Detection rules › Sigma

New User Created Via Net.EXE With Never Expire Option

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

Detects creation of local users via the net.exe command with the option "never expire"

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1136.001 Create Account: Local Account

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: New User Created Via Net.EXE With Never Expire Option
id: b9f0e6f5-09b4-4358-bae4-08408705bd5c
related:
    - id: cd219ff3-fa99-45d4-8380-a7d15116c6dc
      type: derived
status: test
description: Detects creation of local users via the net.exe command with the option "never expire"
references:
    - https://thedfirreport.com/2022/07/11/select-xmrig-from-sqlserver/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-12
modified: 2023-02-21
tags:
    - attack.persistence
    - attack.t1136.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\net.exe'
              - '\net1.exe'
        - OriginalFileName:
              - 'net.exe'
              - 'net1.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'user'
            - 'add'
            - 'expires:never'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith:
          - '\net.exe'
          - '\net1.exe'
    - OriginalFileName:
          - 'net.exe'
          - 'net1.exe'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains|all:
        - 'user'
        - 'add'
        - 'expires:never'

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)
  • expires:never
  • user corpus 17 (sigma 11, splunk 4, chronicle 2)
Imageends_with
  • \net.exe corpus 49 (sigma 49)
  • \net1.exe corpus 47 (sigma 47)
OriginalFileNameeq
  • net.exe corpus 28 (sigma 19, elastic 7, splunk 2)
  • net1.exe corpus 44 (sigma 19, splunk 19, elastic 6)