Chinese APTs Expand Targets, Update Backdoors in Recent Campaigns

Summary

Two China-linked APT groups have intensified operations with expanded targeting and updated malware tools. Salt Typhoon targeted an Azerbaijani energy company using ProxyNotShell exploits and updated Deed RAT via DLL sideloading, while Twill Typhoon has targeted Asia-Pacific entities with a new modular .NET-based RAT framework called FDMTP. Both campaigns demonstrate sustained, adaptive intrusion activity with repeated access attempts and payload updates.

Full text

China-linked state-sponsored hackers have been observed expanding their targets and updating malicious tools in fresh campaigns that either follow known patterns or adapt to current political events. Between December 2025 and February 2026, Salt Typhoon, also known as Earth Estries, FamousSparrow, GhostEmperor, and UNC2286, and considered one of the most aggressive Chinese APTs, was seen targeting an Azerbaijani oil and gas company, Bitdefender reports. The campaign marked a shift from typical Salt Typhoon activity and was apparently aimed at government, telecoms, and technology entities in the US, Asia, the Middle East, and Africa, likely triggered by Azerbaijan’s recently increased role in European energy security. According to Bitdefender, as a result of Russia’s Ukraine gas transit agreement expiration and the recent Strait of Hormuz disruptions, Azerbaijan has become a strategic energy partner for European countries, putting it in APT crosshairs. The recently observed intrusion, attributed with moderate-to-high confidence to Salt Typhoon, started with Microsoft Exchange vulnerability exploitation, followed by web shell deployment, command execution, DLL sideloading, and backdoor deployment. In December, the threat actor used the ProxyNotShell exploit chain for code execution on Exchange servers, deployed web shells to establish a foothold, and then deployed the Deed RAT via an updated DLL sideloading technique.Advertisement. Scroll to continue reading. The backdoor was hidden in a folder mimicking the legitimate LogMeIn Hamachi installation, and persistence was achieved through a service masquerading as LogMeIn Hamachi, which was launched at system startup. After compromising the initial host, the attackers abused RDP to access a second server, logged in to an administrator account, and then deployed Deed RAT, likely as part of hands-on keyboard activity. Next, they used Impacket tools to compromise a third host. A month later, after the malware was removed from at least one host, the hackers accessed the initially compromised server and deployed the TernDoor backdoor, which was linked to Salt Typhoon by Cisco’s Talos security researchers. At the end of February, the APT accessed the victim organization’s environment again, attempting to redeploy Deed RAT using the same execution chain. “This intrusion should not be viewed as an isolated compromise, but as a sustained and adaptive operation conducted by an actor that repeatedly sought to regain and extend access within the victim environment. Across multiple waves of activity, the same access path was revisited, new payloads were introduced, and additional footholds were established,” Bitdefender notes. Twill Typhoon attacks Beginning September 2025 and continuing through at least April 2026, Darktrace observed the China-linked APT Twill Typhoon (also known as Bronze President, Camaro Dragon, Earth Preta, Mustang Panda, and TA416) targeting entities in the Asia-Pacific and Japan (APJ) region with an updated arsenal, including a modular .NET-based RAT framework. Multiple infected hosts, the security firm reports, were seen making requests to domains impersonating content delivery networks (CDNs), including Yahoo and Apple services, and retrieving legitimate binaries alongside matching .config files and malicious DLLs. The fetched sequence, a hallmark of China-nexus campaigns, leads to the execution of a new RAT framework dubbed FDMTP, via DLL sideloading. During attacks observed in September and October, the compromised hosts retrieved a DLL from the same external hosts repeatedly. In April, a system within a financial organization’s network fetched a legitimate binary and then repeatedly retrieved config files and DLL components. The attackers relied on Visual Studio hosting and the legitimate Windows ClickOnce engine to ensure the malware’s execution. The main payload was a modular framework relying on various plugins for backdoor functionality. The RAT supports system fingerprinting, command execution, manipulating Windows tasks, managing registry persistence, manipulating system processes, and retrieving files and commands. “Intrusions are not dependent on a single foothold, but distributed across components that can be updated, replaced, or reloaded independently. This approach is consistent with broader China-nexus tradecraft,” Darktrace notes. 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Indicators of Compromise

• malware — Deed RAT
• malware — TernDoor
• malware — FDMTP

Entities