Detection rules › Sigma

Win Susp Computer Name Containing Samtheadmin

Status
test
Severity
critical
Log source
product windows, service security
Author
elhoim
Source
github.com/SigmaHQ/sigma

Detects suspicious computer name samtheadmin-{1..100}$ generated by hacktool

MITRE ATT&CK coverage

TacticTechniques
Initial Access
Persistence
Privilege Escalation
Stealth

Rule body

title: Win Susp Computer Name Containing Samtheadmin
id: 39698b3f-da92-4bc6-bfb5-645a98386e45
status: test
description: Detects suspicious computer name samtheadmin-{1..100}$ generated by hacktool
references:
    - https://twitter.com/malmoeb/status/1511760068743766026
    - https://github.com/helloexp/0day/blob/614227a7b9beb0e91e7e2c6a5e532e6f7a8e883c/00-CVE_EXP/CVE-2021-42287/sam-the-admin/sam_the_admin.py
author: elhoim
date: 2022-09-09
modified: 2023-01-04
tags:
    - attack.initial-access
    - cve.2021-42278
    - cve.2021-42287
    - attack.persistence
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1078
logsource:
    service: security
    product: windows
detection:
    # Not adding an EventID on purpose to try to match on any event in security (including use of account), not just 4741 (computer account created)
    selection1:
        SamAccountName|startswith: 'SAMTHEADMIN-'
        SamAccountName|endswith: '$'
    selection2:
        TargetUserName|startswith: 'SAMTHEADMIN-'
        TargetUserName|endswith: '$'
    condition: 1 of selection*
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

1 of selection*

Stage 1: selection1

selection1:
    SamAccountName|startswith: 'SAMTHEADMIN-'
    SamAccountName|endswith: '$'

Stage 2: selection2

selection2:
    TargetUserName|startswith: 'SAMTHEADMIN-'
    TargetUserName|endswith: '$'

Indicators

These rows show field, operator, and value matches.