Suspicious Rundll32 StartW
The following analytic identifies the execution of rundll32.exe with the DLL function names "Start" and "StartW," commonly associated with Cobalt Strike payloads. This detection leverages data from Endpoint Detection…
Description
The following analytic identifies the execution of rundll32.exe with the DLL function names "Start" and "StartW," commonly associated with Cobalt Strike payloads. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions and process metadata. This activity is significant as it often indicates the presence of malicious payloads, such as Cobalt Strike, which can lead to unauthorized code execution. If confirmed malicious, this activity could allow attackers to inject shellcode, escalate privileges, and maintain persistence within the environment.
Detection logic
Detection requirements
- Platform
- Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- crowdstrike_processrollup2sysmon_eventid_1windows_event_log_security_4688
Known benign triggers
- Although unlikely, some legitimate applications may use Start as a function and call it via the command line. Filter as needed.
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 |
|---|---|
| attack.mitre.org/techniques/T1218/011/ | 9 |
| bohops.com/2018/02/26/leveraging-inf-sct-fetch-execute-techniques-for-bypass-evasion-persistence/ | 4 |
| github.com/redcanaryco/atomic-red-team/blob/388942adbd9641f4dfdcf079d7efe9a75ec0ac43/atomics/T1218.011/T1218.011.yaml#L195 | 5 |
| github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.011/T1218.011.md | 5 |
| hstechdocs.helpsystems.com/manuals/cobaltstrike/current/userguide/index.htm#cshid=1036 | 2 |
| lolbas-project.github.io/lolbas/Binaries/Rundll32/ | 7 |
From the source
- At source
- Open at source
- Upstream identifier
- 9319dda5-73f2-4d43-a85a-67ce961bddb7
- Tagged by the source as
- BlackByte RansomwareCobalt StrikeGraceful Wipe Out AttackHellcat RansomwareSuspicious Rundll32 ActivityTrickbotEndpointendpointSplunk 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
- Oct 13, 2026
- Version
- 2