Malicious PowerShell Process - Execution Policy Bypass
The following analytic detects PowerShell processes initiated with parameters that bypass the local execution policy for scripts. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on…
Description
The following analytic detects PowerShell processes initiated with parameters that bypass the local execution policy for scripts. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions containing specific flags like "-ex" or "bypass." This activity is significant because bypassing execution policies is a common tactic used by attackers to run malicious scripts undetected. If confirmed malicious, this could allow an attacker to execute arbitrary code, potentially leading to further system compromise, data exfiltration, or persistent access within the environment.
Detection logic
Detection requirements
- Platform
- Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- crowdstrike_processrollup2sysmon_eventid_1windows_event_log_security_4688
Known benign triggers
- There may be legitimate reasons to bypass the PowerShell execution policy. The PowerShell script being run with this parameter should be validated to ensure that it is legitimate.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| www.microsoft.com/en-us/security/blog/2023/05/24/volt-typhoon-targets-us-critical-infrastructure-with-living-off-the-land-techniques/ | 20 |
From the source
- At source
- Open at source
- Upstream identifier
- 9be56c82-b1cc-4318-87eb-d138afaaca39
- Tagged by the source as
- 0bj3ctivity StealerAPT37 Rustonotto and FadeStealerAsyncRATBlankGrabber StealerChina-Nexus Threat ActivityDarkCrystal RATDHS Report TA18-074AHAFNIUM GroupMuddyWaterSalt TyphoonStarland RAT CampaignVolt TyphoonXWormEndpointendpointSplunk CloudSplunk EnterpriseSplunk Enterprise Securityendpoint
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1