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Detection rules › Sigma

Potential Suspicious Child Process Of 3CXDesktopApp

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

Detects potential suspicious child processes of "3CXDesktopApp.exe". Which could be related to the 3CXDesktopApp supply chain compromise

MITRE ATT&CK coverage

TacticTechniques
StealthT1218 System Binary Proxy Execution

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Potential Suspicious Child Process Of 3CXDesktopApp
id: 63f3605b-979f-48c2-b7cc-7f90523fed88
related:
    - id: 3c4b3bbf-36b4-470c-b6cf-f07e8b1c7e26 # Proxy C2
      type: similar
    - id: 76bc1601-9546-4b75-9419-06e0e8d10651 # Proxy GH
      type: similar
    - id: bd03a0dc-5d93-49eb-b2e8-2dfd268600f8 # DNS C2
      type: similar
    - id: 51eecf75-d069-43c7-9ea2-63f75499edd4 # net_connection C2
      type: similar
    - id: 93bbde78-dc86-4e73-9ffc-ff8a384ca89c # ProcCreation Exec
      type: similar
    - id: e7581747-1e44-4d4b-85a6-0db0b4a00f2a # ProcCreation Update
      type: similar
    - id: d0b65ad3-e945-435e-a7a9-438e62dd48e9 # ImageLoad
      type: similar
status: test
description: Detects potential suspicious child processes of "3CXDesktopApp.exe". Which could be related to the 3CXDesktopApp supply chain compromise
references:
    - https://www.reddit.com/r/crowdstrike/comments/125r3uu/20230329_situational_awareness_crowdstrike/
    - https://www.crowdstrike.com/blog/crowdstrike-detects-and-prevents-active-intrusion-campaign-targeting-3cxdesktopapp-customers/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-03-29
tags:
    - attack.command-and-control
    - attack.execution
    - attack.stealth
    - attack.t1218
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\3CXDesktopApp.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\mshta.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\regsvr32.exe'
            - '\rundll32.exe'
            - '\wscript.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentImage|endswith: '\3CXDesktopApp.exe'
    Image|endswith:
        - '\cmd.exe'
        - '\cscript.exe'
        - '\mshta.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\wscript.exe'

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
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)
  • \cscript.exe corpus 73 (sigma 73)
  • \mshta.exe corpus 67 (sigma 67)
  • \powershell.exe corpus 182 (sigma 182)
  • \pwsh.exe corpus 168 (sigma 168)
  • \regsvr32.exe corpus 65 (sigma 65)
  • \rundll32.exe corpus 95 (sigma 95)
  • \wscript.exe corpus 75 (sigma 75)
ParentImageends_with
  • \3CXDesktopApp.exe