A financially motivated threat actor believed to speak Russian has used remote access Trojans (RATs) in attacks on financial entities in the United States and worldwide, Israel-based security firm CyberInt reports.
Tracked by the research community as TA505, the Russian threat group is known for the use of banking Trojans such as Shifu and Dridex, as well as for the massive Locky ransomware campaigns observed several years ago.
Over the past months, the actor was observed switching to new backdoors in their attacks, including tRat, which is modular in nature, and ServHelper. Both RATs are written in Delphi.
In attack campaigns launched between December 2018 and February 2019, TA505 was observed employing the Remote Manipulator System (RMS) backdoor to target financial institutions in Chile, India, Italy, Malawi, Pakistan and South Korea, as well as retailers in the United States, CyberInt says in a new report (PDF).
In mid-December 2018, the threat actor was observed targeting large US retailers and organizations in the food and beverage industry.
The attacks started with spear-phishing emails that attempted to trick the users into opening a malicious Word document containing a Visual Basic for Applications (VBA) macro to download a payload from the command and control (C&C) server. At the final stage, the RMS RAT was installed on the victim’s machine.
Analysis of these attacks led to the discovery of a more wide-spread campaign that started in December 2018 and continued to be active until March 2019, hitting targets in Chile, India, Italy, Malawi, Pakistan and South Korea, and also believed to have affected China, Great Britain, France and the United States.
The malicious documents used in these attacks spawn a Microsoft Windows Installer process to fetch an additional payload from the command and control (C&C) sever. CyberInt’s security researchers identified four C&C servers and payloads used in this campaign.
“This behavior is consistent with other TA505 campaigns utilizing a combination of weaponized Microsoft Office files containing either VBA macros or exploit code to spawn additional processes,” the researchers say.
The ServHelper RAT that was first identified in November last year was observed being dropped onto the victims’ machines in these attacks. The malware can set up reverse SSH tunnels to allow attackers to access the infected host via Remote Desktop Protocol (RDP).
The same tactics, techniques and procedures (TTPs) were observed in an attack on the Notary Chamber of Ukraine, where the threat actor attempted to deliver the RMS Trojan. The phishing email mimicked the Shevchenkivsky District Court of Kyiv.
“Although they are using phishing and social engineering to get the software into the organizations, once it’s installed, it’s virtually undetectable by traditional threat protection systems because it’s legitimate software. They are still very much active. This is only the beginning of our deep-dive investigation,” Adi Peretz, Senior Strategic Consultant and Head of Research at CyberInt, says.
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Related: Dridex/Locky Operators Unleash New Malware in Recent Attack