cybercrook who has been setting up websites that mimic the self-destructing message service privnote.com accidentally exposed the breadth of their operations recently when they threatened to sue a software company. The disclosure revealed a profitable network of phishing sites that behave and look like the real Privnote, except that any messages containing cryptocurrency addresses will be automatically altered to include a different payment address controlled by the scammers.

The real Privnote, at privnote.com.

Launched in 2008, privnote.com employs technology that encrypts each message so that even Privnote itself cannot read its contents. And it doesn’t send or receive messages. Creating a message merely generates a link. When that link is clicked or visited, the service warns that the message will be gone forever after it is read.

Privnote’s ease-of-use and popularity among cryptocurrency enthusiasts has made it a perennial target of phishers, who erect Privnote clones that function more or less as advertised but also quietly inject their own cryptocurrency payment addresses when a note is created that contains crypto wallets.

Last month, a new user on GitHub named fory66399 lodged a complaint on the “issues” page for MetaMask, a software cryptocurrency wallet used to interact with the Ethereum blockchain. Fory66399 insisted that their website — privnote[.]co — was being wrongly flagged by MetaMask’s “eth-phishing-detect” list as malicious.

“We filed a lawsuit with a lawyer for dishonestly adding a site to the block list, damaging reputation, as well as ignoring the moderation department and ignoring answers!” fory66399 threatened. “Provide evidence or I will demand compensation!”

MetaMask’s lead product manager Taylor Monahan replied by posting several screenshots of privnote[.]co showing the site did indeed swap out any cryptocurrency addresses.

After being told where they could send a copy of their lawsuit, Fory66399 appeared to become flustered, and proceeded to mention a number of other interesting domain names:

You sent me screenshots from some other site! It’s red!!!!
The tornote.io website has a different color altogether
The privatenote,io website also has a different color! What’s wrong?????

A search at DomainTools.com for privatenote[.]io shows it has been registered to two names over as many years, including Andrey Sokol from Moscow and Alexandr Ermakov from Kiev. There is no indication these are the real names of the phishers, but the names are useful in pointing to other sites targeting Privnote since 2020.

DomainTools says other domains registered to Alexandr Ermakov include pirvnota[.]com, privatemessage[.]net, privatenote[.]io, and tornote[.]io.

A screenshot of the phishing domain privatemessage dot net.

The registration records for pirvnota[.]com at one point were updated from Andrey Sokol to “BPW” as the registrant organization, and “Tambov district” in the registrant state/province field. Searching DomainTools for domains that include both of these terms reveals pirwnote[.]com.

Other Privnote phishing domains that also phoned home to the same Internet address as pirwnote[.]com include privnode[.]com, privnate[.]com, and prevnóte[.]com. Pirwnote[.]com is currently selling security cameras made by the Chinese manufacturer Hikvision, via an Internet address based in Hong Kong.

It appears someone has gone to great lengths to make tornote[.]io seem like a legitimate website. For example, this account at Medium has authored more than a dozen blog posts in the past year singing the praises of Tornote as a secure, self-destructing messaging service. However, testing shows tornote[.]io will also replace any cryptocurrency addresses in messages with their own payment address.

These malicious note sites attract visitors by gaming search engine results to make the phishing domains appear prominently in search results for “privnote.” A search in Google for “privnote” currently returns tornote[.]io as the fifth result. Like other phishing sites tied to this network, Tornote will use the same cryptocurrency addresses for roughly 5 days, and then rotate in new payment addresses.

Tornote changed the cryptocurrency address entered into a test note to this address controlled by the phishers.

Throughout 2023, Tornote was hosted with the Russian provider DDoS-Guard, at the Internet address 186.2.163[.]216. A review of the passive DNS records tied to this address shows that apart from subdomains dedicated to tornote[.]io, the main other domain at this address was hkleaks[.]ml.

In August 2019, a slew of websites and social media channels dubbed “HKLEAKS” began doxing the identities and personal information of pro-democracy activists in Hong Kong. According to a report (PDF) from Citizen Lab, hkleaks[.]ml was the second domain that appeared as the perpetrators began to expand the list of those doxed.

HKleaks, as indexed by The Wayback Machine.

DomainTools shows there are more than 1,000 other domains whose registration records include the organization name “BPW” and “Tambov District” as the location. Virtually all of those domains were registered through one of two registrars — Hong Kong-based Nicenic and Singapore-based WebCC — and almost all appear to be phishing or pill-spam related.

Among those is rustraitor[.]info, a website erected after Russia invaded Ukraine in early 2022 that doxed Russians perceived to have helped the Ukrainian cause.

An archive.org copy of Rustraitor.

In keeping with the overall theme, these phishing domains appear focused on stealing usernames and passwords to some of the cybercrime underground’s busiest shops, including Brian’s Club. What do all the phished sites have in common? They all accept payment via virtual currencies.

It appears MetaMask’s Monahan made the correct decision in forcing these phishers to tip their hand: Among the websites at that DDoS-Guard address are multiple MetaMask phishing domains, including metarrnask[.]com, meternask[.]com, and rnetamask[.]com.

How profitable are these private note phishing sites? Reviewing the four malicious cryptocurrency payment addresses that the attackers swapped into notes passed through privnote[.]co (as pictured in Monahan’s screenshot above) shows that between March 15 and March 19, 2024, those address raked in and transferred out nearly $18,000 in cryptocurrencies. And that’s just one of their phishing websites.

Thread hijacking attacks. They happen when someone you know has their email account compromised, and you are suddenly dropped into an existing conversation between the sender and someone else. These missives draw on the recipient’s natural curiosity about being copied on a private discussion, which is modified to include a malicious link or attachment. Here’s the story of a thread hijacking attack in which a journalist was copied on a phishing email from the unwilling subject of a recent scoop.

In Sept. 2023, the Pennsylvania news outlet LancasterOnline.com published a story about Adam Kidan, a wealthy businessman with a criminal past who is a major donor to Republican causes and candidates, including Rep. Lloyd Smucker (R-Pa).

The LancasterOnline story about Adam Kidan.

Several months after that piece ran, the story’s author Brett Sholtis received two emails from Kidan, both of which contained attachments. One of the messages appeared to be a lengthy conversation between Kidan and a colleague, with the subject line, “Re: Successfully sent data.” The second missive was a more brief email from Kidan with the subject, “Acknowledge New Work Order,” and a message that read simply, “Please find the attached.”

Sholtis said he clicked the attachment in one of the messages, which then launched a web page that looked exactly like a Microsoft Office 365 login page. An analysis of the webpage reveals it would check any submitted credentials at the real Microsoft website, and return an error if the user entered bogus account information. A successful login would record the submitted credentials and forward the victim to the real Microsoft website.

But Sholtis said he didn’t enter his Outlook username and password. Instead, he forwarded the messages to LancasterOneline’s IT team, which quickly flagged them as phishing attempts.

