Detection rules › Sigma
Suspicious PsExec Execution - Zeek
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
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Lateral Movement | T1021.002 Remote Services: SMB/Windows Admin Shares |
Rule body yaml
title: Suspicious PsExec Execution - Zeek
id: f1b3a22a-45e6-4004-afb5-4291f9c21166
related:
- id: c462f537-a1e3-41a6-b5fc-b2c2cef9bf82
type: derived
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$'
name|endswith:
- '-stdin'
- '-stdout'
- '-stderr'
filter:
name|startswith: 'PSEXESVC'
condition: selection and not filter
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
selection and not filterStage 1: selection
selection:
path|contains|all:
- '\\'
- '\IPC$'
name|endswith:
- '-stdin'
- '-stdout'
- '-stderr'
Stage 2: not filter
filter:
name|startswith: 'PSEXESVC'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
name | starts_with | PSEXESVC |
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.