155. Is Abusing Browser Extensions Noisy Enough?

Hello everyone!

I don't often see malicious browser extensions in-the-wild. So this report by Positive Technologies definitely deserves attention.

Despite the fact abusing browser extensions isn't the most common technique, the report shows that installation process is extremely noisy.

For example, the threat actors kill browser-related processes:

var kalee = ["taskkill /F /IM chrome.exe", "taskkill /F /IM msedge.exe", "taskkill /F /IM brave.exe"];

Definitely worth a detector, right?

event_type: "processcreatewin"

AND

proc_file_name: "taskkill.exe"

AND

cmdline: ("chrome" OR "msedge" OR "brave")

Also, the threat actors collect information about the compromised system abusing ipinfo[.]io, for example:

for /f "delims=" %%a in ('powershell -command "(Invoke-RestMethod https://ipinfo.io/json).ip"') do set "IP_PUBLICO=%%a"

Yes, another legitimate service we can use for hunting:

event_type: "dnsreqwin"

AND

dns_rname: "ipinfo.io"

Finally, the adversary modified LNK files for persistence - another very noisy behavior. What does it mean? Even if threat actors use not very common techniques, they still always use lots of other noisy behaviors.

See you tomorrow!

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