Detection rules › Sigma

PsExec Tool Execution From Suspicious Locations - PipeName

Status
test
Severity
medium
Log source
product windows, category pipe_created
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects PsExec default pipe creation where the image executed is located in a suspicious location. Which could indicate that the tool is being used in an attack

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: PsExec Tool Execution From Suspicious Locations - PipeName
id: 41504465-5e3a-4a5b-a5b4-2a0baadd4463
related:
    - id: f3f3a972-f982-40ad-b63c-bca6afdfad7c
      type: derived
status: test
description: Detects PsExec default pipe creation where the image executed is located in a suspicious location. Which could indicate that the tool is being used in an attack
references:
    - https://www.jpcert.or.jp/english/pub/sr/ir_research.html
    - https://jpcertcc.github.io/ToolAnalysisResultSheet
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-04
modified: 2023-09-20
tags:
    - attack.execution
    - attack.t1569.002
    - attack.s0029
logsource:
    category: pipe_created
    product: windows
    definition: 'Note that you have to configure logging for Named Pipe Events in Sysmon config (Event ID 17 and Event ID 18). The basic configuration is in popular sysmon configuration (https://github.com/SwiftOnSecurity/sysmon-config), but it is worth verifying. You can also use other repo, e.g. https://github.com/Neo23x0/sysmon-config, https://github.com/olafhartong/sysmon-modular. How to test detection? You can check powershell script from this site https://svch0st.medium.com/guide-to-named-pipes-and-hunting-for-cobalt-strike-pipes-dc46b2c5f575'
detection:
    selection:
        PipeName: '\PSEXESVC'
        Image|contains: # Add or remove locations depending on how and if you execute Psexec in your env
            - ':\Users\Public\'
            - ':\Windows\Temp\'
            - '\AppData\Local\Temp\'
            - '\Desktop\'
            - '\Downloads\'
    condition: selection
falsepositives:
    - Rare legitimate use of psexec from the locations mentioned above. This will require initial tuning based on your environment.
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    PipeName: '\PSEXESVC'
    Image|contains:
        - ':\Users\Public\'
        - ':\Windows\Temp\'
        - '\AppData\Local\Temp\'
        - '\Desktop\'
        - '\Downloads\'

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
Imagematch
  • :\Users\Public\ corpus 15 (sigma 15)
  • :\Windows\Temp\ corpus 9 (sigma 9)
  • \AppData\Local\Temp\ corpus 11 (sigma 11)
  • \Desktop\ corpus 7 (sigma 7)
  • \Downloads\ corpus 10 (sigma 10)
PipeNameeq
  • \PSEXESVC corpus 2 (sigma 2)