Detection rules › Sigma
Uncommon Userinit Child Process
Detects uncommon "userinit.exe" child processes, which could be a sign of uncommon shells or login scripts used for persistence.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1037.001 Boot or Logon Initialization Scripts: Logon Script (Windows) |
| Privilege Escalation | T1037.001 Boot or Logon Initialization Scripts: Logon Script (Windows) |
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
ParentImage|endswith: '\userinit.exe'
Stage 2: not 1 of filter_main_explorer
Image|endswith: ':\WINDOWS\explorer.exe'
Stage 3: not 1 of filter_optional_*
or:
CommandLine: PowerShell.exe
CommandLine|contains: UsrLogon.cmd
CommandLine|contains: netlogon.bat
Image|endswith: ':\Program Files (x86)\Citrix\HDX\bin\cmstart.exe'
Image|endswith: ':\Program Files (x86)\Citrix\HDX\bin\icast.exe'
Image|endswith: ':\Program Files (x86)\Citrix\System32\icast.exe'
Image|endswith: ':\Program Files\Citrix\HDX\bin\cmstart.exe'
Image|endswith: ':\Program Files\Citrix\HDX\bin\icast.exe'
Image|endswith: ':\Program Files\Citrix\System32\icast.exe'
Image|endswith: ':\Windows\SysWOW64\proquota.exe'
Image|endswith: ':\Windows\System32\proquota.exe'
Image: null
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 |
|---|---|---|
CommandLine | eq |
|
CommandLine | match |
|
Image | ends_with |
|
ParentImage | ends_with |
|