Researchers Dissect Activity of Cybercrime Group Targeting Aviation, Other Sectors

Proofpoint’s security researchers have taken a deep dive into the activity of TA2541, a threat actor targeting the aerospace, aviation, defense, manufacturing and transportation sectors for years.

Active since at least 2017, the adversary has been observed employing aviation-, transportation- and travel-related themes to infect targets with various remote access Trojans (RATs).

Unlike other threat actors that rely on current events as lures in their attacks, TA2541 has shown consistent tactics, techniques, and procedures (TTPs) over time, typically sending phishing emails that carry macro-enabled Word attachments to deploy malicious payloads.

In recent attacks, however, the group has started to frequently use links to payloads hosted on cloud services, including Google Drive, OneDrive, GitHub, Pastetext, and Sharetext. Recent Google Drive URLs led to an obfuscated Visual Basic Script (VBS) file meant to fetch a payload from other platforms.

The attacks employ PowerShell scripts and rely on Windows Management Instrumentation (WMI) to query security products that the adversary attempts to disable. TA2541 also harvests system information prior to persistently installing RATs.

The group typically sends more than 10,000 messages at a time as part of its attacks, targeting hundreds of organizations in North America, Europe, and the Middle East.

[READ: Nigerian Threat Actor Targeting Aviation Industry Since 2018]

“Proofpoint assesses TA2541 is a cybercriminal threat actor due to its use of specific commodity malware, broad targeting with high volume messages, and command and control infrastructure,” Proofpoint’s security researchers say in a new report.

Starting late 2021, the threat actor was also observed leveraging Discord URLs leading to a compressed file meant to download either AgentTesla or Imminent Monitor. In some cases, compressed executables were sent to the intended victims.

TA2541 has used various commodity malware families since 2017, but appears to prefer AsyncRAT at the moment. NetWire, Parallax, and WSH RAT were also used in numerous attacks, along with Revenge RAT, vjw0rm, Luminosity Link, njRAT, and others.

“All the malware used by TA2541 can be used for information gathering purposes and to gain remote control of an infected machine. At this time, Proofpoint does not know what the threat actor’s ultimate goals and objectives are once it achieves initial compromise,” the researchers note.

To date, the threat actor has been observed launching attacks on thousands of organizations across the aerospace, aviation, defense, manufacturing and transportation sectors, without targeting specific roles and functions.

“TA2541 remains a consistent, active cybercrime threat, especially to entities in its most frequently targeted sectors. Proofpoint assesses with high confidence this threat actor will continue using the same TTPs observed in historic activity with minimal change to its lure themes, delivery, and installation,” Proofpoint says.

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