Download From Suspicious TLD - Whitelist — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: test; severity: low. Source dates: 2017-03-13 / 2023-05-18.

{
  "category": "proxy"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: e2dec419ead113a47a636578abd563d399e684e37961e855f79c15483ec138e0

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: Download From Suspicious TLD - Whitelist
id: b5de2919-b74a-4805-91a7-5049accbaefe
related:
    - id: 00d0b5ab-1f55-4120-8e83-487c0a7baf19
      type: similar
status: test
description: Detects executable downloads from suspicious remote systems
references:
    - Internal Research
author: Florian Roth (Nextron Systems)
date: 2017-03-13
modified: 2023-05-18
tags:
    - attack.initial-access
    - attack.t1566
    - attack.execution
    - attack.t1203
    - attack.t1204.002
logsource:
    category: proxy
detection:
    selection:
        c-uri-extension:
            - 'exe'
            - 'vbs'
            - 'bat'
            - 'rar'
            - 'ps1'
            - 'doc'
            - 'docm'
            - 'xls'
            - 'xlsm'
            - 'pptm'
            - 'rtf'
            - 'hta'
            - 'dll'
            - 'ws'
            - 'wsf'
            - 'sct'
            - 'zip'
            # If you want to add more extensions - see https://docs.google.com/spreadsheets/d/1TWS238xacAto-fLKh1n5uTsdijWdCEsGIM0Y0Hvmc5g/
    filter:
        cs-host|endswith:
            - '.com'
            - '.org'
            - '.net'
            - '.edu'
            - '.gov'
            - '.uk'
            - '.ca'
            - '.de'
            - '.jp'
            - '.fr'
            - '.au'
            - '.us'
            - '.ch'
            - '.it'
            - '.nl'
            - '.se'
            - '.no'
            - '.es'
            # Extend this list as needed
    condition: selection and not filter
falsepositives:
    - All kind of software downloads
level: low

Original YAML and metadata in JSON

False positives

• All kind of software downloads

Source references

• Internal Research (source note; no public URL supplied)