LancasterOnline Executive Editor Tom Murse said the two phishing messages from Mr. Kidan raised eyebrows in the newsroom because Kidan had threatened to sue the news outlet multiple times over Sholtis’s story.

“We were just perplexed,” Murse said. “It seemed to be a phishing attempt but we were confused why it would come from a prominent businessman we’ve written about. Our initial response was confusion, but we didn’t know what else to do with it other than to send it to the FBI.”

The phishing lure attached to the thread hijacking email from Mr. Kidan.

In 2006, Kidan was sentenced to 70 months in federal prison after pleading guilty to defrauding lenders along with Jack Abramoff, the disgraced lobbyist whose corruption became a symbol of the excesses of Washington influence peddling. He was paroled in 2009, and in 2014 moved his family to a home in Lancaster County, Pa.

The FBI hasn’t responded to LancasterOnline’s tip. Messages sent by KrebsOnSecurity to Kidan’s emails addresses were returned as blocked. Messages left with Mr. Kidan’s company, Empire Workforce Solutions, went unreturned.

No doubt the FBI saw the messages from Kidan for what they likely were: The result of Mr. Kidan having his Microsoft Outlook account compromised and used to send malicious email to people in his contacts list.

Thread hijacking attacks are hardly new, but that is mainly true because many Internet users still don’t know how to identify them. The email security firm Proofpoint says it has tracked north of 90 million malicious messages in the last five years that leverage this attack method.

One key reason thread hijacking is so successful is that these attacks generally do not include the tell that exposes most phishing scams: A fabricated sense of urgency. A majority of phishing threats warn of negative consequences should you fail to act quickly — such as an account suspension or an unauthorized high-dollar charge going through.

In contrast, thread hijacking campaigns tend to patiently prey on the natural curiosity of the recipient.

Ryan Kalember, chief strategy officer at Proofpoint, said probably the most ubiquitous examples of thread hijacking are “CEO fraud” or “business email compromise” scams, wherein employees are tricked by an email from a senior executive into wiring millions of dollars to fraudsters overseas.

But Kalember said these low-tech attacks can nevertheless be quite effective because they tend to catch people off-guard.

“It works because you feel like you’re suddenly included in an important conversation,” Kalember said. “It just registers a lot differently when people start reading, because you think you’re observing a private conversation between two different people.”

Some thread hijacking attacks actually involve multiple threat actors who are actively conversing while copying — but not addressing — the recipient.

“We call these multi-persona phishing scams, and they’re often paired with thread hijacking,” Kalember said. “It’s basically a way to build a little more affinity than just copying people on an email. And the longer the conversation goes on, the higher their success rate seems to be because some people start replying to the thread [and participating] psycho-socially.”

The best advice to sidestep phishing scams is to avoid clicking on links or attachments that arrive unbidden in emails, text messages and other mediums. If you’re unsure whether the message is legitimate, take a deep breath and visit the site or service in question manually — ideally, using a browser bookmark so as to avoid potential typosquatting sites.

Several Apple customers recently reported being targeted in elaborate phishing attacks that involve what appears to be a bug in Apple’s password reset feature. In this scenario, a target’s Apple devices are forced to display dozens of system-level prompts that prevent the devices from being used until the recipient responds “Allow” or “Don’t Allow” to each prompt. Assuming the user manages not to fat-finger the wrong button on the umpteenth password reset request, the scammers will then call the victim while spoofing Apple support in the caller ID, saying the user’s account is under attack and that Apple support needs to “verify” a one-time code.

Some of the many notifications Patel says he received from Apple all at once.

Parth Patel is an entrepreneur who is trying to build a startup in the conversational AI space. On March 23, Patel documented on Twitter/X a recent phishing campaign targeting him that involved what’s known as a “push bombing” or “MFA fatigue” attack, wherein the phishers abuse a feature or weakness of a multi-factor authentication (MFA) system in a way that inundates the target’s device(s) with alerts to approve a password change or login.

“All of my devices started blowing up, my watch, laptop and phone,” Patel told KrebsOnSecurity. “It was like this system notification from Apple to approve [a reset of the account password], but I couldn’t do anything else with my phone. I had to go through and decline like 100-plus notifications.”

Some people confronted with such a deluge may eventually click “Allow” to the incessant password reset prompts — just so they can use their phone again. Others may inadvertently approve one of these prompts, which will also appear on a user’s Apple watch if they have one.

But the attackers in this campaign had an ace up their sleeves: Patel said after denying all of the password reset prompts from Apple, he received a call on his iPhone that said it was from Apple Support (the number displayed was 1-800-275-2273, Apple’s real customer support line).

“I pick up the phone and I’m super suspicious,” Patel recalled. “So I ask them if they can verify some information about me, and after hearing some aggressive typing on his end he gives me all this information about me and it’s totally accurate.”

All of it, that is, except his real name. Patel said when he asked the fake Apple support rep to validate the name they had on file for the Apple account, the caller gave a name that was not his but rather one that Patel has only seen in background reports about him that are for sale at a people-search website called PeopleDataLabs.

Patel said he has worked fairly hard to remove his information from multiple people-search websites, and he found PeopleDataLabs uniquely and consistently listed this inaccurate name as an alias on his consumer profile.

“For some reason, PeopleDataLabs has three profiles that come up when you search for my info, and two of them are mine but one is an elementary school teacher from the midwest,” Patel said. “I asked them to verify my name and they said Anthony.”

Patel said the goal of the voice phishers is to trigger an Apple ID reset code to be sent to the user’s device, which is a text message that includes a one-time password. If the user supplies that one-time code, the attackers can then reset the password on the account and lock the user out. They can also then remotely wipe all of the user’s Apple devices.

THE PHONE NUMBER IS KEY

Chris is a cryptocurrency hedge fund owner who asked that only his first name be used so as not to paint a bigger target on himself. Chris told KrebsOnSecurity he experienced a remarkably similar phishing attempt in late February.

“The first alert I got I hit ‘Don’t Allow’, but then right after that I got like 30 more notifications in a row,” Chris said. “I figured maybe I sat on my phone weird, or was accidentally pushing some button that was causing these, and so I just denied them all.”

Chris says the attackers persisted hitting his devices with the reset notifications for several days after that, and at one point he received a call on his iPhone that said it was from Apple support.

“I said I would call them back and hung up,” Chris said, demonstrating the proper response to such unbidden solicitations. “When I called back to the real Apple, they couldn’t say whether anyone had been in a support call with me just then. They just said Apple states very clearly that it will never initiate outbound calls to customers — unless the customer requests to be contacted.”

Massively freaking out that someone was trying to hijack his digital life, Chris said he changed his passwords and then went to an Apple store and bought a new iPhone. From there, he created a new Apple iCloud account using a brand new email address.

Chris said he then proceeded to get even more system alerts on his new iPhone and iCloud account — all the while still sitting at the local Apple Genius Bar.

