225. MucorAgent Uses Component Object Model Hijacking for Persistence

Hello everyone!

I think everyone is tired of common persistence mechanisms. Startup folder, Run key, scheduled tasks, services... Let's look at something more interesting - Event Triggered Execution: Component Object Model Hijacking (T1546.015).

As always, we need a real-world example. And I got one for you - MucorAgent. The malware abuses reg.exe to modify registry and hijack the CLSID:

reg add HKEY_USERS\<SID>\SOFTWARE\Classes\CLSID\{de434264-8fe9-4c0b-a83b-89ebeebff78e}\InprocServer32 /t REG_SZ /d "C:\\Windows\\System32\\mscoree.dll" /F 

reg add HKEY_USERS\<SID>\SOFTWARE\Classes\CLSID\{de434264-8fe9-4c0b-a83b-89ebeebff78e}\InprocServer32 /v Assembly /t REG_SZ /d "TaskLauncher, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" /F 

reg add HKEY_USERS\<SID>\SOFTWARE\Classes\CLSID\{de434264-8fe9-4c0b-a83b-89ebeebff78e}\InprocServer32 /v Class /t REG_SZ /d "TaskLauncher.TaskHandler" /F 

reg add HKEY_USERS\<SID>\SOFTWARE\Classes\CLSID\{de434264-8fe9-4c0b-a83b-89ebeebff78e}\InprocServer32 /v CodeBase /t REG_SZ /d "C:\\ProgramData\\Intel\\Logs\\Data\\TaskLauncher.dll" /F 

reg add HKEY_USERS\<SID>\SOFTWARE\Classes\CLSID\{de434264-8fe9-4c0b-a83b-89ebeebff78e}\InprocServer32 /v RuntimeVersion /t REG_SZ /d "v4.0.30319" /F 

According to the report, the adversary also targeted the following CLSID: {613fba38-a3df-4ab8-9674-5604984a299a}.

So, here we can hunt for suspicious registry modifications:

event_type: "processcreatewin"

AND

proc_file_path: "reg.exe"

AND

cmdline: "InprocServer32"

See you tomorrow!

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