Suspicious Vsls-Agent Command With AgentExtensionPath Load — Sigma Rule

Rule metadata and linked tags

Author: bohops. Source status: test; severity: medium. Source dates: 2022-10-30 / not supplied.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 44b00f4ffa9a93db21bc72ce6e29b37ce5c92bab4a5f815fa40a3cd09dc7f2cf

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: Suspicious Vsls-Agent Command With AgentExtensionPath Load
id: 43103702-5886-11ed-9b6a-0242ac120002
status: test
description: Detects Microsoft Visual Studio vsls-agent.exe lolbin execution with a suspicious library load using the --agentExtensionPath parameter
references:
    - https://twitter.com/bohops/status/1583916360404729857
author: bohops
date: 2022-10-30
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\vsls-agent.exe'
        CommandLine|contains: '--agentExtensionPath'
    filter:
        CommandLine|contains: 'Microsoft.VisualStudio.LiveShare.Agent.'
    condition: selection and not filter
falsepositives:
    - False positives depend on custom use of vsls-agent.exe
level: medium

Original YAML and metadata in JSON

False positives

• False positives depend on custom use of vsls-agent.exe

Source references

• https://twitter.com/bohops/status/1583916360404729857