Chris told KrebsOnSecurity his Genius Bar tech was mystified about the source of the alerts, but Chris said he suspects that whatever the phishers are abusing to rapidly generate these Apple system alerts requires knowing the phone number on file for the target’s Apple account. After all, that was the only aspect of Chris’s new iPhone and iCloud account that hadn’t changed.

WATCH OUT!

“Ken” is a security industry veteran who spoke on condition of anonymity. Ken said he first began receiving these unsolicited system alerts on his Apple devices earlier this year, but that he has not received any phony Apple support calls as others have reported.

“This recently happened to me in the middle of the night at 12:30 a.m.,” Ken said. “And even though I have my Apple watch set to remain quiet during the time I’m usually sleeping at night, it woke me up with one of these alerts. Thank god I didn’t press ‘Allow,’ which was the first option shown on my watch. I had to scroll watch the wheel to see and press the ‘Don’t Allow’ button.”

Ken shared this photo he took of an alert on his watch that woke him up at 12:30 a.m. Ken said he had to scroll on the watch face to see the “Don’t Allow” button.

Ken didn’t know it when all this was happening (and it’s not at all obvious from the Apple prompts), but clicking “Allow” would not have allowed the attackers to change Ken’s password. Rather, clicking “Allow” displays a six digit PIN that must be entered on Ken’s device — allowing Ken to change his password. It appears that these rapid password reset prompts are being used to make a subsequent inbound phone call spoofing Apple more believable.

Ken said he contacted the real Apple support and was eventually escalated to a senior Apple engineer. The engineer assured Ken that turning on an Apple Recovery Key for his account would stop the notifications once and for all.

A recovery key is an optional security feature that Apple says “helps improve the security of your Apple ID account.” It is a randomly generated 28-character code, and when you enable a recovery key it is supposed to disable Apple’s standard account recovery process. The thing is, enabling it is not a simple process, and if you ever lose that code in addition to all of your Apple devices you will be permanently locked out.

Ken said he enabled a recovery key for his account as instructed, but that it hasn’t stopped the unbidden system alerts from appearing on all of his devices every few days.

KrebsOnSecurity tested Ken’s experience, and can confirm that enabling a recovery key does nothing to stop a password reset prompt from being sent to associated Apple devices. Visiting Apple’s “forgot password” page — https://iforgot.apple.com — asks for an email address and for the visitor to solve a CAPTCHA.

After that, the page will display the last two digits of the phone number tied to the Apple account. Filling in the missing digits and hitting submit on that form will send a system alert, whether or not the user has enabled an Apple Recovery Key.

The password reset page at iforgot.apple.com.

RATE LIMITS

What sanely designed authentication system would send dozens of requests for a password change in the span of a few moments, when the first requests haven’t even been acted on by the user? Could this be the result of a bug in Apple’s systems?

Apple has not yet responded to requests for comment.

Throughout 2022, a criminal hacking group known as LAPSUS$ used MFA bombing to great effect in intrusions at Cisco, Microsoft and Uber. In response, Microsoft began enforcing “MFA number matching,” a feature that displays a series of numbers to a user attempting to log in with their credentials. These numbers must then be entered into the account owner’s Microsoft authenticator app on their mobile device to verify they are logging into the account.

Kishan Bagaria is a hobbyist security researcher and engineer who founded the website texts.com (now owned by Automattic), and he’s convinced Apple has a problem on its end. In August 2019, Bagaria reported to Apple a bug that allowed an exploit he dubbed “AirDoS” because it could be used to let an attacker infinitely spam all nearby iOS devices with a system-level prompt to share a file via AirDrop — a file-sharing capability built into Apple products.

Apple fixed that bug nearly four months later in December 2019, thanking Bagaria in the associated security bulletin. Bagaria said Apple’s fix was to add stricter rate limiting on AirDrop requests, and he suspects that someone has figured out a way to bypass Apple’s rate limit on how many of these password reset requests can be sent in a given timeframe.

“I think this could be a legit Apple rate limit bug that should be reported,” Bagaria said.

WHAT CAN YOU DO?

Apple seems requires a phone number to be on file for your account, but after you’ve set up the account it doesn’t have to be a mobile phone number. KrebsOnSecurity’s testing shows Apple will accept a VOIP number (like Google Voice). So, changing your account phone number to a VOIP number that isn’t widely known would be one mitigation here.

One caveat with the VOIP number idea: Unless you include a real mobile number, Apple’s iMessage and Facetime applications will be disabled for that device. This might a bonus for those concerned about reducing the overall attack surface of their Apple devices, since zero-click zero-days in these applications have repeatedly been used by spyware purveyors.

Also, it appears Apple’s password reset system will accept and respect email aliases. Adding a “+” character after the username portion of your email address — followed by a notation specific to the site you’re signing up at — lets you create an infinite number of unique email addresses tied to the same account.

For instance, if I were signing up at example.com, I might give my email address as krebsonsecurity+example@gmail.com. Then, I simply go back to my inbox and create a corresponding folder called “Example,” along with a new filter that sends any email addressed to that alias to the Example folder. In this case, however, perhaps a less obvious alias than “+apple” would be advisable.

Update, March 27, 5:06 p.m. ET: Added perspective on Ken’s experience. Also included a What Can You Do? section.

Malicious hackers are targeting people in the cryptocurrency space in attacks that start with a link added to the target’s calendar at Calendly, a popular application for scheduling appointments and meetings. The attackers impersonate established cryptocurrency investors and ask to schedule a video conference call. But clicking the meeting link provided by the scammers prompts the user to run a script that quietly installs malware on macOS systems.

KrebsOnSecurity recently heard from a reader who works at a startup that is seeking investment for building a new blockchain platform for the Web. The reader spoke on condition that their name not be used in this story, so for the sake of simplicity we’ll call him Doug.

Being in the cryptocurrency scene, Doug is also active on the instant messenger platform Telegram. Earlier this month, Doug was approached by someone on Telegram whose profile name, image and description said they were Ian Lee, from Signum Capital, a well-established investment firm based in Singapore. The profile also linked to Mr. Lee’s Twitter/X account, which features the same profile image.

The investor expressed interest in financially supporting Doug’s startup, and asked if Doug could find time for a video call to discuss investment prospects. Sure, Doug said, here’s my Calendly profile, book a time and we’ll do it then.

When the day and time of the scheduled meeting with Mr. Lee arrived, Doug clicked the meeting link in his calendar but nothing happened. Doug then messaged the Mr. Lee account on Telegram, who said there was some kind of technology issue with the video platform, and that their IT people suggested using a different meeting link.

Doug clicked the new link, but instead of opening up a videoconference app, a message appeared on his Mac saying the video service was experiencing technical difficulties.

“Some of our users are facing issues with our service,” the message read. “We are actively working on fixing these problems. Please refer to this script as a temporary solution.”

