↳ GitHub sourceAnalytics ruleMedium
ASR Bypassing Writing Executable Content
Description
The query checks for any file which has been created/written by an Office application and shortly after renamed to one of the deny-listed "executable extensions" which are text files. (e.g. ps1, .js, .vbs).
- Rule type
- Scheduled
- Version
- 1.0.0
- Declared status
- Available
- Query frequency
- 1h
- Query period
- 1h
- Trigger
- gt 0
Declared MITRE coverage
Declared sources
Metadata from the source file. No dependencies inferred from KQL.
Connectors
Data types
KQL query
Original query, unchanged.
let timeframe = 1d;
let executableExtensions = dynamic([".js", ".hta", ".lnk", ".application", ".vb", ".vba", ".vbs", ".ps", ".ps1", ".bat", ".cmd"]);
DeviceFileEvents
| where Timestamp >= ago(timeframe)
| where InitiatingProcessFileName in~ ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe")
| where ActionType == "FileRenamed"
// The mv-apply is less performance compared to doing a full written out !endswith. We kept the mv-apply since We don't hit any limits and get more readable/maintainable code.
| mv-apply ext=executableExtensions to typeof(string) on
(
where PreviousFileName !endswith ext and FileName endswith ext
)
| project-reorder PreviousFileName, FileName
// Begin allow-list.
// End allow-list.
Declared entities
Related content
Links established from declared identifiers and solution manifests.
Source provenance
GitHubDisplayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.
- Commit
9800e51↗- Source identifier
efe4efef-5ca7-4b51-a53e-0e96492ce97a
GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC