A new secret stash for “fileless” malware

In February 2022 we observed the technique of putting the shellcode into Windows event logs for the first time “in the wild” during the malicious campaign. It allows the “fileless” last stage Trojan to be hidden from plain sight in the file system. Such attention to the event logs in the campaign isn’t limited to storing shellcodes. Dropper modules also patch Windows native API functions, related to event tracing (ETW) and anti-malware scan interface (AMSI), to make the infection process stealthier.

Besides event logs there are numerous other techniques in the actor’s toolset. Among them let us distinguish how the actor takes initial recon into consideration while developing the next malicious stages: the C2 web domain name mimicking the legitimate one and the name in use belonging to the existing and software used by the victim. For hosting the attacker uses virtual private servers on Linode, Namecheap, DreamVPS.

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Source: Trend Micro