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Invoke-Obfuscation Obfuscated IEX Invocation - Security

Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the code block linked in the references

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Launch
Daniel Bohannon ( / ), oscd.communityCreated Fri Nov 08Updated Sun Nov 27fd0f5778-d3cb-4c9a-9695-66759d04702awindows
Log Source
Windowssecurity
ProductWindows← raw: windows
Servicesecurity← raw: security

Definition

The 'System Security Extension' audit subcategory need to be enabled to log the EID 4697

Detection Logic
Detection Logic2 selectors
detection:
    selection_eid:
        EventID: 4697
    selection_servicefilename:
        - ServiceFileName|re: '\$PSHome\[\s*\d{1,3}\s*\]\s*\+\s*\$PSHome\['
        - ServiceFileName|re: '\$ShellId\[\s*\d{1,3}\s*\]\s*\+\s*\$ShellId\['
        - ServiceFileName|re: '\$env:Public\[\s*\d{1,3}\s*\]\s*\+\s*\$env:Public\['
        - ServiceFileName|re: '\$env:ComSpec\[(\s*\d{1,3}\s*,){2}'
        - ServiceFileName|re: '\\*mdr\*\W\s*\)\.Name'
        - ServiceFileName|re: '\$VerbosePreference\.ToString\('
        - ServiceFileName|re: '\String\]\s*\$VerbosePreference'
    condition: all of selection_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.

References
1
Resolving title…
github.com
MITRE ATT&CK
Related Rules
DerivedDetectionhigh

Invoke-Obfuscation Obfuscated IEX Invocation - System

Detects all variations of obfuscated powershell IEX invocation code generated by Invoke-Obfuscation framework from the code block linked in the references

This rule was derived from the related rule - both detect similar activity with different scope.

Rule Metadata
Rule ID
fd0f5778-d3cb-4c9a-9695-66759d04702a
Status
test
Level
high
Type
Detection
Created
Fri Nov 08
Modified
Sun Nov 27
Author
Daniel Bohannon ( / ), oscd.community
Path
rules/windows/builtin/security/win_security_invoke_obfuscation_obfuscated_iex_services_security.yml
Raw Tags
attack.defense-evasionattack.t1027
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