Registry-Free Process Scope COR_PROFILER
Adversaries may leverage the COR_PROFILER environment variable to hijack the execution flow of programs that load the .NET CLR. The COR_PROFILER is a .NET Framework feature which allows developers to specify an unmanaged (or external of .NET) profiling DLL to be loaded into each .NET process that loads the Common Language Runtime (CLR). These profiliers are designed to monitor, troubleshoot, and debug managed code executed by the .NET CLR. (Citation: Microsoft Profiling Mar 2017) (Citation: Microsoft COR_PROFILER Feb 2013)
Sigma rule (View on GitHub)
1title: Registry-Free Process Scope COR_PROFILER
2id: 23590215-4702-4a70-8805-8dc9e58314a2
3status: test
4description: |
5 Adversaries may leverage the COR_PROFILER environment variable to hijack the execution flow of programs that load the .NET CLR.
6 The COR_PROFILER is a .NET Framework feature which allows developers to specify an unmanaged (or external of .NET) profiling DLL to be loaded into each .NET process that loads the Common Language Runtime (CLR).
7 These profiliers are designed to monitor, troubleshoot, and debug managed code executed by the .NET CLR.
8 (Citation: Microsoft Profiling Mar 2017)
9 (Citation: Microsoft COR_PROFILER Feb 2013)
10references:
11 - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1574.012/T1574.012.md#atomic-test-3---registry-free-process-scope-cor_profiler
12author: frack113
13date: 2021-12-30
14tags:
15 - attack.privilege-escalation
16 - attack.persistence
17 - attack.execution
18 - attack.stealth
19 - attack.t1574.012
20logsource:
21 product: windows
22 category: ps_script
23 definition: 'Requirements: Script Block Logging must be enabled'
24detection:
25 selection:
26 ScriptBlockText|contains|all:
27 - '$env:COR_ENABLE_PROFILING'
28 - '$env:COR_PROFILER'
29 - '$env:COR_PROFILER_PATH'
30 condition: selection
31falsepositives:
32 - Legitimate administrative script
33level: medium
References
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