Detectionmediumtest
Change User Agents with WebRequest
Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.
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Log Source
WindowsPowerShell Script
ProductWindows← raw: windows
CategoryPowerShell Script← raw: ps_script
Definition
Requirements: Script Block Logging must be enabled
Detection Logic
Detection Logic2 selectors
detection:
selection_webrequest:
ScriptBlockText|contains:
- 'Invoke-WebRequest'
- 'Invoke-RestMethod'
- ' irm ' # Space before and after to avoid false positives with 'irm' as a variable
- 'iwr '
selection_useragent:
ScriptBlockText|contains: '-UserAgent '
condition: all of selection_*False Positives
Unknown
False positive likelihood has not been assessed. Additional context may be needed during triage.
References
MITRE ATT&CK
Tactics
Sub-techniques
Rule Metadata
Rule ID
d4488827-73af-4f8d-9244-7b7662ef046e
Status
test
Level
medium
Type
Detection
Created
Sun Jan 23
Modified
Fri Jul 18
Author
Path
rules/windows/powershell/powershell_script/posh_ps_susp_invoke_webrequest_useragent.yml
Raw Tags
attack.command-and-controlattack.t1071.001