Doug said he ran the script, but nothing appeared to happen after that, and the videoconference application still wouldn’t start. Mr. Lee apologized for the inconvenience and said they would have to reschedule their meeting, but he never responded to any of Doug’s follow-up messages.

It didn’t dawn on Doug until days later that the missed meeting with Mr. Lee might have been a malware attack. Going back to his Telegram client to revisit the conversation, Doug discovered his potential investor had deleted the meeting link and other bits of conversation from their shared chat history.

In a post to its Twitter/X account last month, Signum Capital warned that a fake profile pretending to be their employee Mr. Lee was trying to scam people on Telegram.

The file that Doug ran is a simple Apple Script (file extension “.scpt”) that downloads and executes a malicious trojan made to run on macOS systems. Unfortunately for us, Doug freaked out after deciding he’d been tricked — backing up his important documents, changing his passwords, and then reinstalling macOS on his computer. While this a perfectly sane response, it means we don’t have the actual malware that was pushed to his Mac by the script.

But Doug does still have a copy of the malicious script that was downloaded from clicking the meeting link (the online host serving that link is now offline). A search in Google for a string of text from that script turns up a December 2023 blog post from cryptocurrency security firm SlowMist about phishing attacks on Telegram from North Korean state-sponsored hackers.

“When the project team clicks the link, they encounter a region access restriction,” SlowMist wrote. “At this point, the North Korean hackers coax the team into downloading and running a ‘location-modifying’ malicious script. Once the project team complies, their computer comes under the control of the hackers, leading to the theft of funds.”

Image: SlowMist.

SlowMist says the North Korean phishing scams used the “Add Custom Link” feature of the Calendly meeting scheduling system on event pages to insert malicious links and initiate phishing attacks.

“Since Calendly integrates well with the daily work routines of most project teams, these malicious links do not easily raise suspicion,” the blog post explains. “Consequently, the project teams may inadvertently click on these malicious links, download, and execute malicious code.”

SlowMist said the malware downloaded by the malicious link in their case comes from a North Korean hacking group dubbed “BlueNoroff, which Kaspersky Labs says is a subgroup of the Lazarus hacking group.

“A financially motivated threat actor closely connected with Lazarus that targets banks, casinos, fin-tech companies, POST software and cryptocurrency businesses, and ATMs,” Kaspersky wrote of BlueNoroff in Dec. 2023.

The North Korean regime is known to use stolen cryptocurrencies to fund its military and other state projects. A recent report from Recorded Future finds the Lazarus Group has stolen approximately $3 billion in cryptocurrency over the past six years.

While there is still far more malware out there today targeting Microsoft Windows PCs, the prevalence of information-stealing trojans aimed at macOS users is growing at a steady clip. MacOS computers include X-Protect, Apple’s built-in antivirus technology. But experts say attackers are constantly changing the appearance and behavior of their malware to evade X-Protect.

“Recent updates to macOS’s XProtect signature database indicate that Apple are aware of the problem, but early 2024 has already seen a number of stealer families evade known signatures,” security firm SentinelOne wrote in January.

According to Chris Ueland from the threat hunting platform Hunt.io, the Internet address of the fake meeting website Doug was tricked into visiting (104.168.163,149) hosts or very recently hosted about 75 different domain names, many of which invoke words associated with videoconferencing or cryptocurrency. Those domains indicate this North Korean hacking group is hiding behind a number of phony crypto firms, like the six-month-old website for Cryptowave Capital (cryptowave[.]capital).

In a statement shared with KrebsOnSecurity, Calendly said it was aware of these types of social engineering attacks by cryptocurrency hackers.

“To help prevent these kinds of attacks, our security team and partners have implemented a service to automatically detect fraud and impersonations that could lead to social engineering,” the company said. “We are also actively scanning content for all our customers to catch these types of malicious links and to prevent hackers earlier on. Additionally, we intend to add an interstitial page warning users before they’re redirected away from Calendly to other websites. Along with the steps we’ve taken, we recommend users stay vigilant by keeping their software secure with running the latest updates and verifying suspicious links through tools like VirusTotal to alert them of possible malware. We are continuously strengthening the cybersecurity of our platform to protect our customers.”

The increasing frequency of new Mac malware is a good reminder that Mac users should not depend on security software and tools to flag malicious files, which are frequently bundled with or disguised as legitimate software.

As KrebsOnSecurity has advised Windows users for years, a good rule of safety to live by is this: If you didn’t go looking for it, don’t install it. Following this mantra heads off a great deal of malware attacks, regardless of the platform used. When you do decide to install a piece of software, make sure you are downloading it from the original source, and then keep it updated with any new security fixes.

On that last front, I’ve found it’s a good idea not to wait until the last minute to configure my system before joining a scheduled videoconference call. Even if the call uses software that is already on my computer, it is often the case that software updates are required before the program can be used, and I’m one of those weird people who likes to review any changes to the software maker’s privacy policies or user agreements before choosing to install updates.

Most of all, verify new contacts from strangers before accepting anything from them. In this case, had Doug simply messaged Mr. Lee’s real account on Twitter/X or contacted Signum Capital directly, he would discovered that the real Mr. Lee never asked for a meeting.

If you’re approached in a similar scheme, the response from the would-be victim documented in the SlowMist blog post is probably the best.

Image: SlowMist.

Update: Added comment from Calendly.

The Minnesota-based Internet provider U.S. Internet Corp. has a business unit called Securence, which specializes in providing filtered, secure email services to businesses, educational institutions and government agencies worldwide. But until it was notified last week, U.S. Internet was publishing more than a decade’s worth of its internal email — and that of thousands of Securence clients — in plain text out on the Internet and just a click away for anyone with a Web browser.

Headquartered in Minnetonka, Minn., U.S. Internet is a regional ISP that provides fiber and wireless Internet service. The ISP’s Securence division bills itself “a leading provider of email filtering and management software that includes email protection and security services for small business, enterprise, educational and government institutions worldwide.”

U.S. Internet/Securence says your email is secure. Nothing could be further from the truth.

Roughly a week ago, KrebsOnSecurity was contacted by Hold Security, a Milwaukee-based cybersecurity firm. Hold Security founder Alex Holden said his researchers had unearthed a public link to a U.S. Internet email server listing more than 6,500 domain names, each with its own clickable link.

A tiny portion of the more than 6,500 customers who trusted U.S. Internet with their email.

Drilling down into those individual domain links revealed inboxes for each employee or user of these exposed host names. Some of the emails dated back to 2008; others were as recent as the present day.

Securence counts among its customers dozens of state and local governments, including: nc.gov — the official website of North Carolina; stillwatermn.gov, the website for the city of Stillwater, Minn.; and cityoffrederickmd.gov, the website for the government of Frederick, Md.

Incredibly, included in this giant index of U.S. Internet customer emails were the internal messages for every current and former employee of U.S. Internet and its subsidiary USI Wireless. Since that index also included the messages of U.S. Internet’s CEO Travis Carter, KrebsOnSecurity forwarded one of Mr. Carter’s own recent emails to him, along with a request to understand how exactly the company managed to screw things up so spectacularly.

