Detection rules › Splunk
Rundll32.exe as Parent Process (Windows Event Log)
Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218.011 System Binary Proxy Execution: Rundll32 |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
id: '5850.6131'
title: Rundll32.exe as Parent Process
description: 'Adversaries may abuse rundll32.exe to proxy execution of malicious code.
Using rundll32.exe, may avoid triggering security tools that may not monitor execution
of the rundll32.exe process because of allowlists or false positives from normal
operations. Rundll32.exe is commonly associated with executing DLL payloads. Threat
Actor Association: MuddyWater, TA505, Wizard Spider - Software Association: Bazar,
Clop, Conti, Quantum, Rhysida, Trickbot'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<") TERM(rundll32) | regex parent_process_name="(?i)(rundll32)" |
table _time, host, user parent_*, process, process_*, signature_id | bin span=1s
| stats values(*) as * by _time, host '
techniques:
- defense-evasion:system binary proxy execution:rundll32
technique_id:
- T1218.011
data_category:
- Process command-line parameters
- Windows event logs
references:
- https://redcanary.com/threat-detection-report/techniques/rundll32/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<") TERM(rundll32)
Stage 2: regex
| regex parent_process_name="(?i)(rundll32)"
Stage 3: table
| table _time, host, user parent_*, process, process_*, signature_id
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
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 |
|---|---|---|
EventCode | eq |
|
parent_process_name | regex_match |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>4688<" |
| 1 | TERM |
| 1 | rundll32 |