Cybersecurity researchers have flagged the tactical similarities between the menace actors behind the RomCom RAT and a cluster that has been noticed delivering a loader dubbed TransferLoader.
Enterprise safety agency Proofpoint is monitoring the exercise related to TransferLoader to a gaggle dubbed UNK_GreenSec and the RomCom RAT actors underneath the moniker TA829. The latter can also be identified by the names CIGAR, Nebulous Mantis, Storm-0978, Tropical Scorpius, UAC-0180, UAT-5647, UNC2596, and Void Rabisu.
The corporate stated it found UNK_GreenSec as a part of its investigation into TA829, describing it as utilizing an “uncommon quantity of comparable infrastructure, supply ways, touchdown pages, and e mail lure themes.”
TA829 is one thing of an uncommon hacking group within the menace panorama given its means 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 safety flaws in Mozilla Firefox and Microsoft Home windows to ship RomCom RAT in assaults aimed toward international targets.
Earlier this 12 months, PRODAFT detailed the menace actors’ use of bulletproof internet hosting suppliers, living-off-the-land (LOTL) ways, and encrypted command-and-control (C2) communications to sidestep detection.
TransferLoader, however, was first documented by Zscaler ThreatLabz in reference to a February 2025 marketing campaign that delivered the Morpheus ransomware towards an unnamed American regulation agency.
Proofpoint famous that campaigns undertaken by each TA829 and UNK_GreenSec depend on REM Proxy providers which can be deployed on compromised MikroTik routers for his or her upstream infrastructure. That stated, the precise technique used to breach these gadgets is just not identified.
“REM Proxy gadgets are doubtless rented to customers to relay visitors,” the Proofpoint menace analysis crew stated. “In noticed campaigns, each TA829 and UNK_GreenSec use the service to relay visitors to new accounts at freemail suppliers to then ship to targets. REM Proxy providers have additionally been utilized by TA829 to provoke comparable campaigns by way of compromised e mail accounts.”
Provided that the format of the sender addresses are comparable — e.g., [email protected] and [email protected] — it is believed that the menace actors are doubtless utilizing some kind of an e mail builder utility that facilitates the en masse creation and sending of phishing emails by way of REM Proxy nodes.
The messages act as a conduit to ship a hyperlink, which is both instantly embedded within the physique or inside a PDF attachment. Clicking on the hyperlink initiates a sequence of redirections by way of Rebrandly that finally take the sufferer to a faux Google Drive or Microsoft OneDrive web page, whereas filtering out machines which were 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 totally different, finally paving the way in which for TransferLoader within the case of UNK_GreenSec and a malware pressure known 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 providers to host these utilities in follow-on exercise,” Proofpoint famous.
SlipScreen is a first-stage loader that is designed to decrypt and cargo shellcode instantly into reminiscence and provoke communications with a distant server, however solely after a Home windows Registry verify to make sure the focused laptop has at the very least 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 operating reconnaissance instructions on an contaminated system, comes fitted with the power 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 major goal is to fly underneath the radar and serve extra malware, resembling Metasploit and Morpheus ransomware, a rebranded model of HellCat ransomware.
“In contrast to the TA829 campaigns, the TransferLoader campaigns’ JavaScript elements redirected customers to a special PHP endpoint on the identical server, which permits the operator to conduct additional server-side filtering,” Proofpoint stated. “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 potentialities –
- The menace actors are procuring distribution and infrastructure from the identical third-party supplier
- TA829 acquires and distributes infrastructure by itself, and has supplied these providers to UNK_GreenSec
- UNK_GreenSec is the infrastructure supplier that sometimes provides its warez to TA829, however determined to briefly 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 menace panorama, the factors at which cybercrime and espionage exercise overlap proceed to extend, eradicating the distinctive limitations that separate prison and state actors,” Proofpoint stated. “Campaigns, indicators, and menace actor behaviors have converged, making attribution and clustering inside the ecosystem more difficult.”
“Whereas there may be not enough proof to substantiate the precise nature of the connection between TA829 and UNK_GreenSec, there may be very doubtless a hyperlink between the teams.”
