Powershell DNSExfiltration — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: high. Source dates: 2022-01-07 / not supplied.

{
  "product": "windows",
  "category": "ps_script",
  "definition": "Requirements: Script Block Logging must be enabled"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6512497a3cc7ed82ef8543454d5fdd9c83835df7ad0a403acf2550ff10a62b2a

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: Powershell DNSExfiltration
id: d59d7842-9a21-4bc6-ba98-64bfe0091355
status: test
description: DNSExfiltrator allows for transferring (exfiltrate) a file over a DNS request covert channel
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1048/T1048.md#atomic-test-3---dnsexfiltration-doh
    - https://github.com/Arno0x/DNSExfiltrator
author: frack113
date: 2022-01-07
tags:
    - attack.exfiltration
    - attack.t1048
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection_cmdlet:
        - ScriptBlockText|contains: 'Invoke-DNSExfiltrator'
        - ScriptBlockText|contains|all:
              - ' -i '
              - ' -d '
              - ' -p '
              - ' -doh '
              - ' -t '
    condition: selection_cmdlet
falsepositives:
    - Legitimate script
level: high

Original YAML and metadata in JSON

False positives

• Legitimate script

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1048/T1048.md#atomic-test-3---dnsexfiltration-doh
• https://github.com/Arno0x/DNSExfiltrator