Remote Access Tool - MeshAgent Command Execution via MeshCentral

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: @Kostastsale
Source: github.com/SigmaHQ/sigma

Detects the use of MeshAgent to execute commands on the target host, particularly when threat actors might abuse it to execute commands directly. MeshAgent can execute commands on the target host by leveraging win-console to obscure their activities and win-dispatcher to run malicious code through IPC with child processes.

Known false positives

False positives can be found in environments using MeshAgent for remote management, analysis should prioritize the grandparent process, MeshAgent.exe, and scrutinize the resulting child processes triggered by any suspicious interactive commands directed at the target host.

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1219.002` Remote Access Tools: Remote Desktop Software

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Remote Access Tool - MeshAgent Command Execution via MeshCentral
id: 74a2b202-73e0-4693-9a3a-9d36146d0775
status: test
description: |
    Detects the use of MeshAgent to execute commands on the target host, particularly when threat actors might abuse it to execute commands directly.
    MeshAgent can execute commands on the target host by leveraging win-console to obscure their activities and win-dispatcher to run malicious code through IPC with child processes.
references:
    - https://github.com/Ylianst/MeshAgent
    - https://github.com/Ylianst/MeshAgent/blob/52cf129ca43d64743181fbaf940e0b4ddb542a37/modules/win-dispatcher.js#L173
    - https://github.com/Ylianst/MeshAgent/blob/52cf129ca43d64743181fbaf940e0b4ddb542a37/modules/win-info.js#L55
author: '@Kostastsale'
date: 2024-09-22
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        ParentImage|endswith: '\meshagent.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
    condition: selection
falsepositives:
    - False positives can be found in environments using MeshAgent for remote management, analysis should prioritize the grandparent process, MeshAgent.exe, and scrutinize the resulting child processes triggered by any suspicious interactive commands directed at the target host.
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    ParentImage|endswith: '\meshagent.exe'
    Image|endswith:
        - '\cmd.exe'
        - '\powershell.exe'
        - '\pwsh.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\powershell.exe` corpus 179 (sigma 178, kusto 1) `\pwsh.exe` corpus 165 (sigma 164, kusto 1)	`field:"Image" kind:ends_with`
`ParentImage`	ends_with	`\meshagent.exe`	`field:"ParentImage" kind:ends_with value:"\meshagent.exe"`