godmode_sigma_rule.yml

#    _____        __  __  ___        __      
#   / ___/__  ___/ / /  |/  /__  ___/ /__    
#  / (_ / _ \/ _  / / /|_/ / _ \/ _  / -_)   
#  \___/\___/\_,_/ /_/  /_/\___/\_,_/\__/_   
#    / __(_)__ ___ _  ___ _  / _ \__ __/ /__ 
#   _\ \/ / _ `/  ' \/ _ `/ / , _/ // / / -_)
#  /___/_/\_, /_/_/_/\_,_/ /_/|_|\_,_/_/\__/ 
#        /___/ IDDQD                              
#
#  Florian Roth
#  May 2020
#  v0.3
#
#  A Proof-of-Concept with the most effective search queries

title: Godmode Sigma Rule
id: def6caac-a999-4fc9-8800-cfeff700ba98
description: 'PoC rule to detect malicious activity - following the principle: if you had only one shot, what would you look for?'
status: experimental
author: Florian Roth
date: 2019/12/22
modified: 2020/05/18
level: high
action: global
---
logsource:
    category: process_creation
    product: windows
detection:
    # Different suspicious or malicious command line parameters
    selection_plain:
        CommandLine|contains:
            - ' -NoP '  # Often used in malicious PowerShell commands
            - ' -W Hidden '  # Often used in malicious PowerShell commands
            - ' -decode '  # Used with certutil
            - ' /decode '  # Used with certutil 
            - ' -e* JAB'  # PowerShell encoded commands
            - ' -e* SUVYI'  # PowerShell encoded commands
            - ' -e* SQBFAFgA'  # PowerShell encoded commands
            - ' -e* aWV4I'  # PowerShell encoded commands
            - ' -e* IAB'  # PowerShell encoded commands
            - ' -e* PAA'  # PowerShell encoded commands
            - ' -e* aQBlAHgA'  # PowerShell encoded commands
            - 'vssadmin delete shadows'  # Ransomware
            - 'reg SAVE HKLM\SAM'  # save registry SAM - syskey extraction
            - ' -ma '  # ProcDump
            - 'Microsoft\Windows\CurrentVersion\Run'  # Run key in command line - often in combination with REG ADD
            - '.downloadstring('  # PowerShell download command
            - '.downloadfile('  # PowerShell download command
            - ' /ticket:'  # Rubeus
            - ' sekurlsa'  # Mimikatz
            - ' p::d '  # Mimikatz 
            - ';iex('  # PowerShell IEX
            - 'schtasks* /create *AppData'  # Scheduled task creation pointing to AppData
            - ' comsvcs.dll,MiniDump'  # Process dumping method apart from procdump
            - ' comsvcs.dll,#24'  # Process dumping method apart from procdump
    selection_parent_child:
        ParentImage|contains:
            # Office Dropper Detection
            - '\WINWORD.EXE'
            - '\EXCEL.EXE'
            - '\POWERPNT.exe'
            - '\MSPUB.exe'
            - '\VISIO.exe'
            - '\OUTLOOK.EXE'
        Image|contains:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wscript.exe'
            - '\cscript.exe'
            - '\schtasks.exe'
            - '*\scrcons.exe'
            - '\regsvr32.exe'
            - '\hh.exe'
            - '\wmic.exe'
            - '\mshta.exe'
            - '\msiexec.exe'
            - '\forfiles.exe'
            - '\AppData\'
    selection_webshells:
        Image|contains:
            - '\apache*'
            - '\tomcat*'
            - '\w3wp.exe'
            - '\php-cgi.exe'
            - '\nginx.exe'
            - '\httpd.exe'
        CommandLine|contains:
            - 'whoami'
            - 'net user '
            - 'ping -n '
            - 'systeminfo'
            - '&cd&echo'
            - 'cd /d '  # https://www.computerhope.com/cdhlp.htm
    # Running whoami as LOCAL_SYSTEM (usually after privilege escalation)
    selection_whoami:
        Image|contains: '\whoami.exe'
        User: 'NT AUTHORITY\SYSTEM' 
    condition: 1 of them
---
logsource:
    product: windows
    service: sysmon
detection:
    selection_file_creation:
        EventID: 11
        TargetFilename|contains: 
            - '.dmp'  # dump process memory
            - 'Desktop\how'  # Ransomware
            - 'Desktop\decrypt'  # Ransomware
    selection_registry_modifications:
        EventID:
            - 12
            - 13
        TargetObject|contains: 
            - 'UserInitMprLogonScript'  # persistence
            - '\CurrentVersion\Image File Execution Options\'  # persistence
    selection_registry_run:
        EventID:
            - 12
            - 13
        TargetObject|contains: 
            - '\Microsoft\Windows\CurrentVersion\Run\'  # persistence
            - '\Microsoft\Windows\CurrentVersion\RunOnce\'   # persistence
        Details|contains:
            - 'AppData'
            - '\Users\Public\'
            - '\Temp\'
            - 'powershell'
            - 'wscript'
            - 'cscript'
    condition: 1 of them
---
logsource:
    product: windows
    service: system
detection:
    # Malicious service installs
    selection:
        EventID: 7045
        ServiceName|contains: 
            - 'WCESERVICE'
            - 'WCE SERVICE'
            - 'winexesvc'
            - 'DumpSvc'
            - 'pwdump'
            - 'gsecdump'
            - 'cachedump'
    condition:
        1 of them