Cloud Security
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Critical Infrastructure Security
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Cyberwarfare / Nation-State Attacks
Beijing’s Tough-to-Track Mesh Networks Built Using Hacked Devices, Mandiant Warns
Multiple Chinese cyber espionage groups have embraced a new tactic to avoid detection and complicate efforts to track their activities.
Beijing cyberespionage groups such as Volt Typhoon, aka Bronze Silhouette, have been adopting operational relay box networks, aka ORBs, oftentimes running them off of stolen or leased proxies, or via home or small office routers (see: US CISA Urges Preventative Actions Against Volt Typhoon).
The use of ORBs has long been tied to Western intelligence agencies, who have employed them to screen offensive activities from targets and adversaries, and hide the source of an attack. Commercial versions of ORB networks appeared in 2016, with Chinese espionage groups appearing to embrace them around 2020, say researchers from Google Cloud’s Mandiant.
Multiple groups of nation-state attackers can use a single ORB network like a botnet to handle command-and-control communications between attackers’ infrastructure and a victim’s environment, says a new report from the threat intel firm. The attack infrastructure often is a combination of leased virtual private servers, as well as compromised or end-of-life SOHO and other edge devices, Internet of Things equipment or any “smart” device that connects to the internet, all of which gets frequently cycled.
“Building networks of compromised devices allows ORB network administrators to easily grow the size of their ORB with little effort and create a constantly evolving mesh network that can be used to conceal espionage operations,” the report says. One ORB network that Mandiant tracks as ORB3, aka Spacehop, maintains nodes in multiple geographies – especially in Europe, the Middle East and the United States – which demonstrates how even a single network can have a global reach.
“ORB networks are one of the major innovations in Chinese cyber espionage that are challenging defenders,” said Michael Raggi, principal analyst at Mandiant. “They’re like a maze that is continually reconfiguring with the entrance and the exit disappearing from the maze every 60 to 90 days.”
Increasing adoption of ORB networks to screen attacks and complicate attribution requires that defenders track ORBs as they might do with APT groups.
In part, that’s because an egress IP addresses is not a reliable indicator of who might be behind the attack, since it might be an otherwise legitimate device being used as a temporary proxy via an ORB network, Mandiant said.
“These networks allow actors to egress from devices that have a geographic proximity to targeted enterprises, which allows traffic to blend in or otherwise not be anomalous when being reviewed by analysts or operational personnel making risk-based access decisions, it said. “One such example would be traffic from a residential ISP that is in the same geographic location as the target that is regularly used by employees and would be less likely to get picked up for manual review.”
The device owner or operator might be unaware that nation-state attackers are using their equipment to proxy into a target’s IT environment. Chinese espionage groups have also been using ORB networks to target critical infrastructure, including operational technology environments (see: Here’s How the FBI Stopped a Major Chinese Hacking Campaign).
“To target someone, these actors may be coming from a home router right down the street. It’s not unusual for an entirely unwitting person’s home router to be involved in an act of espionage,” Raggi said.
Mandiant said attacker-controlled ORB networks are typically comprised of these essential components:
- Adversary-controlled operations server: Used to administer nodes within an ORB network. ACOS typically get hosted in a Chinese or Hong Kong IP space.
- Relay node: Oftentimes a VPS leased from “a major China or Hong Kong-based cloud provider,” which enables ORB users “to authenticate to the network and relay traffic through the larger traversal pool on ORB nodes.”
- Traversal nodes: These comprise the majority of nodes in an ORB network and “are used to relay traffic across an ORB network obfuscating the origin of network traffic.” Each node can be provisioned, via virtual private servers, or non-provisioned, typically via compromised devices.
- Exit/staging nodes: Actor-controlled nodes used for “egress from an ORB network into a victim environment.”
- Victim server: Infrastructure inside a victim’s environment that communicates with an attacker’s ORB network node.
Whoever is administering ORB networks on behalf of Beijing appears to provide access to any given one to multiple APT groups, as well as to regularly cycle the infrastructure that comprises the ORB – sometimes in as little as 31 days – which further complicates efforts to track these networks. “A competitive differentiator among ORB network contractors in China appears to be their ability to cycle significant percentages of their compromised or leased infrastructure on a monthly basis,” Mandiant said.
All of this adds up to more stealthy operations. “Chinese cyber espionage was once noisy and easily trackable. This is a new type of adversary,” said John Hultquist, chief analyst at Mandiant.
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