Detection rules › Splunk

Windows Unsigned DLL Side-Loading In Same Process Path

Author
Teoderick Contreras, Splunk
Source
upstream

This detection identifies unsigned DLLs loaded through DLL side-loading with same file path with the process loaded the DLL, a technique observed in DarkGate malware. This detection monitors DLL loading, verifies signatures, and flags unsigned DLLs. Suspicious file paths and known executable associations are checked. Detecting such suspicious DLLs is crucial in preventing privilege escalation attacks and other potential security breaches. Regular security assessments, thorough monitoring, and implementing security best practices are essential in safeguarding systems from such threats.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1574.001 Hijack Execution Flow: DLL
Privilege EscalationT1574.001 Hijack Execution Flow: DLL
Defense EvasionT1574.001 Hijack Execution Flow: DLL

Event coverage

ProviderEvent IDTitle
Sysmon7Image loaded

Stages and Predicates

Stage 1: search

search NOT (NOT ImageLoaded IN ("*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*") Image IN ("*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*")) EventCode=7 SignatureStatus!="Valid" Signed=false

Stage 2: rex

rex field=Image ...

Stage 3: rex

rex field=ImageLoaded ...

Stage 4: where

where ImageFolderPath=

Stage 5: stats

stats BY Image, ImageLoaded, dest, loaded_file, loaded_file_path, process_exec, process_guid, process_hash, process_id, process_name, process_path, service_dll_signature_exists, service_dll_signature_verified, signature, signature_id, user_id, vendor_product

Stage 6: search

search

Stage 7: search

search

Stage 8: search

search `macro`

Exclusions

Top-level NOT(...) conjuncts — predicates this rule actively suppresses.

StageFieldKindExcluded values
1ImageLoadedin"*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*"
2Imagein"*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*"

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
  • 7 corpus 35 (splunk 35)
ImageLoadedin
  • "*:\\windows\\system32\\*" corpus 2 (splunk 2)
  • "*:\\windows\\syswow64\\*" corpus 2 (splunk 2)
  • "c:\\Program Files*"
SignatureStatusne
  • Valid corpus 2 (splunk 2)
Signedeq
  • false corpus 8 (sigma 4, splunk 4)

Neighbors

Broader alternatives (more inclusive than this rule)

These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.