Windows PowerShell Script TabExpansion Direct Call
Detects specific indicators associated with the execution of the TabExpansion internal function in PowerShell. Calling this function directly is not normal and can be indicative of malicious activity such as…
Description
Detects specific indicators associated with the execution of the TabExpansion internal function in PowerShell. Calling this function directly is not normal and can be indicative of malicious activity such as TabShell. Due to the way PowerShell internals work it can be used in conjunction with directory transversal to load any PowerShell functions even in a sandboxed session. False positives could include legitimate usage of the TabExpansion function but calling it directly is very rare.
Detection logic
Detection requirements
- Platform
- LinuxmacOSWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- powershell_script_block_logging_4104
Known benign triggers
- Legitimate use of the TabExpansion function is rare but possible. Filter alerts if direct calls are from trusted administrative or development activities.
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 |
|---|---|
| blog.viettelcybersecurity.com/tabshell-owassrf/ | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- d36a09b3-35ac-4d6f-964a-39fd337abc2f
- Tagged by the source as
- Malicious PowerShellEndpointendpointSplunk 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