Detection rules › Sigma

User creation via commandline

Severity
high
Log source
product windows, category process_creation
Author
mdecrevoisier
Source
github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker attempts to create a user via commandline.

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: User creation via commandline
description: Detects scenarios where an attacker attempts to create a user via commandline.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0003-Persistence/T1136-Create%20account
- https://blogs.jpcert.or.jp/en/2016/01/windows-commands-abused-by-attackers.html
- https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
- https://attack.mitre.org/software/S0039/
- https://regex101.com/r/S6vTNM/1
tags:
- attack.persistence
- attack.t1136.001
- attack.t1136.002
author: mdecrevoisier
logsource:
  product: windows
  category: process_creation
detection:
  selection: # Full command example: 'net user <username> <password> /ADD'
    NewProcessName|endswith:
      - \net1.exe
      - \net.exe
    CommandLine|contains|all:
      - net
      - user
      - add
  condition: selection
falsepositives:
- Pentest
- Administrator activity
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
  NewProcessName|endswith:
    - \net1.exe
    - \net.exe
  CommandLine|contains|all:
    - net
    - user
    - add

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
CommandLinematch
  • add corpus 34 (sigma 26, splunk 4, chronicle 2, kusto 2)
  • net corpus 7 (sigma 7)
  • user corpus 17 (sigma 11, splunk 4, chronicle 2)
NewProcessNameends_with
  • \net.exe corpus 49 (sigma 49)
  • \net1.exe corpus 47 (sigma 47)