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Detection rules › Sigma

REvil Kaseya Incident Malware Patterns

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

Detects process command line patterns and locations used by REvil group in Kaseya incident (can also match on other malware)

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter

Event coverage

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

Rule body yaml

title: REvil Kaseya Incident Malware Patterns
id: 5de632bc-7fbd-4c8a-944a-fce55c59eae5
status: test
description: Detects process command line patterns and locations used by REvil group in Kaseya incident (can also match on other malware)
references:
    - https://community.sophos.com/b/security-blog/posts/active-ransomware-attack-on-kaseya-customers
    - https://www.joesandbox.com/analysis/443736/0/html
    - https://doublepulsar.com/kaseya-supply-chain-attack-delivers-mass-ransomware-event-to-us-companies-76e4ec6ec64b
    - https://therecord.media/revil-ransomware-executes-supply-chain-attack-via-malicious-kaseya-update/
    - https://blog.truesec.com/2021/07/04/kaseya-supply-chain-attack-targeting-msps-to-deliver-revil-ransomware/
author: Florian Roth (Nextron Systems)
date: 2021-07-03
modified: 2022-05-20
tags:
    - attack.execution
    - attack.t1059
    - attack.g0115
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection1:
        CommandLine|contains:
            - 'C:\Windows\cert.exe'
            - 'del /q /f c:\kworking\agent.crt'
            - 'Kaseya VSA Agent Hot-fix'
            - '\AppData\Local\Temp\MsMpEng.exe'
            - 'rmdir /s /q %SystemDrive%\inetpub\logs'
            - 'del /s /q /f %SystemDrive%\\*.log'
            - 'c:\kworking1\agent.exe'
            - 'c:\kworking1\agent.crt'
    selection2:
        Image:
            - 'C:\Windows\MsMpEng.exe'
            - 'C:\Windows\cert.exe'
            - 'C:\kworking\agent.exe'
            - 'C:\kworking1\agent.exe'
    selection3:
        CommandLine|contains|all:
            - 'del /s /q /f'
            - 'WebPages\Errors\webErrorLog.txt'
    condition: 1 of selection*
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

1 of selection*

Stage 1: selection1

selection1:
    CommandLine|contains:
        - 'C:\Windows\cert.exe'
        - 'del /q /f c:\kworking\agent.crt'
        - 'Kaseya VSA Agent Hot-fix'
        - '\AppData\Local\Temp\MsMpEng.exe'
        - 'rmdir /s /q %SystemDrive%\inetpub\logs'
        - 'del /s /q /f %SystemDrive%\\*.log'
        - 'c:\kworking1\agent.exe'
        - 'c:\kworking1\agent.crt'

Stage 2: selection2

selection2:
    Image:
        - 'C:\Windows\MsMpEng.exe'
        - 'C:\Windows\cert.exe'
        - 'C:\kworking\agent.exe'
        - 'C:\kworking1\agent.exe'

Stage 3: selection3

selection3:
    CommandLine|contains|all:
        - 'del /s /q /f'
        - 'WebPages\Errors\webErrorLog.txt'

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
  • C:\Windows\cert.exe
  • Kaseya VSA Agent Hot-fix
  • WebPages\Errors\webErrorLog.txt
  • \AppData\Local\Temp\MsMpEng.exe
  • c:\kworking1\agent.crt
  • c:\kworking1\agent.exe
  • del /q /f c:\kworking\agent.crt
  • del /s /q /f
  • del /s /q /f %SystemDrive%\\*.log
  • rmdir /s /q %SystemDrive%\inetpub\logs
Imageeq
  • C:\Windows\MsMpEng.exe
  • C:\Windows\cert.exe
  • C:\kworking1\agent.exe
  • C:\kworking\agent.exe