Chinese Threat Actors Employ Operational Relay Box (ORB) Networks to Evade IOCs
23 May 2024 at 09:15
Cybersecurity defenders have widely relied on blocking attacker IP addresses through identified IOCs in response to threat actor campaigns. However, Chinese threat actors are rapidly rendering this usual strategy obsolete through the widespread adoption of ORB Networks.
ORBs are complex, multi-layered networks, typically managed by private companies or entities within the Chinese government. They offer access to a constantly shifting pool of IP addresses, allowing multiple threat actors to mask their activities behind seemingly innocuous traffic.
Use of ORB Networks by Threat Actors Present Additional Challenges to Defenders
Researchers from Mandiant stated that the sheer size and scope of these networks, often hundreds of thousands of nodes deep, provide a great deal of cover and make it difficult for defenders to attribute and learn more about attackers. Additionally, the geographic spread of ORBs allows hackers in China to circumvent geographic restrictions or appear less suspicious by connecting to targets from within their own region. Most importantly, ORB nodes are short-lived, with new devices typically cycled in and out every month or few months, making it difficult for defenders to tie IPs to their users for any good amounts of time. These operational relay box networks (ORBs) are maintained by private companies or elements within the Chinese government and are made up of five layers: Chinese servers, virtual private servers (VPS), traversal nodes, exit nodes, and victim servers. ORBs can be classified into two groups: provisioned, which use commercially rented VPS's, and nonprovisioned, built on compromised and end-of-life routers and Internet of Things (IoT) devices. These networks are akin to botnets and ORB network administrators can easily grow the size of their network with little effort and create a constantly evolving mesh network that can be used to conceal espionage operations. The researchers cited two prominent examples to illustrate the sophistication of these networks:- ORB3/SPACEHOP: A provisioned network linked to APT5 and APT15, targeting entities in North America, Europe, and the Middle East. Known for exploiting vulnerabilities like CVE-2022-27518.
- ORB2/FLORAHOX: A hybrid network employing compromised Cisco, ASUS, and DrayTek routers, alongside TOR network relays and VPS servers. Linked to APT31 and Zirconium, demonstrating a multi-layered approach to traffic obfuscation.