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Detection rules › Sigma

Phishing Pattern ISO in Archive

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects cases in which an ISO files is opend within an archiver like 7Zip or Winrar, which is a sign of phishing as threat actors put small ISO files in archives as email attachments to bypass certain filters and protective measures (mark of web)

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566 Phishing

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Phishing Pattern ISO in Archive
id: fcdf69e5-a3d3-452a-9724-26f2308bf2b1
status: test
description: Detects cases in which an ISO files is opend within an archiver like 7Zip or Winrar, which is a sign of phishing as threat actors put small ISO files in archives as email attachments to bypass certain filters and protective measures (mark of web)
references:
    - https://twitter.com/1ZRR4H/status/1534259727059787783
    - https://app.any.run/tasks/e1fe6a62-bce8-4323-a49a-63795d9afd5d/
author: Florian Roth (Nextron Systems)
date: 2022-06-07
tags:
    - attack.initial-access
    - attack.t1566
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith:
            - '\Winrar.exe'
            - '\7zFM.exe'
            - '\peazip.exe'
        Image|endswith:
            - '\isoburn.exe'
            - '\PowerISO.exe'
            - '\ImgBurn.exe'
    condition: selection
falsepositives:
    - Legitimate cases in which archives contain ISO or IMG files and the user opens the archive and the image via clicking and not extraction
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentImage|endswith:
        - '\Winrar.exe'
        - '\7zFM.exe'
        - '\peazip.exe'
    Image|endswith:
        - '\isoburn.exe'
        - '\PowerISO.exe'
        - '\ImgBurn.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • \ImgBurn.exe
  • \PowerISO.exe
  • \isoburn.exe
ParentImageends_with
  • \7zFM.exe corpus 2 (sigma 2)
  • \Winrar.exe corpus 5 (sigma 5)
  • \peazip.exe