Detection rules › Sigma

OpenEDR Spawning Command Shell

Status
experimental
Severity
medium
Log source
product windows, category process_creation
Author
@kostastsale
Source
github.com/SigmaHQ/sigma

Detects the OpenEDR ssh-shellhost.exe spawning a command shell (cmd.exe) or PowerShell with PTY (pseudo-terminal) capabilities. This may indicate remote command execution through OpenEDR's remote management features, which could be legitimate administrative activity or potential abuse of the remote access tool. Threat actors may leverage OpenEDR's remote shell capabilities to execute commands on compromised systems, facilitating lateral movement or other command-and-control operations.

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: OpenEDR Spawning Command Shell
id: 7f3a9c2d-4e8b-4a7f-9d3e-5c6f8a9b2e1d
status: experimental
description: |
    Detects the OpenEDR ssh-shellhost.exe spawning a command shell (cmd.exe) or PowerShell with PTY (pseudo-terminal) capabilities.
    This may indicate remote command execution through OpenEDR's remote management features, which could be legitimate administrative activity or potential abuse of the remote access tool.
    Threat actors may leverage OpenEDR's remote shell capabilities to execute commands on compromised systems, facilitating lateral movement or other command-and-control operations.
author: '@kostastsale'
date: 2026-02-19
references:
    - https://kostas-ts.medium.com/detecting-abuse-of-openedrs-permissive-edr-trial-a-security-researcher-s-perspective-fc55bf53972c
tags:
    - attack.execution
    - attack.t1059.003
    - attack.lateral-movement
    - attack.t1021.004
    - attack.command-and-control
    - attack.t1219
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        ParentImage|endswith: '\ITSMService.exe'
        Image|endswith: '\ssh-shellhost.exe'
        CommandLine|contains: '--pty'
    selection_cli_shell:
        CommandLine|contains:
            - 'bash'
            - 'cmd'
            - 'powershell'
            - 'pwsh'
    condition: all of selection_*
falsepositives:
    - Legitimate use of OpenEDR for remote command execution
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    ParentImage|endswith: '\ITSMService.exe'
    Image|endswith: '\ssh-shellhost.exe'
    CommandLine|contains: '--pty'

Stage 2: selection_cli_shell

selection_cli_shell:
    CommandLine|contains:
        - 'bash'
        - 'cmd'
        - 'powershell'
        - 'pwsh'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
CommandLinematch
  • --pty
  • bash corpus 5 (sigma 5)
  • cmd corpus 8 (sigma 8)
  • powershell corpus 25 (sigma 24, chronicle 1)
  • pwsh corpus 7 (sigma 7)
Imageends_with
  • \ssh-shellhost.exe
ParentImageends_with
  • \ITSMService.exe