detection.wiki

Detection rules › Sigma

ISO File Created Within Temp Folders

Status
test
Severity
high
Log source
category file_event, product windows
Author
@sam0x90
Source
github.com/SigmaHQ/sigma

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.

Known false positives

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

MITRE ATT&CK coverage

TacticTechniques
Initial Access

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 11: FileCreate

Rule body

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

Stages and Predicates

Stage 0: condition

1 of selection*

Stage 1: selection_1

selection_1:
    TargetFilename|contains|all:
        - '\AppData\Local\Temp\'
        - '.zip\'
    TargetFilename|endswith: '.iso'

Stage 2: selection_2

selection_2:
    TargetFilename|contains: '\AppData\Local\Microsoft\Windows\INetCache\Content.Outlook\'
    TargetFilename|endswith: '.iso'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
TargetFilenameends_with
  • .iso corpus 5 (sigma 5)
field:"TargetFilename" kind:ends_with value:".iso"
TargetFilenamematch
  • .zip\
  • \AppData\Local\Microsoft\Windows\INetCache\Content.Outlook\
  • \AppData\Local\Temp\ corpus 8 (sigma 8)
field:"TargetFilename" kind:match