Individual inboxes of U.S. Wireless employees were published in clear text on the Internet.

Within minutes of that notification, U.S. Internet pulled all of the published inboxes offline. Mr. Carter responded and said his team was investigating how it happened. In the same breath, the CEO asked if KrebsOnSecurity does security consulting for hire (I do not).

[Author’s note: Perhaps Mr. Carter was frantically casting about for any expertise he could find in a tough moment. But I found the request personally offensive, because I couldn’t shake the notion that maybe the company was hoping it could buy my silence.]

Earlier this week, Mr. Carter replied with a highly technical explanation that ultimately did little to explain why or how so many internal and customer inboxes were published in plain text on the Internet.

“The feedback from my team was a issue with the Ansible playbook that controls the Nginx configuration for our IMAP servers,” Carter said, noting that this incorrect configuration was put in place by a former employee and never caught. U.S. Internet has not shared how long these messages were exposed.

“The rest of the platform and other backend services are being audited to verify the Ansible playbooks are correct,” Carter said.

Holden said he also discovered that hackers have been abusing a Securence link scrubbing and anti-spam service called Url-Shield to create links that look benign but instead redirect visitors to hacked and malicious websites.

“The bad guys modify the malicious link reporting into redirects to their own malicious sites,” Holden said. “That’s how the bad guys drive traffic to their sites and increase search engine rankings.”

For example, clicking the Securence link shown in the screenshot directly above leads one to a website that tries to trick visitors into allowing site notifications by couching the request as a CAPTCHA request designed to separate humans from bots. After approving the deceptive CAPTCHA/notification request, the link forwards the visitor to a Russian internationalized domain name (рпроаг[.]рф).

The link to this malicious and deceptive website was created using Securence’s link-scrubbing service. Notification pop-ups were blocked when this site tried to disguise a prompt for accepting notifications as a form of CAPTCHA.

U.S. Internet has not responded to questions about how long it has been exposing all of its internal and customer emails, or when the errant configuration changes were made. The company also still has not disclosed the incident on its website. The last press release on the site dates back to March 2020.

KrebsOnSecurity has been writing about data breaches for nearly two decades, but this one easily takes the cake in terms of the level of incompetence needed to make such a huge mistake unnoticed. I’m not sure what the proper response from authorities or regulators should be to this incident, but it’s clear that U.S. Internet should not be allowed to manage anyone’s email unless and until it can demonstrate more transparency, and prove that it has radically revamped its security.

Microsoft Corp. today pushed software updates to plug more than 70 security holes in its Windows operating systems and related products, including two zero-day vulnerabilities that are already being exploited in active attacks.

Top of the heap on this Fat Patch Tuesday is CVE-2024-21412, a “security feature bypass” in the way Windows handles Internet Shortcut Files that Microsoft says is being targeted in active exploits. Redmond’s advisory for this bug says an attacker would need to convince or trick a user into opening a malicious shortcut file.

Researchers at Trend Micro have tied the ongoing exploitation of CVE-2024-21412 to an advanced persistent threat group dubbed “Water Hydra,” which they say has being using the vulnerability to execute a malicious Microsoft Installer File (.msi) that in turn unloads a remote access trojan (RAT) onto infected Windows systems.

The other zero-day flaw is CVE-2024-21351, another security feature bypass — this one in the built-in Windows SmartScreen component that tries to screen out potentially malicious files downloaded from the Web. Kevin Breen at Immersive Labs says it’s important to note that this vulnerability alone is not enough for an attacker to compromise a user’s workstation, and instead would likely be used in conjunction with something like a spear phishing attack that delivers a malicious file.

Satnam Narang, senior staff research engineer at Tenable, said this is the fifth vulnerability in Windows SmartScreen patched since 2022 and all five have been exploited in the wild as zero-days. They include CVE-2022-44698 in December 2022, CVE-2023-24880 in March 2023, CVE-2023-32049 in July 2023 and CVE-2023-36025 in November 2023.

Narang called special attention to CVE-2024-21410, an “elevation of privilege” bug in Microsoft Exchange Server that Microsoft says is likely to be exploited by attackers. Attacks on this flaw would lead to the disclosure of NTLM hashes, which could be leveraged as part of an NTLM relay or “pass the hash” attack, which lets an attacker masquerade as a legitimate user without ever having to log in.

“We know that flaws that can disclose sensitive information like NTLM hashes are very valuable to attackers,” Narang said. “A Russian-based threat actor leveraged a similar vulnerability to carry out attacks – CVE-2023-23397 is an Elevation of Privilege vulnerability in Microsoft Outlook patched in March 2023.”

Microsoft notes that prior to its Exchange Server 2019 Cumulative Update 14 (CU14), a security feature called Extended Protection for Authentication (EPA), which provides NTLM credential relay protections, was not enabled by default.

“Going forward, CU14 enables this by default on Exchange servers, which is why it is important to upgrade,” Narang said.

Rapid7’s lead software engineer Adam Barnett highlighted CVE-2024-21413, a critical remote code execution bug in Microsoft Office that could be exploited just by viewing a specially-crafted message in the Outlook Preview pane.

“Microsoft Office typically shields users from a variety of attacks by opening files with Mark of the Web in Protected View, which means Office will render the document without fetching potentially malicious external resources,” Barnett said. “CVE-2024-21413 is a critical RCE vulnerability in Office which allows an attacker to cause a file to open in editing mode as though the user had agreed to trust the file.”

Barnett stressed that administrators responsible for Office 2016 installations who apply patches outside of Microsoft Update should note the advisory lists no fewer than five separate patches which must be installed to achieve remediation of CVE-2024-21413; individual update knowledge base (KB) articles further note that partially-patched Office installations will be blocked from starting until the correct combination of patches has been installed.

It’s a good idea for Windows end-users to stay current with security updates from Microsoft, which can quickly pile up otherwise. That doesn’t mean you have to install them on Patch Tuesday. Indeed, waiting a day or three before updating is a sane response, given that sometimes updates go awry and usually within a few days Microsoft has fixed any issues with its patches. It’s also smart to back up your data and/or image your Windows drive before applying new updates.

For a more detailed breakdown of the individual flaws addressed by Microsoft today, check out the SANS Internet Storm Center’s list. For those admins responsible for maintaining larger Windows environments, it often pays to keep an eye on Askwoody.com, which frequently points out when specific Microsoft updates are creating problems for a number of users.

Until earlier this week, the support website for networking equipment vendor Juniper Networks was exposing potentially sensitive information tied to customer products, including which devices customers bought, as well as each product’s warranty status, service contracts and serial numbers. Juniper said it has since fixed the problem, and that the inadvertent data exposure stemmed from a recent upgrade to its support portal.

