A sophisticated Lazarus subgroup has been actively targeting financial and cryptocurrency organizations over the past two years, using a suite of remote access trojans (RATs) to infiltrate and control compromised systems. This group, which has been identified as a significant threat actor, overlaps with well-known campaigns like AppleJeus, Citrine Sleet, UNC4736, and Gleaming Pisces. The core of their operation relies on a trio of malicious tools: PondRAT, ThemeForestRAT, and RemotePE, each playing a specific role in their multi-stage intrusion process. Their tactics, techniques, and procedures (TTPs) are highly advanced, as demonstrated in a 2024 incident response case where a decentralized finance firm was compromised through a meticulously planned attack.
The 2024 incident began with a social engineering attack on a firm employee. The attacker, impersonating a colleague, lured the victim into a Telegram conversation and directed them to a spoofed meeting site. Shortly after the victim accessed the site, PondRAT was deployed on their Windows machine. Forensic analysis revealed a suspicious drop in endpoint logging, which suggested a suspected Chrome zero-day exploit was used to execute the code without detection. Over the next three months, the attackers used PondRAT in conjunction with custom-built tools, including a screenshotter, keylogger, and browser dumper, to harvest credentials and map the network. They also used public utilities like Mimikatz and the Fast Reverse Proxy client to further their reconnaissance.
Once the initial reconnaissance phase was complete, the attackers removed the PondRAT and ThemeForestRAT artifacts and installed RemotePE, a more advanced RAT, on the victim’s system. This likely served to maintain deeper, more persistent access to the high-value target. PondRAT, often referred to as a “firstloader,” has been in use since at least 2021 and is known for its ties to the AppleJeus campaign. It shares many similarities with the older POOLRAT/SimpleTea family, including identical XOR keys, function names, and a unique bot-ID generation scheme. However, it is a lighter-weight variant, lacking features like timestomping and C2 configuration files, which aligns with its primary role as an initial loader.
ThemeForestRAT has remained largely unanalyzed by the public despite its use for over six years. It’s often loaded into memory via PondRAT and offers a wide array of commands, including secure file deletion, timestomping, and in-process shellcode injection. It operates by spawning two threads on Windows systems: one that creates a temporary folder and another that monitors console and RDP sessions to execute configured commands. The configuration for ThemeForestRAT is stored in a 43 KB RC4-encrypted file called netraid.inf, which defines C2 URLs and other operational parameters. Its C2 protocol utilizes HTTP(S) file transfers prefixed with “ThemeForest_” and “Thumb_.”
The design of ThemeForestRAT shares core features with the RomeoGolf RAT from 2013, suggesting a clear line of code inheritance within the Lazarus group. These shared features include the use of two signaling threads, config-file timestomping, and unique-ID routines. Interestingly, the functionality to detect and copy data from newly attached logical drives, a feature present in its predecessors, has been removed in ThemeForestRAT, while the temporary directory creation remains intact. This evolution in the RAT’s design highlights the attackers’ continuous efforts to refine their tools and adapt to changing security landscapes.
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