Researchers have discovered links between several cyber espionage groups believed to be sponsored by the Chinese government and found that at least some of them may be working from the Xicheng District of Beijing.

A report published last week by 401TRG, the threat research and analysis team at ProtectWise, revealed links between several campaigns conducted over the past decade. Researchers claim that various threat groups previously attributed to Chinese-speaking actors are all connected to China’s state intelligence apparatus under what they call the “Winnti umbrella.”

Threat actors such as Winnti, Gref, PlayfullDragon, APT17, DeputyDog, Axiom, BARIUM, LEAD, PassCV, Wicked Panda, and ShadowPad are all believed to be part of the Winnti umbrella based on the use of similar tactics, techniques, and procedures (TTPs), and overlaps in infrastructure and operations. Experts believe they are “the work of individual teams, including contractors external to the Chinese government, with varying levels of expertise, cooperating on a specific agenda.”

These hacker groups have been active since at least 2009 – possibly as early as 2007 – and their initial targets are often gaming studios and high-tech companies located in countries such as the United States, Japan, South Korea and China. The main goal appears to be harvesting code-signing certificates and manipulating software, with a secondary objective of financial gain.

Researchers said the Winnti umbrella’s main targets appear to be political, such as Uyghur and Tibetan activists, Tibetan and Chinese journalists, the government of Thailand (e.g. Bookworm), and major international tech companies.

These groups continue to launch campaigns, with operations seen as recently as late March. In the attacks observed this year, the hackers have focused on phishing – particularly targeted at Office 365 and Gmail accounts – rather than malware and exploits.

The cyberspies often target cloud storage accounts from which they hope to obtain code-signing certificates. In some cases, they also seek files and documents that could help them escalate privileges and move laterally within the victim’s network.

While the attackers have taken steps to hide their identity, they have made some mistakes, providing investigators important clues about their possible location.

“In the attackers’ ideal situation, all remote access occurs through their own C2 infrastructure, which acts as a proxy and obscures their true location,” 401TRG said in its report. “However, we have observed a few cases of the attackers mistakenly accessing victim machines without a proxy, potentially identifying the true location of the individual running the session. In all of these cases, the net block was 221.216.0.0/13, the China Unicom Beijing Network, Xicheng District.”

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