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Detection rules › Sigma

CobaltStrike Service Installations - System

Status
test
Severity
critical
Log source
product windows, service system
Author
Florian Roth (Nextron Systems), Wojciech Lesicki
Source
github.com/SigmaHQ/sigma

Detects known malicious service installs that appear in cases in which a Cobalt Strike beacon elevates privileges or lateral movement

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1569.002 System Services: Service Execution
PersistenceT1543.003 Create or Modify System Process: Windows Service
Privilege EscalationT1543.003 Create or Modify System Process: Windows Service
Lateral MovementT1021.002 Remote Services: SMB/Windows Admin Shares

Event coverage

ProviderEvent
Service-Control-ManagerEvent ID 7045

Rule body yaml

title: CobaltStrike Service Installations - System
id: 5a105d34-05fc-401e-8553-272b45c1522d
status: test
description: Detects known malicious service installs that appear in cases in which a Cobalt Strike beacon elevates privileges or lateral movement
references:
    - https://www.sans.org/webcasts/119395
    - https://www.crowdstrike.com/blog/getting-the-bacon-from-cobalt-strike-beacon/
    - https://thedfirreport.com/2021/08/29/cobalt-strike-a-defenders-guide/
author: Florian Roth (Nextron Systems), Wojciech Lesicki
date: 2021-05-26
modified: 2022-11-27
tags:
    - attack.persistence
    - attack.execution
    - attack.privilege-escalation
    - attack.lateral-movement
    - attack.t1021.002
    - attack.t1543.003
    - attack.t1569.002
logsource:
    product: windows
    service: system
detection:
    selection_id:
        Provider_Name: 'Service Control Manager'
        EventID: 7045
    selection1:
        ImagePath|contains|all:
            - 'ADMIN$'
            - '.exe'
    selection2:
        ImagePath|contains|all:
            - '%COMSPEC%'
            - 'start'
            - 'powershell'
    selection3:
        ImagePath|contains: 'powershell -nop -w hidden -encodedcommand'
    selection4:
        ImagePath|base64offset|contains: "IEX (New-Object Net.Webclient).DownloadString('http://127.0.0.1:"
    condition: selection_id and (selection1 or selection2 or selection3 or selection4)
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

selection_id and (selection1 or selection2 or selection3 or selection4)

Stage 1: selection_id

selection_id:
    Provider_Name: 'Service Control Manager'
    EventID: 7045

Stage 2: selection1

selection1:
    ImagePath|contains|all:
        - 'ADMIN$'
        - '.exe'

Stage 3: selection2

selection2:
    ImagePath|contains|all:
        - '%COMSPEC%'
        - 'start'
        - 'powershell'

Stage 4: selection3

selection3:
    ImagePath|contains: 'powershell -nop -w hidden -encodedcommand'

Stage 5: selection4

selection4:
    ImagePath|base64offset|contains: "IEX (New-Object Net.Webclient).DownloadString('http://127.0.0.1:"

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
ImagePathmatch
  • %COMSPEC% corpus 2 (sigma 2)
  • .exe
  • ADMIN$
  • IEX (New-Object Net.Webclient).DownloadString('http://127.0.0.1: transforms: base64offset
  • powershell corpus 5 (sigma 5)
  • powershell -nop -w hidden -encodedcommand
  • start
Provider_Nameeq
  • Service Control Manager corpus 50 (sigma 50)