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Detection rules › Sigma

Rorschach Ransomware Execution Activity

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

Detects Rorschach ransomware execution activity

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell, T1059.003 Command and Scripting Interpreter: Windows Command Shell

Event coverage

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

Rule body yaml

title: Rorschach Ransomware Execution Activity
id: 0e9e6c63-1350-48c4-9fa1-7ccb235edc68
status: test
description: Detects Rorschach ransomware execution activity
references:
    - https://research.checkpoint.com/2023/rorschach-a-new-sophisticated-and-fast-ransomware/
author: X__Junior (Nextron Systems)
date: 2023-04-04
modified: 2023-04-22
tags:
    - attack.execution
    - attack.t1059.003
    - attack.t1059.001
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\bcdedit.exe'
            - '\net.exe'
            - '\net1.exe'
            - '\netsh.exe'
            - '\wevtutil.exe'
            - '\vssadmin.exe'
        CommandLine|contains: '11111111'
    condition: selection
falsepositives:
    - Unlikely
level: critical

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith:
        - '\bcdedit.exe'
        - '\net.exe'
        - '\net1.exe'
        - '\netsh.exe'
        - '\wevtutil.exe'
        - '\vssadmin.exe'
    CommandLine|contains: '11111111'

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
  • 11111111
Imageends_with
  • \bcdedit.exe corpus 5 (sigma 5)
  • \net.exe corpus 49 (sigma 49)
  • \net1.exe corpus 47 (sigma 47)
  • \netsh.exe corpus 28 (sigma 28)
  • \vssadmin.exe corpus 6 (sigma 6)
  • \wevtutil.exe corpus 9 (sigma 9)