Sunnyvale, Calif. based Juniper Networks makes high-powered Internet routers and switches, and its products are used in some of the world’s largest organizations. Earlier this week KrebsOnSecurity heard from a reader responsible for managing several Juniper devices, who found he could use Juniper’s customer support portal to find device and support contract information for other Juniper customers.

Logan George is a 17-year-old intern working for an organization that uses Juniper products. George said he found the data exposure earlier this week by accident while searching for support information on a particular Juniper product.

George discovered that after logging in with a regular customer account, Juniper’s support website allowed him to list detailed information about virtually any Juniper device purchased by other customers. Searching on Amazon.com in the Juniper portal, for example, returned tens of thousands of records. Each record included the device’s model and serial number, the approximate location where it is installed, as well as the device’s status and associated support contract information.

Information exposed by the Juniper support portal. Columns not pictured include Serial Number, Software Support Reference number, Product, Warranty Expiration Date and Contract ID.

George said the exposed support contract information is potentially sensitive because it shows which Juniper products are most likely to be lacking critical security updates.

“If you don’t have a support contract you don’t get updates, it’s as simple as that,” George said. “Using serial numbers, I could see which products aren’t under support contracts. And then I could narrow down where each device was sent through their serial number tracking system, and potentially see all of what was sent to the same location. A lot of companies don’t update their switches very often, and knowing what they use allows someone to know what attack vectors are possible.”

In a written statement, Juniper said the data exposure was the result of a recent upgrade to its support portal.

“We were made aware of an inadvertent issue that allowed registered users to our system to access serial numbers that were not associated with their account,” the statement reads. “We acted promptly to resolve this issue and have no reason to believe at this time that any identifiable or personal customer data was exposed in any way. We take these matters seriously and always use these experiences to prevent further similar incidents. We are actively working to determine the root cause of this defect and thank the researcher for bringing this to our attention.”

The company has not yet responded to requests for information about exactly when those overly permissive user rights were introduced. However, the changes may date back to September 2023, when Juniper announced it had rebuilt its customer support portal.

George told KrebsOnSecurity the back-end for Juniper’s support website appears to be supported by Salesforce, and that Juniper likely did not have the proper user permissions established on its Salesforce assets. In April 2023, KrebsOnSecurity published research showing that a shocking number of organizations — including banks, healthcare providers and state and local governments — were leaking private and sensitive data thanks to misconfigured Salesforce installations.

Nicholas Weaver, a researcher at University of California, Berkeley’s International Computer Science Institute (ICSI) and lecturer at UC Davis, said the complexity layered into modern tech support portals leaves much room for error.

“This is a reminder of how hard it is to build these large systems like support portals, where you need to be able to manage gazillions of users with distinct access roles,” Weaver said. “One minor screw up there can produce hilarious results.”

Last month, computer maker Hewlett Packard Enterprise announced it would buy Juniper Networks for $14 billion, reportedly to help beef up the 100-year-old technology company’s artificial intelligence offerings.

Update, 11:01 a.m. ET: An earlier version of this story quoted George as saying he was able to see support information for the U.S. Department of Defense. George has since clarified that while one block of device records he found was labeled “Department of Defense,” that record appears to belong to a different country.

Google continues to struggle with cybercriminals running malicious ads on its search platform to trick people into downloading booby-trapped copies of popular free software applications. The malicious ads, which appear above organic search results and often precede links to legitimate sources of the same software, can make searching for software on Google a dicey affair.

Google says keeping users safe is a top priority, and that the company has a team of thousands working around the clock to create and enforce their abuse policies. And by most accounts, the threat from bad ads leading to backdoored software has subsided significantly compared to a year ago.

But cybercrooks are constantly figuring out ingenious ways to fly beneath Google’s anti-abuse radar, and new examples of bad ads leading to malware are still too common.

For example, a Google search earlier this week for the free graphic design program FreeCAD produced the following result, which shows that a “Sponsored” ad at the top of the search results is advertising the software available from freecad-us[.]org. Although this website claims to be the official FreeCAD website, that honor belongs to the result directly below — the legitimate freecad.org.

How do we know freecad-us[.]org is malicious? A review at DomainTools.com show this domain is the newest (registered Jan. 19, 2024) of more than 200 domains at the Internet address 93.190.143[.]252 that are confusingly similar to popular software titles, including dashlane-project[.]com, filezillasoft[.]com, keepermanager[.]com, and libreofficeproject[.]com.

Some of the domains at this Netherlands host appear to be little more than software review websites that steal content from established information sources in the IT world, including Gartner, PCWorld, Slashdot and TechRadar.

Other domains at 93.190.143[.]252 do serve actual software downloads, but none of them are likely to be malicious if one visits the sites through direct navigation. If one visits openai-project[.]org and downloads a copy of the popular Windows desktop management application Rainmeter, for example, the file that is downloaded has the same exact file signature as the real Rainmeter installer available from rainmeter.net.

But this is only a ruse, says Tom Hegel, principal threat researcher at the security firm Sentinel One. Hegel has been tracking these malicious domains for more than a year, and he said the seemingly benign software download sites will periodically turn evil, swapping out legitimate copies of popular software titles with backdoored versions that will allow cybercriminals to remotely commander the systems.

“They’re using automation to pull in fake content, and they’re rotating in and out of hosting malware,” Hegel said, noting that the malicious downloads may only be offered to visitors who come from specific geographic locations, like the United States. “In the malicious ad campaigns we’ve seen tied to this group, they would wait until the domains gain legitimacy on the search engines, and then flip the page for a day or so and then flip back.”

In February 2023, Hegel co-authored a report on this same network, which Sentinel One has dubbed MalVirt (a play on “malvertising”). They concluded that the surge in malicious ads spoofing various software products was directly responsible for a surge in malware infections from infostealer trojans like IcedID, Redline Stealer, Formbook and AuroraStealer.

Hegel noted that the spike in malicious software-themed ads came not long after Microsoft started blocking by default Office macros in documents downloaded from the Internet. He said the volume of the current malicious ad campaigns from this group appears to be relatively low compared to a year ago.

“It appears to be same campaign continuing,” Hegel said. “Last January, every Google search for ‘Autocad’ led to something bad. Now, it’s like they’re paying Google to get one out of every dozen of searches. My guess it’s still continuing because of the up-and-down [of the] domains hosting malware and then looking legitimate.”

Several of the websites at this Netherlands host (93.190.143[.]252) are currently blocked by Google’s Safebrowsing technology, and labeled with a conspicuous red warning saying the website will try to foist malware on visitors who ignore the warning and continue.

But it remains a mystery why Google has not similarly blocked more than 240+ other domains at this same host, or else removed them from its search index entirely. Especially considering there is nothing else but these domains hosted at that Netherlands IP address, and because they have all remained at that address for the past year.

In response to questions from KrebsOnSecurity, Google said maintaining a safe ads ecosystem and keeping malware off of its platforms is a priority across Google.

