Remote Access Tool - ScreenConnect Server Web Shell Execution

Hunt Hypothesis

Detects potential web shell execution from the ScreenConnect server process.

Detection Rule

Sigma (Original)

title: Remote Access Tool - ScreenConnect Server Web Shell Execution
id: b19146a3-25d4-41b4-928b-1e2a92641b1b
status: test
description: Detects potential web shell execution from the ScreenConnect server process.
references:
    - https://blackpointcyber.com/resources/blog/breaking-through-the-screen/
    - https://www.connectwise.com/company/trust/security-bulletins/connectwise-screenconnect-23.9.8
author: Jason Rathbun (Blackpoint Cyber)
date: 2024-02-26
tags:
    - attack.initial-access
    - attack.t1190
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        ParentImage|endswith: '\ScreenConnect.Service.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\csc.exe'
    condition: selection
falsepositives:
    - Unlikely
level: high

KQL (Azure Sentinel)

imProcessCreate
| where (ParentProcessName endswith "\\ScreenConnect.Service.exe" or ActingProcessName endswith "\\ScreenConnect.Service.exe") and (TargetProcessName endswith "\\cmd.exe" or TargetProcessName endswith "\\csc.exe")

Required Data Sources

False Positive Guidance

• Unlikely

MITRE ATT&CK Context

• Tactic: Initial Access
• Technique: T1190 — T1190

References

• https://blackpointcyber.com/resources/blog/breaking-through-the-screen/
• https://www.connectwise.com/company/trust/security-bulletins/connectwise-screenconnect-23.9.8
• SigmaHQ Rule