Techniques
Sample rules
Powershell Creating Thread Mutex
- source: splunk
- technicques:
- T1027.005
- T1059.001
Description
The following analytic detects the execution of PowerShell scripts using the mutex function via EventCode 4104. This detection leverages PowerShell Script Block Logging to identify scripts that create thread mutexes, a technique often used in obfuscated scripts to ensure only one instance runs on a compromised machine. This activity is significant as it may indicate the presence of sophisticated malware or persistence mechanisms. If confirmed malicious, the attacker could maintain exclusive control over a process, potentially leading to further exploitation or persistence within the environment.
Detection logic
`powershell` EventCode=4104 ScriptBlockText = "*Threading.Mutex*"
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID
| rename Computer as dest
|rename UserID as user
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `powershell_creating_thread_mutex_filter`