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Detection rules › Sigma

Potential BlackByte Ransomware Activity

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

Detects command line patterns used by BlackByte ransomware in different operations

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell
StealthT1140 Deobfuscate/Decode Files or Information
ImpactT1485 Data Destruction, T1498 Network Denial of Service

Event coverage

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

Rule body yaml

title: Potential BlackByte Ransomware Activity
id: 999e8307-a775-4d5f-addc-4855632335be
status: test
description: Detects command line patterns used by BlackByte ransomware in different operations
references:
    - https://redcanary.com/blog/blackbyte-ransomware/
author: Florian Roth (Nextron Systems)
date: 2022-02-25
modified: 2023-02-08
tags:
    - attack.execution
    - attack.impact
    - attack.stealth
    - attack.t1485
    - attack.t1498
    - attack.t1059.001
    - attack.t1140
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_1:
        Image|startswith: 'C:\Users\Public\'
        CommandLine|contains: ' -single '
    selection_2:
        CommandLine|contains:
            - 'del C:\Windows\System32\Taskmgr.exe'
            - ';Set-Service -StartupType Disabled $'
            - 'powershell -command "$x =[System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String('
            - ' do start wordpad.exe /p '
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

1 of selection_*

Stage 1: selection_1

selection_1:
    Image|startswith: 'C:\Users\Public\'
    CommandLine|contains: ' -single '

Stage 2: selection_2

selection_2:
    CommandLine|contains:
        - 'del C:\Windows\System32\Taskmgr.exe'
        - ';Set-Service -StartupType Disabled $'
        - 'powershell -command "$x =[System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String('
        - ' do start wordpad.exe /p '

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
  • -single
  • do start wordpad.exe /p
  • ;Set-Service -StartupType Disabled $
  • del C:\Windows\System32\Taskmgr.exe
  • powershell -command "$x =[System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String(
Imagestarts_with
  • C:\Users\Public\ corpus 2 (sigma 1, elastic 1)