Detection rules › Splunk
Windows Defender ASR Rules Stacking
The following analytic identifies security events from Microsoft Defender, focusing on Exploit Guard and Attack Surface Reduction (ASR) features. It detects Event IDs 1121, 1126, 1131, and 1133 for blocked operations, and Event IDs 1122, 1125, 1132, and 1134 for audit logs. Event ID 1129 indicates user overrides, while Event ID 5007 signals configuration changes. This detection uses a lookup to correlate ASR rule GUIDs with descriptive names. Monitoring these events is crucial for identifying unauthorized operations, potential security breaches, and policy enforcement issues. If confirmed malicious, attackers could bypass security measures, execute unauthorized actions, or alter system configurations.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1566.001 Phishing: Spearphishing Attachment, T1566.002 Phishing: Spearphishing Link |
| Execution | T1059 Command and Scripting Interpreter |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Windows-Defender | 1121 | |
| Windows-Defender | 1122 | |
| Windows-Defender | 1125 | |
| Windows-Defender | 1126 | |
| Windows-Defender | 1129 | |
| Windows-Defender | 1131 | |
| Windows-Defender | 1132 | |
| Windows-Defender | 1133 | |
| Windows-Defender | 1134 | |
| Windows-Defender | 5007 |
Stages and Predicates
Stage 1: search
search EventCode IN (1121, 1122, 1125, 1126, 1129, 1131, 1132, 1133, 1134, 5007)
Stage 2: stats
stats BY host, Parent_Commandline, Process_Name, 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.
| Field | Kind | Values |
|---|---|---|
EventCode | in |
|
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.