Cybersecurity researchers have flagged the tactical similarities between the risk actors behind the RomCom RAT and a cluster that has been noticed delivering a loader dubbed TransferLoader.
Enterprise security agency Proofpoint is monitoring the exercise related to TransferLoader to a gaggle dubbed UNK_GreenSec and the RomCom RAT actors below the moniker TA829. The latter can be identified by the names CIGAR, Nebulous Mantis, Storm-0978, Tropical Scorpius, UAC-0180, UAT-5647, UNC2596, and Void Rabisu.
The corporate mentioned it found UNK_GreenSec as a part of its investigation into TA829, describing it as utilizing an “uncommon quantity of comparable infrastructure, supply techniques, touchdown pages, and electronic mail lure themes.”
TA829 is one thing of an uncommon hacking group within the risk panorama given its capacity to conduct each espionage in addition to financially motivated assaults. The Russia-aligned hybrid group has additionally been linked to the zero-day exploitation of security flaws in Mozilla Firefox and Microsoft Home windows to ship RomCom RAT in assaults aimed toward world targets.
Earlier this yr, PRODAFT detailed the risk actors’ use of bulletproof internet hosting suppliers, living-off-the-land (LOTL) techniques, and encrypted command-and-control (C2) communications to sidestep detection.
TransferLoader, then again, was first documented by Zscaler ThreatLabz in reference to a February 2025 marketing campaign that delivered the Morpheus ransomware in opposition to an unnamed American legislation agency.
Proofpoint famous that campaigns undertaken by each TA829 and UNK_GreenSec depend on REM Proxy companies which are deployed on compromised MikroTik routers for his or her upstream infrastructure. That mentioned, the precise methodology used to breach these units just isn’t identified.
“REM Proxy units are possible rented to customers to relay site visitors,” the Proofpoint risk analysis staff mentioned. “In noticed campaigns, each TA829 and UNK_GreenSec use the service to relay site visitors to new accounts at freemail suppliers to then ship to targets. REM Proxy companies have additionally been utilized by TA829 to provoke related campaigns through compromised electronic mail accounts.”
Provided that the format of the sender addresses are related — e.g., ximajazehox333@gmail.com and hannahsilva1978@ukr.web — it is believed that the risk actors are possible utilizing some type of an electronic mail builder utility that facilitates the en masse creation and sending of phishing emails through REM Proxy nodes.
The messages act as a conduit to ship a hyperlink, which is both straight embedded within the physique or inside a PDF attachment. Clicking on the hyperlink initiates a collection of redirections through Rebrandly that in the end take the sufferer to a pretend Google Drive or Microsoft OneDrive web page, whereas filtering out machines which have been flagged as sandboxes or deemed not of curiosity to the attackers.
It is at this stage that the assault chains splinter into two, because the adversary infrastructure to which the targets are redirected is completely different, in the end paving the way in which for TransferLoader within the case of UNK_GreenSec and a malware pressure referred to as SlipScreen within the case of TA829.
“TA829 and UNK_GreenSec have each deployed Putty’s PLINK utility to arrange SSH tunnels, and each used IPFS companies to host these utilities in follow-on exercise,” Proofpoint famous.
SlipScreen is a first-stage loader that is designed to decrypt and cargo shellcode straight into reminiscence and provoke communications with a distant server, however solely after a Home windows Registry test to make sure the focused pc has not less than 55 latest paperwork primarily based on the “HKCUSOFTWAREMicrosoftWindowsCurrentVersionExplorerRecentDocs” key.
The an infection sequence is then used to deploy a downloader named MeltingClaw (aka DAMASCENED PEACOCK) or RustyClaw, which is then used to drop backdoors like ShadyHammock or DustyHammock, with the previous getting used to launch SingleCamper (aka SnipBot), an up to date model of RomCom RAT.
DustyHammock, in addition to working reconnaissance instructions on an contaminated system, comes fitted with the flexibility to obtain extra payloads hosted on the InterPlanetary File System (IPFS) community.
Campaigns propagating TransferLoader have been discovered to leverage job opportunity-themed messages to trick victims into clicking on a hyperlink that ostensibly results in a PDF resume, however, in actuality, ends in the obtain of TransferLoader from an IPFS webshare.
TransferLoader’s main goal is to fly below the radar and serve extra malware, comparable to Metasploit and Morpheus ransomware, a rebranded model of HellCat ransomware.
“Not like the TA829 campaigns, the TransferLoader campaigns’ JavaScript elements redirected customers to a distinct PHP endpoint on the identical server, which permits the operator to conduct additional server-side filtering,” Proofpoint mentioned. “UNK_GreenSec used a dynamic touchdown web page, typically irrelevant to the OneDrive spoof, and redirected customers to the ultimate payload that was saved on an IPFS webshare.”
The overlapping tradecraft between TA829 and UNK_GreenSec raises one of many 4 prospects –
- The risk actors are procuring distribution and infrastructure from the identical third-party supplier
- TA829 acquires and distributes infrastructure by itself, and has offered these companies to UNK_GreenSec
- UNK_GreenSec is the infrastructure supplier that sometimes gives its warez to TA829, however determined to quickly use it to ship its personal malware, TransferLoader
- TA829 and UNK_GreenSec are one and the identical, and TransferLoader is a brand new addition to their malware arsenal
“Within the present risk panorama, the factors at which cybercrime and espionage exercise overlap proceed to extend, eradicating the distinctive boundaries that separate legal and state actors,” Proofpoint mentioned. “Campaigns, indicators, and risk actor behaviors have converged, making attribution and clustering throughout the ecosystem more difficult.”
“Whereas there’s not enough proof to substantiate the precise nature of the connection between TA829 and UNK_GreenSec, there’s very possible a hyperlink between the teams.”
