Detection rules › Sigma

Remote Access Tool - ScreenConnect Potential Suspicious Remote Command Execution

Status
test
Severity
medium
Log source
category process_creation, product windows
Author
Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), @Kostastsale
Source
github.com/SigmaHQ/sigma

Detects potentially suspicious child processes launched via the ScreenConnect client service.

Known false positives

  • If the script being executed make use of any of the utilities mentioned in the detection then they should filtered out or allowed.

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Remote Access Tool - ScreenConnect Potential Suspicious Remote Command Execution
id: 7b582f1a-b318-4c6a-bf4e-66fe49bf55a5
related:
    - id: d1a401ab-8c47-4e86-a7d8-2460b6a53e4a
      type: derived
status: test
description: |
    Detects potentially suspicious child processes launched via the ScreenConnect client service.
references:
    - https://www.mandiant.com/resources/telegram-malware-iranian-espionage
    - https://docs.connectwise.com/ConnectWise_Control_Documentation/Get_started/Host_client/View_menu/Backstage_mode
    - https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708
    - https://www.trendmicro.com/en_us/research/24/b/threat-actor-groups-including-black-basta-are-exploiting-recent-.html
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), @Kostastsale
date: 2022-02-25
modified: 2024-02-28
tags:
    - attack.command-and-control
    - attack.t1219.002
logsource:
    product: windows
    category: process_creation
detection:
    selection:
        ParentCommandLine|contains|all:
            - ':\Windows\TEMP\ScreenConnect\'
            - 'run.cmd'
        Image|endswith:
            - '\bitsadmin.exe'
            - '\cmd.exe'
            - '\curl.exe'
            - '\dllhost.exe'
            - '\net.exe'
            - '\nltest.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\rundll32.exe'
            - '\wevtutil.exe'
    condition: selection
falsepositives:
    - If the script being executed make use of any of the utilities mentioned in the detection then they should filtered out or allowed.
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentCommandLine|contains|all:
        - ':\Windows\TEMP\ScreenConnect\'
        - 'run.cmd'
    Image|endswith:
        - '\bitsadmin.exe'
        - '\cmd.exe'
        - '\curl.exe'
        - '\dllhost.exe'
        - '\net.exe'
        - '\nltest.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\rundll32.exe'
        - '\wevtutil.exe'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Imageends_with
  • \bitsadmin.exe corpus 29 (sigma 29)
  • \cmd.exe corpus 130 (sigma 130)
  • \curl.exe corpus 31 (sigma 31)
  • \dllhost.exe corpus 11 (sigma 11)
  • \net.exe corpus 49 (sigma 49)
  • \nltest.exe corpus 9 (sigma 9)
  • \powershell.exe corpus 179 (sigma 178, kusto 1)
  • \pwsh.exe corpus 165 (sigma 164, kusto 1)
  • \rundll32.exe corpus 94 (sigma 94)
  • \wevtutil.exe corpus 9 (sigma 9)
field:"Image" kind:ends_with
ParentCommandLinematch
  • :\Windows\TEMP\ScreenConnect\
  • run.cmd
field:"ParentCommandLine" kind:match