Detection rules › Splunk

Windows Defender ASR Audit Events

Author
Michael Haag, Splunk
Source
upstream

This detection searches for Windows Defender ASR audit events. ASR is a feature of Windows Defender Exploit Guard that prevents actions and apps that are typically used by exploit-seeking malware to infect machines. ASR rules are applied to processes and applications. When a process or application attempts to perform an action that is blocked by an ASR rule, an event is generated. This detection searches for ASR audit events that are generated when a process or application attempts to perform an action that would be blocked by an ASR rule, but is allowed to proceed for auditing purposes.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566.001 Phishing: Spearphishing Attachment, T1566.002 Phishing: Spearphishing Link
ExecutionT1059 Command and Scripting Interpreter

Event coverage

ProviderEvent IDTitle
Windows-Defender1122
Windows-Defender1125
Windows-Defender1126
Windows-Defender1132
Windows-Defender1134

Stages and Predicates

Stage 1: search

search EventCode IN (1122, 1125, 1126, 1132, 1134)

Stage 2: stats

stats BY host, Process_Name, Target_Commandline, Path, ID, EventCode

Stage 3: lookup

lookup <lookup> ASR_Rule, ID

Stage 4: fillnull

fillnull

Stage 5: search

search

Stage 6: search

search

Stage 7: rename

rename

Stage 8: 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
EventCodein
  • 1122 corpus 2 (splunk 2)
  • 1125 corpus 2 (splunk 2)
  • 1126 corpus 3 (splunk 3)
  • 1132 corpus 2 (splunk 2)
  • 1134 corpus 2 (splunk 2)

Neighbors

Often fire together

Rules that target events appearing in the same incident timelines. They pattern-match on adjacent steps of the same TTP, so an alert from one is often paired with alerts from these. Useful for triage context and for assembling chained-detection rules.

Share event IDs (chain-detection candidates)

Rules that observe the same Windows event-ID pairs as this one. If you're authoring a multi-stage / sequence rule that spans these events, these are the existing detections that already cover one or both endpoints.