Suspicious Creation of a Diagcab (via file_event)

This rule detects the creation of diagcab file, which could be caused by some legitimate installer or is a sign of exploitation (review the filename and its location)

SigmamediumWindowsv1

sigma

suspicious-creation-of-a-diagcab-via-file-event

title: Suspicious Creation of a Diagcab (via file_event)
id: b6c3c3a9-61d9-5c86-8218-a87163e8f444
status: stable
description: This rule detects the creation of diagcab file, which could be caused by some legitimate installer or is a sign of exploitation (review the filename and its location)
references:
    - https://threadreaderapp.com/thread/1533879688141086720.html
author: Huntrule Team
date: 2026-03-15
tags:
    - attack.resource-development
    - attack.execution
    - attack.t1203
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith: '.diagcab'
    condition: selection
falsepositives:
    - Unknown
level: medium

Known false positives

Unknown

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.