Malware dll side-loading using system32 executables

I observed a couple of malware samples that did multiple dll side-loading by copying (assumed) system32 exes to a random path in appdata\roaming and dropping their own malicious dll.


  • sigverif.exe -> version.dll
  • rdpinit.exe
  • netplwiz.exe -> netplwiz.dll
  • applysettingstemplatecatalog.exe -> activeds.dll
  • computerdefaults.exe
  • msdt.exe -> duser.dll
  • utilman.exe -> dui70.dll


Assuming you have EDR data in Splunk here is a simple detection example to look for the executable and negate the normal path.




There are some other paths to negate as well but I want to keep it simple here.

Related post to detect ANY system32 executable running from a non-standard path.


Mitre ATT&CK ID T1073

References:
http://www.hexacorn.com/blog/2016/03/10/beyond-good-ol-run-key-part-36/

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