“Bad actors often employ sophisticated measures to conceal their identities and evade our policies and enforcement, sometimes showing Google one thing and users something else,” Google said in a written statement. “We’ve reviewed the ads in question, removed those that violated our policies, and suspended the associated accounts. We’ll continue to monitor and apply our protections.”

Google says it removed 5.2 billion ads in 2022, and restricted more than 4.3 billion ads and suspended over 6.7 million advertiser accounts. The company’s latest ad safety report says Google in 2022 blocked or removed 1.36 billion advertisements for violating its abuse policies.

Some of the domains referenced in this story were included in Sentinel One’s February 2023 report, but dozens more have been added since, such as those spoofing the official download sites for Corel Draw, Github Desktop, Roboform and Teamviewer.

This October 2023 report on the FreeCAD user forum came from a user who reported downloading a copy of the software from freecadsoft[.]com after seeing the site promoted at the top of a Google search result for “freecad.” Almost a month later, another FreeCAD user reported getting stung by the same scam.

“This got me,” FreeCAD forum user “Matterform” wrote on Nov. 19, 2023. “Please leave a report with Google so it can flag it. They paid Google for sponsored posts.”

Sentinel One’s report didn’t delve into the “who” behind this ongoing MalVirt campaign, and there are precious few clues that point to attribution. All of the domains in question were registered through webnic.cc, and several of them display a placeholder page saying the site is ready for content. Viewing the HTML source of these placeholder pages shows many of the hidden comments in the code are in Cyrillic.

Trying to track the crooks using Google’s Ad Transparency tools didn’t lead far. The ad transparency record for the malicious ad featuring freecad-us[.]org (in the screenshot above) shows that the advertising account used to pay for the ad has only run one previous ad through Google search: It advertised a wedding photography website in New Zealand.

The apparent owner of that photography website did not respond to requests for comment, but it’s also likely his Google advertising account was hacked and used to run these malicious ads.

The final Patch Tuesday of 2023 is upon us, with Microsoft Corp. today releasing fixes for a relatively small number of security holes in its Windows operating systems and other software. Even more unusual, there are no known “zero-day” threats targeting any of the vulnerabilities in December’s patch batch. Still, four of the updates pushed out today address “critical” vulnerabilities that Microsoft says can be exploited by malware or malcontents to seize complete control over a vulnerable Windows device with little or no help from users.

Among the critical bugs quashed this month is CVE-2023-35628, a weakness present in Windows 10 and later versions, as well as Microsoft Server 2008 and later. Kevin Breen, senior director of threat research at Immersive Labs, said the flaw affects MSHTML, a core component of Windows that is used to render browser-based content. Breen notes that MSHTML also can be found in a number of Microsoft applications, including Office, Outlook, Skype and Teams.

“In the worst-case scenario, Microsoft suggests that simply receiving an email would be enough to trigger the vulnerability and give an attacker code execution on the target machine without any user interaction like opening or interacting with the contents,” Breen said.

Another critical flaw that probably deserves priority patching is CVE-2023-35641, a remote code execution weakness in a built-in Windows feature called the Internet Connection Sharing (ICS) service that lets multiple devices share an Internet connection. While CVE-2023-35641 earned a high vulnerability severity score (a CVSS rating of 8.8), the threat from this flaw may be limited somewhat because an attacker would need to be on the same network as the target. Also, while ICS is present in all versions of Windows since Windows 7, it is not on by default (although some applications may turn it on).

Satnam Narang, senior staff research engineer at Tenable, notes that a number of the non-critical patches released today were identified by Microsoft as “more likely to be exploited.” For example, CVE-2023-35636, which Microsoft says is an information disclosure vulnerability in Outlook. An attacker could exploit this flaw by convincing a potential victim to open a specially crafted file delivered via email or hosted on a malicious website.

Narang said what makes this one stand out is that exploitation of this flaw would lead to the disclosure of NTLM hashes, which could be leveraged as part of an NTLM relay or “pass the hash” attack, which lets an attacker masquerade as a legitimate user without ever having to log in.

”It is reminiscent of CVE-2023-23397, an elevation of privilege vulnerability in Microsoft Outlook that was exploited in the wild as a zero day and patched in the March 2023 Patch Tuesday release,” Narang said. “However, unlike CVE-2023-23397, CVE-2023-35636 is not exploitable via Microsoft’s Preview Pane, which lowers the severity of this flaw.”

As usual, the SANS Internet Storm Center has a good roundup on all of the patches released today and indexed by severity. Windows users, please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.

When KrebsOnSecurity broke the news on Oct. 20, 2023 that identity and authentication giant Okta had suffered a breach in its customer support department, Okta said the intrusion allowed hackers to steal sensitive data from fewer than one percent of its 18,000+ customers. But today, Okta revised that impact statement, saying the attackers also stole the name and email address for nearly all of its customer support users.

Okta acknowledged last month that for several weeks beginning in late September 2023, intruders had access to its customer support case management system. That access allowed the hackers to steal authentication tokens from some Okta customers, which the attackers could then use to make changes to customer accounts, such as adding or modifying authorized users.

In its initial incident reports about the breach, Okta said the hackers gained unauthorized access to files inside Okta’s customer support system associated with 134 Okta customers, or less than 1% of Okta’s customer base.

But in an updated statement published early this morning, Okta said it determined the intruders also stole the names and email addresses of all Okta customer support system users.

“All Okta Workforce Identity Cloud (WIC) and Customer Identity Solution (CIS) customers are impacted except customers in our FedRamp High and DoD IL4 environments (these environments use a separate support system NOT accessed by the threat actor),” Okta’s advisory states. “The Auth0/CIC support case management system was also not impacted by this incident.”

Okta said that for nearly 97 percent of users, the only contact information exposed was full name and email address. That means about three percent of Okta customer support accounts had one or more of the following data fields exposed (in addition to email address and name): last login; username; phone number; SAML federation ID; company name; job role; user type; date of last password change or reset.

Okta notes that a large number of the exposed accounts belong to Okta administrators — IT people responsible for integrating Okta’s authentication technology inside customer environments — and that these individuals should be on guard for targeted phishing attacks.

“Many users of the customer support system are Okta administrators,” Okta pointed out. “It is critical that these users have multi-factor authentication (MFA) enrolled to protect not only the customer support system, but also to secure access to their Okta admin console(s).”

While it may seem completely bonkers that some companies allow their IT staff to operate company-wide authentication systems using an Okta administrator account that isn’t protected with MFA, Okta said fully six percent of its customers (more than 1,000) persist in this dangerous practice.

In a previous disclosure on Nov. 3, Okta blamed the intrusion on an employee who saved the credentials for a service account in Okta’s customer support infrastructure to their personal Google account, and said it was likely those credentials were stolen when the employee’s personal device using the same Google account was compromised.

