sigmahighHunting

PsExec/PAExec Escalation to LOCAL SYSTEM

Detects suspicious commandline flags used by PsExec and PAExec to escalate a command line to LOCAL_SYSTEM rights

MITRE ATT&CK

resource-development

Detection Query

selection_sys:
  CommandLine|contains|windash:
    - " -s cmd"
    - " -s -i cmd"
    - " -i -s cmd"
    - " -s pwsh"
    - " -s -i pwsh"
    - " -i -s pwsh"
    - " -s powershell"
    - " -s -i powershell"
    - " -i -s powershell"
selection_other:
  CommandLine|contains:
    - psexec
    - paexec
    - accepteula
condition: all of selection_*

Author

Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)

Created

2021-11-23

Data Sources

windowsProcess Creation Events

Platforms

windows

References

Tags

attack.resource-developmentattack.t1587.001

Raw Content

title: PsExec/PAExec Escalation to LOCAL SYSTEM
id: 8834e2f7-6b4b-4f09-8906-d2276470ee23
related:
    - id: 207b0396-3689-42d9-8399-4222658efc99 # Generic rule based on similar cli flags
      type: similar
status: test
description: Detects suspicious commandline flags used by PsExec and PAExec to escalate a command line to LOCAL_SYSTEM rights
references:
    - https://learn.microsoft.com/en-us/sysinternals/downloads/psexec
    - https://www.poweradmin.com/paexec/
    - https://www.fireeye.com/blog/threat-research/2020/10/kegtap-and-singlemalt-with-a-ransomware-chaser.html
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2021-11-23
modified: 2024-03-05
tags:
    - attack.resource-development
    - attack.t1587.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_sys: # Escalation to LOCAL_SYSTEM
        CommandLine|contains|windash:
            # Note that you don't need to add the ".exe" part when using psexec/paexec
            # The "-" can also be replaced with "/"
            # The order of args isn't important
            # "cmd" can be replaced by "powershell", "pwsh" or any other console like software
            - ' -s cmd'
            - ' -s -i cmd'
            - ' -i -s cmd'
            # Pwsh (For PowerShell 7)
            - ' -s pwsh'
            - ' -s -i pwsh'
            - ' -i -s pwsh'
            # PowerShell (For PowerShell 5)
            - ' -s powershell'
            - ' -s -i powershell'
            - ' -i -s powershell'
    selection_other:
        CommandLine|contains:
            - 'psexec'
            - 'paexec'
            - 'accepteula'
    condition: all of selection_*
falsepositives:
    - Admins that use PsExec or PAExec to escalate to the SYSTEM account for maintenance purposes (rare)
    - Users that debug Microsoft Intune issues using the commands mentioned in the official documentation; see https://learn.microsoft.com/en-us/mem/intune/apps/intune-management-extension
level: high