Suspicious CLR Load Into Mstsc RDP Client

ATT&CK techniques

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Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
- T1055Process Injection
Defense Evasion
- T1055Process Injection
Cred Access
- T1056.001Keylogging
Discovery
Lateral Movement
Collection
- T1056.001Keylogging
C2
Exfiltration
Impact

What it detects

This rule detects the .NET CLR being loaded into the Windows Remote Desktop client mstsc.exe, which does not normally host managed code. In the WithSecure Windows Lab 3 an unsigned DLL is injected into mstsc.exe and pulls in clr.dll to hook credential APIs and capture RDP credentials to disk. This anomalous module load reveals in-process injection targeting a trusted native binary.

Reporting behind it

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Suspicious CLR Load Into Mstsc RDP Client

Pivot detection · T1055 · 9 related

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