Out of sight but not invisible: Defeating fileless malware

Dynamic AMSI log generated during the execution of the Sharpshooter technique in the two malicious scripts

Using this AMSI-aided detection, Windows Defender ATP disrupted two distinct malware campaigns in June, as well as the steady hum of daily activities. Sample Windows Defender ATP alert showing how detection of the Sharpshooter technique by Windows Defender AV is surfaced in Windows Defender Security Center

We analyzed the script and extracted the fileless payload, a very stealthy . Antivirus capabilities in Windows Defender ATP blocking legitimate regsvr32 tool abused to download and run a malicious remote script

The term “fileless” suggests that a threat that does not come in a file, such as a backdoor that lives only in the memory of a machine.

Source: www.microsoft.com