A previously undocumented threat actor dubbed YoroTrooper has been targeting government, energy, and international organizations across Europe as part of a cyber espionage campaign that has been active since at least June 2022.
"Information stolen from successful compromises include credentials from multiple applications, browser histories and cookies, system information and screenshots," Cisco Talos researchers Asheer Malhotra and Vitor Ventura said in a Tuesday analysis.
Prominent countries targeted include Azerbaijan, Tajikistan, Kyrgyzstan, Turkmenistan, and other Commonwealth of Independent States (CIS) nations.
The threat actor is believed to be Russian-speaking owing to the victimology patterns and the presence of Cyrillic snippets in some of the implants.
That said, the YoroTrooper intrusion set has been found to exhibit tactical overlaps with the PoetRAT team that was documented in 2020 as leveraging coronavirus-themed baits to strike government and energy sectors in Azerbaijan.
YoroTrooper's data gathering goals are realized through a combination of commodity and open source stealer malware such as Ave Maria (aka Warzone RAT), LodaRAT, Meterpreter, and Stink, with the infection chains using malicious shortcut files (LNKs) and decoy documents wrapped in ZIP or RAR archives that are propagated via spear-phishing.
The LNK files function as simple downloaders to execute an HTA file retrieved from a remote server, which is then used to display a lure PDF document, while stealthily launching a dropper to deliver a custom stealer that uses Telegram as an exfiltration channel.
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The use of LodaRAT is notable as it indicates that the malware is being employed by multiple operators despite its attribution to another group called Kasablanka, which has also been observed distributing Ave Maria in recent campaigns targeting Russia.
Other auxiliary tools deployed by YoroTrooper consist of reverse shells and a C-based custom keylogger that's capable of recording keystrokes and saving them to a file on disk.
"It is worth noting that while this campaign began with the distribution of commodity malware such as Ave Maria and LodaRAT, it has evolved significantly to include Python-based malware," the researchers said.
"This highlights an increase in the efforts the threat actor is putting in, likely derived from successful breaches during the course of the campaign."