Detection rules › Splunk

Rundll32 Create Remote Thread To A Process

Author
Teoderick Contreras, Splunk
Source
upstream

The following analytic detects the creation of a remote thread by rundll32.exe into another process. It leverages Sysmon EventCode 8 logs, specifically monitoring SourceImage and TargetImage fields. This activity is significant as it is a common technique used by malware, such as IcedID, to execute malicious code within legitimate processes, aiding in defense evasion and data theft. If confirmed malicious, this behavior could allow an attacker to execute arbitrary code, escalate privileges, and exfiltrate sensitive information from the compromised host.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
Defense EvasionT1055 Process Injection

Event coverage

ProviderEvent IDTitle
Sysmon8CreateRemoteThread

Stages and Predicates

Stage 1: search

search EventCode=8 SourceImage="*\\rundll32.exe" TargetImage="*.exe"

Stage 2: stats

stats BY EventID, Guid, NewThreadId, ProcessID, SecurityID, SourceImage, SourceProcessGuid, SourceProcessId, StartAddress, StartFunction, StartModule, TargetImage, TargetProcessGuid, TargetProcessId, UserID, dest, parent_process_exec, parent_process_guid, parent_process_id, parent_process_name, parent_process_path, process_exec, process_guid, process_id, process_name, process_path, signature, signature_id, user_id, vendor_product

Stage 3: search

search

Stage 4: search

search

Stage 5: search

search `macro`

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.

FieldKindValues
EventCodeeq
  • 8 corpus 8 (splunk 8)
SourceImageeq
  • "*\\rundll32.exe" corpus 2 (splunk 2)
TargetImageeq
  • "*.exe" corpus 2 (splunk 2)