Unlike standard user accounts, which are accessed by humans, service accounts are mostly reserved for automating machine-to-machine functions, such as performing data backups or antivirus scans every night at a particular time. For this reason, they can’t be locked down with multifactor authentication the way user accounts can.

Dan Goodin over at Ars Technica reckons this explains why MFA wasn’t set up on the compromised Okta service account. But as he rightly points out, if a transgression by a single employee breaches your network, you’re doing it wrong.

“Okta should have put access controls in place besides a simple password to limit who or what could log in to the service account,” Goodin wrote on Nov. 4. “One way of doing this is to put a limit or conditions on the IP addresses that can connect. Another is to regularly rotate access tokens used to authenticate to service accounts. And, of course, it should have been impossible for employees to be logged in to personal accounts on a work machine. These and other precautions are the responsibility of senior people inside Okta.”

Goodin suggested that people who want to delve further into various approaches for securing service accounts should read this thread on Mastodon.

“A fair number of the contributions come from security professionals with extensive experience working in sensitive cloud environments,” Goodin wrote.

In the summer of 2022, KrebsOnSecurity documented the plight of several readers who had their accounts at big-three consumer credit reporting bureau Experian hijacked after identity thieves simply re-registered the accounts using a different email address. Sixteen months later, Experian clearly has not addressed this gaping lack of security. I know that because my account at Experian was recently hacked, and the only way I could recover access was by recreating the account.

Entering my SSN and birthday at Experian showed my identity was tied to an email address I did not authorize.

I recently ordered a copy of my credit file from Experian via annualcreditreport.com, but as usual Experian declined to provide it, saying they couldn’t verify my identity. Attempts to log in to my account directly at Experian.com also failed; the site said it didn’t recognize my username and/or password.

A request for my Experian account username required my full Social Security number and date of birth, after which the website displayed portions of an email address I never authorized and did not recognize (the full address was redacted by Experian).

I immediately suspected that Experian was still allowing anyone to recreate their credit file account using the same personal information but a different email address, a major authentication failure that was explored in last year’s story, Experian, You Have Some Explaining to Do. So once again I sought to re-register as myself at Experian.

The homepage said I needed to provide a Social Security number and mobile phone number, and that I’d soon receive a link that I should click to verify myself. The site claims that the phone number you provide will be used to help validate your identity. But it appears you could supply any phone number in the United States at this stage in the process, and Experian’s website would not balk. Regardless, users can simply skip this step by selecting the option to “Continue another way.”

Experian then asks for your full name, address, date of birth, Social Security number, email address and chosen password. After that, they require you to successfully answer between three to five multiple-choice security questions whose answers are very often based on public records. When I recreated my account this week, only two of the five questions pertained to my real information, and both of those questions concerned street addresses we’ve previously lived at — information that is just a Google search away.

Assuming you sail through the multiple-choice questions, you’re prompted to create a 4-digit PIN and provide an answer to one of several pre-selected challenge questions. After that, your new account is created and you’re directed to the Experian dashboard, which allows you to view your full credit file, and freeze or unfreeze it.

At this point, Experian will send a message to the old email address tied to the account, saying certain aspects of the user profile have changed. But this message isn’t a request seeking verification: It’s just a notification from Experian that the account’s user data has changed, and the original user is offered zero recourse here other than to a click a link to log in at Experian.com.

If you don’t have an Experian account, it’s a good idea to create one. Because at least then you will receive one of these  emails when someone hijacks your credit file at Experian.

And of course, a user who receives one of these notices will find that the credentials to their Experian account no longer work. Nor do their PIN or account recovery question, because those have been changed also. Your only option at this point is recreate your account at Experian and steal it back from the ID thieves!

In contrast, if you try to modify an existing account at either of the other two major consumer credit reporting bureaus — Equifax or TransUnion — they will ask you to enter a code sent to the email address or phone number on file before any changes can be made.

Reached for comment, Experian declined to share the full email address that was added without authorization to my credit file.

“To ensure the protection of consumers’ identities and information, we have implemented a multi-layered security approach, which includes passive and active measures, and are constantly evolving,” Experian spokesperson Scott Anderson said in an emailed statement. “This includes knowledge-based questions and answers, and device possession and ownership verification processes.”

Anderson said all consumers have the option to activate a multi-factor authentication method that’s requested each time they log in to their account. But what good is multi-factor authentication if someone can simply recreate your account with a new phone number and email address?

Several readers who spotted my rant about Experian on Mastodon earlier this week responded to a request to validate my findings. The Mastodon user @Jackerbee is a reader from Michican who works in the biotechnology industry. @Jackerbee said when prompted by Experian to provide his phone number and the last four digits of his SSN, he chose the option to “manually enter my information.”

“I put my second phone number and the new email address,” he explained. “I received a single email in my original account inbox that said they’ve updated my information after I ‘signed up.’ No verification required from the original email address at any point. I also did not receive any text alerts at the original phone number. The especially interesting and egregious part is that when I sign in, it does 2FA with the new phone number.”

The Mastodon user PeteMayo said they recreated their Experian account twice this week, the second time by supplying a random landline number.

“The only difference: it asked me FIVE questions about my personal history (last time it only asked three) before proclaiming, ‘Welcome back, Pete!,’ and granting full access,” @PeteMayo wrote. “I feel silly saving my password for Experian; may as well just make a new account every time.”

I was fortunate in that whoever hijacked my account did not also thaw my credit freeze.  Or if they did, they politely froze it again when they were done. But I fully expect my Experian account will be hijacked yet again unless Experian makes some important changes to its authentication process.

It boggles the mind that these fundamental authentication weaknesses have been allowed to persist for so long at Experian, which already has a horrible track record in this regard.

In December 2022, KrebsOnSecurity alerted Experian that identity thieves had worked out a remarkably simple way to bypass its security and access any consumer’s full credit report — armed with nothing more than a person’s name, address, date of birth, and Social Security number. Experian fixed the glitch, and acknowledged that it persisted for nearly seven weeks, between Nov. 9, 2022 and Dec. 26, 2022.

In April 2021, KrebsOnSecurity revealed how identity thieves were exploiting lax authentication on Experian’s PIN retrieval page to unfreeze consumer credit files. In those cases, Experian failed to send any notice via email when a freeze PIN was retrieved, nor did it require the PIN to be sent to an email address already associated with the consumer’s account.

A few days after that April 2021 story, KrebsOnSecurity broke the news that an Experian API was exposing the credit scores of most Americans.

More greatest hits from Experian:

2022: Class Action Targets Experian Over Account Security
2017: Experian Site Can Give Anyone Your Credit Freeze PIN
2015: Experian Breach Affects 15 Million Customers
2015: Experian Breach Tied to NY-NJ ID Theft Ring
2015: At Experian, Security Attrition Amid Acquisitions
2015: Experian Hit With Class Action Over ID Theft Service
2014: Experian Lapse Allowed ID Theft Service Access to 200 Million Consumer Records
2013: Experian Sold Consumer Data to ID Theft Service