Creation of a Diagcab

Status: test
Severity: medium
Log source: category file_event, product windows
Author: frack113
Source: github.com/SigmaHQ/sigma

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)

Known false positives

Legitimate microsoft diagcab

MITRE ATT&CK coverage

Tactic	Techniques
Resource Development	No specific technique

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 11: FileCreate

Rule body

title: Creation of a Diagcab
id: 3d0ed417-3d94-4963-a562-4a92c940656a
status: test
description: 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: frack113
date: 2022-06-08
tags:
    - attack.resource-development
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith: '.diagcab'
    condition: selection
falsepositives:
    - Legitimate microsoft diagcab
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    TargetFilename|endswith: '.diagcab'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`TargetFilename`	ends_with	`.diagcab` corpus 2 (sigma 2)	`field:"TargetFilename" kind:ends_with value:".diagcab"`