Bitsadmin to Uncommon TLD — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Tim Shelton. Source status: test; severity: high. Source dates: 2019-03-07 / 2023-05-17.

{
  "category": "proxy"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 91d52f2772c0618fb20d0e596eca9c7fcf7f64f5070a772b7c2224efb814d902

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: Bitsadmin to Uncommon TLD
id: 9eb68894-7476-4cd6-8752-23b51f5883a7
status: test
description: Detects Bitsadmin connections to domains with uncommon TLDs
references:
    - https://twitter.com/jhencinski/status/1102695118455349248
    - https://isc.sans.edu/forums/diary/Investigating+Microsoft+BITS+Activity/23281/
author: Florian Roth (Nextron Systems), Tim Shelton
date: 2019-03-07
modified: 2023-05-17
tags:
    - attack.command-and-control
    - attack.execution
    - attack.stealth
    - attack.t1071.001
    - attack.persistence
    - attack.t1197
    - attack.s0190
logsource:
    category: proxy
detection:
    selection:
        c-useragent|startswith: 'Microsoft BITS/'
    falsepositives:
        cs-host|endswith:
            - '.com'
            - '.net'
            - '.org'
            - '.scdn.co' # spotify streaming
            - '.sfx.ms' # Microsoft domain, example request: https://oneclient.sfx.ms/PreSignInSettings/Prod/2022-08-15-21-xx-xx/PreSignInSettingsConfig.json
    condition: selection and not falsepositives
falsepositives:
    - Rare programs that use Bitsadmin and update from regional TLDs e.g. .uk or .ca
level: high

Original YAML and metadata in JSON

False positives

• Rare programs that use Bitsadmin and update from regional TLDs e.g. .uk or .ca

Source references

• https://twitter.com/jhencinski/status/1102695118455349248
• https://isc.sans.edu/forums/diary/Investigating+Microsoft+BITS+Activity/23281/