296. Hunting for Caminho Loader Behaviors

Hello everyone!

Today we'll look at a few examples of behaviors related to Caminho Loader, which employs Least Significant Bit (LSB) steganography to conceal .NET payloads within image files hosted on legitimate platforms.

For example, according to the report, the adversary leveraged malicious JS files to download the second-stage script from paste[.]ee. We can transform it into a hunting query and look for wscript.exe attempts to connect to paste[.]ee:

event_type: "dnsreqwin"

AND

dns_rname: "paste.ee"

AND

proc_file_path: "wscript.exe"

The next stage, a heavily obfuscated PowerShell script, downloads a steganographic image file from archive[.]org. This behavior can also be easily transformed into a hunting query:

event_type: "dnsreqwin"

AND

dns_rname: "archive.org"

AND

proc_file_path: "powershell.exe"

Check the report for more detection and hunting opportunities!

See you tomorrow!

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