MediumSplunk security content Michael Haag +1

Suspicious Rundll32 dllregisterserver

Description

The following analytic detects the execution of rundll32.exe with the DllRegisterServer command to load a DLL. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions and process details. This activity is significant as it may indicate an attempt to register a malicious DLL, which can be a method for code execution or persistence. If confirmed malicious, an attacker could gain unauthorized code execution, escalate privileges, or maintain persistence within the environment, posing a severe security risk.

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_processrollup2 sysmon_eventid_1 windows_event_log_security_4688

Known benign triggers

This is likely to produce false positives and will require some filtering. Tune the query by adding command line paths to known good DLLs, or filtering based on parent process names.

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
attack.mitre.org/techniques/T1218/011/	Taxonomy	9
docs.microsoft.com/en-us/windows/win32/api/olectl/nf-olectl-dllregisterserver?redirectedfrom=MSDN	Product documentation	Only this detection cites it
github.com/pan-unit42/tweets/blob/master/2020-12-10-IOCs-from-Ursnif-infection-with-Delf-variant.txt	Tool	Only this detection cites it
github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.011/T1218.011.md	Detection test	5
lolbas-project.github.io/lolbas/Binaries/Rundll32/	Tool	7
symantec-enterprise-blogs.security.com/blogs/threat-intelligence/seedworm-apt-iran-middle-east	Unclassified	2from 2 sources
www.crowdstrike.com/blog/duck-hunting-with-falcon-complete-qakbot-zip-based-campaign/	Security research	Only this detection cites it

Detection rules

Suspicious Rundll32 dllregisterserver

Description

Detection logic

Detection requirements

Known benign triggers

MITRE ATT&CK mappings

References

From the source

Licence

Authorship

Detection rules