ISO File Created Within Temp Folders — Sigma Rule

Rule metadata and linked tags

Author: @sam0x90. Source status: test; severity: high. Source dates: 2022-07-30 / not supplied.

{
  "category": "file_event",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 876543fc15b268b4468a6533ac0cdd164a9af9e6c5cd0143fed9800c981d46cf

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: ISO File Created Within Temp Folders
id: 2f9356ae-bf43-41b8-b858-4496d83b2acb
status: test
description: Detects the creation of a ISO file in the Outlook temp folder or in the Appdata temp folder. Typical of Qakbot TTP from end-July 2022.
references:
    - https://twitter.com/Sam0x90/status/1552011547974696960
    - https://securityaffairs.co/wordpress/133680/malware/dll-sideloading-spread-qakbot.html
    - https://github.com/redcanaryco/atomic-red-team/blob/0f229c0e42bfe7ca736a14023836d65baa941ed2/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image
author: '@sam0x90'
date: 2022-07-30
tags:
    - attack.initial-access
    - attack.t1566.001
logsource:
    category: file_event
    product: windows
detection:
    selection_1:
        TargetFilename|contains|all:
            - '\AppData\Local\Temp\'
            - '.zip\'
        TargetFilename|endswith: '.iso'
    selection_2:
        TargetFilename|contains: '\AppData\Local\Microsoft\Windows\INetCache\Content.Outlook\'
        TargetFilename|endswith: '.iso'
    condition: 1 of selection*
falsepositives:
    - Potential FP by sysadmin opening a zip file containing a legitimate ISO file
level: high

Original YAML and metadata in JSON

False positives

• Potential FP by sysadmin opening a zip file containing a legitimate ISO file

Source references

• https://twitter.com/Sam0x90/status/1552011547974696960
• https://securityaffairs.co/wordpress/133680/malware/dll-sideloading-spread-qakbot.html
• https://github.com/redcanaryco/atomic-red-team/blob/0f229c0e42bfe7ca736a14023836d65baa941ed2/atomics/T1553.005/T1553.005.md#atomic-test-1---mount-iso-image