Detection rules › Sigma
WSL Child Process Anomaly
Detects uncommon or suspicious child processes spawning from a WSL process. This could indicate an attempt to evade parent/child relationship detections or persistence attempts via cron using WSL
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Evasion | T1202 Indirect Command Execution, T1218 System Binary Proxy Execution |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Security-Auditing | 4688 | A new process has been created. |
Stages and Predicates
Stage 1: selection_parent
or:
ParentImage|endswith: '\wsl.exe'
ParentImage|endswith: '\wslhost.exe'
Stage 2: 1 of selection_children_images
or:
Image|endswith: '\calc.exe'
Image|endswith: '\cmd.exe'
Image|endswith: '\cscript.exe'
Image|endswith: '\mshta.exe'
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'
Image|endswith: '\regsvr32.exe'
Image|endswith: '\rundll32.exe'
Image|endswith: '\wscript.exe'
Stage 3: 1 of selection_children_paths
or:
Image|contains: 'C:\Temp\'
Image|contains: 'C:\Users\Public\'
Image|contains: 'C:\Windows\Temp\'
Image|contains: '\AppData\Local\Temp\'
Image|contains: '\Desktop\'
Image|contains: '\Downloads\'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Image | ends_with |
|
Image | match |
|
ParentImage | ends_with |
|