078. Detecting AMOS Stealer's Virtual Machine Checks

Hello everyone! We haven't talked about macOS stealers for some time. Definitely, this threat as a trend, so let's talk about AMOS.


Recently I spotted an interesting anti-analysis procedure leveraged by this stealer:

osascript -e "set memData to do shell script \"system_profiler SPMemoryDataType\"

if memData contains \"QEMU\" or memData contains \"VMware\" then

    do shell script \"exit 42\"

else

    do shell script \"exit 0\"

end if"

The malware checks for the presence of virtual machines and exits with error code 42 if it detects any.

We can detect such behavior this way:

event_type: "processcreatemac"

AND

proc_file_name: "osascript"

AND

cmdline: "SPMemoryDataType" AND ("QEMU" OR "VMware")

If you want to learn more about AMOS behaviors, here's a sample for you.

See you tomorrow!

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