PUA - CsExec Execution

Hunt Hypothesis

Detects the use of the lesser known remote execution tool named CsExec a PsExec alternative

Detection Rule

Sigma (Original)

title: PUA - CsExec Execution
id: d08a2711-ee8b-4323-bdec-b7d85e892b31
status: test
description: Detects the use of the lesser known remote execution tool named CsExec a PsExec alternative
references:
    - https://github.com/malcomvetter/CSExec
    - https://www.microsoft.com/security/blog/2022/05/09/ransomware-as-a-service-understanding-the-cybercrime-gig-economy-and-how-to-protect-yourself/
author: Florian Roth (Nextron Systems)
date: 2022-08-22
modified: 2023-02-21
tags:
    - attack.resource-development
    - attack.t1587.001
    - attack.execution
    - attack.t1569.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\csexec.exe'
    selection_pe:
        Description: 'csexec'
    condition: 1 of selection*
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessName endswith "\\csexec.exe" or TargetProcessFileDescription =~ "csexec"

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Resource Development
• Tactic: Execution
• Technique: T1587.001 — T1587.001
• Technique: T1569.002 — T1569.002

References

• https://github.com/malcomvetter/CSExec
• https://www.microsoft.com/security/blog/2022/05/09/ransomware-as-a-service-understanding-the-cybercrime-gig-economy-and-how-to-protect-yourself/
• SigmaHQ Rule