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Office ASR rule triggered from browser spawned office process.

Description

The attacker sends a spearphishing email to a user. The email contains a link which points to a website that eventually presents the user a download of an MS Office document. This document contains a malicious macro. The macro triggers one of the ASR rules. This detection looks for Office ASR violations triggered by an Office document opened from a browser. Note: be aware that you need to have the proper ASR rules enabled for this detection to work.
Rule type
Scheduled
Version
1.0.1
Declared status
Available
Query frequency
5m
Query period
5m
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.

// Add your own browsers here as well. 
let browsers = dynamic(["iexplore.exe", "chrome.exe", "firefox.exe", "msedge.exe"]);
DeviceEvents
| where ActionType contains "Office"
| where InitiatingProcessFileName in~ (browsers) or InitiatingProcessParentFileName in~ (browsers)
// Ignore docx, xlsx and pptx files. These don't contain macros.
| where not(FileName endswith ".docx" or FileName endswith ".xlsx" or FileName endswith ".pptx")

Declared entities

AccountHostProcess

Related content

Links established from declared identifiers and solution manifests.

Source provenance

GitHub

Displayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.

Source identifier
30580043-2451-4d35-b49f-065728529f4a
Additional source files 2Solutions/FalconFriday/Analytic Rules/OfficeASRFromBrowser.yamlsource ↗Solutions/FalconFriday/Data/Solution_FalconFriday.jsonsolution-membership ↗
GSTEP / CATALOG TRACKING

Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC

GSTEP sync dates, separate from the source content’s publication dates.