Suspicious PsExec Execution - Zeek

Title: Suspicious PsExec Execution - Zeek
Status: test
Description:detects execution of psexec or paexec with renamed service name, this rule helps to filter out the noise if psexec is used for legit purposes or if attacker uses a different psexec client other than sysinternal one
References:
  -https://web.archive.org/web/20230329171218/https://blog.menasec.net/2019/02/threat-hunting-3-detecting-psexec.html
Author: Samir Bousseaden, @neu5ron, Tim Shelton
Date: 2020-04-02
modified:2022-12-27
Tags:

• -'attack.lateral-movement'
• -'attack.t1021.002'

Logsource:

• product: zeek
• service: smb_files

Detection:
  selection:
    path|contains|all:
      -'\\'
      -'\IPC$'

    name|endswith:
      -'-stdin'
      -'-stdout'
      -'-stderr'

  filter:
    name|startswith: 'PSEXESVC'
  condition:selection and not filter
Falsepositives:
  -Unknown
Level: high