Sigma Rule Library

Load Of RstrtMgr.DLL By A Suspicious Process

Detects the load of RstrtMgr DLL (Restart Manager) by a suspicious process. This library has been used during ransomware campaigns to kill processes that would prevent file encryption by locking them (e.g. Conti ransomware, Cactus ransomware). It has also recently been seen used by the BiBi wiper for Windows. It could also be used for anti-analysis purposes by shut downing specific processes.

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Detection logic

selection_img

- ImageLoaded|endswith: \RstrtMgr.dll
- OriginalFileName: RstrtMgr.dll

selection_folders_1

Image|contains:
  - :\Perflogs\
  - :\Users\Public\
  - \Temporary Internet

selection_folders_2

- Image|contains|all:
    - :\Users\
    - \Favorites\
- Image|contains|all:
    - :\Users\
    - \Favourites\
- Image|contains|all:
    - :\Users\
    - \Contacts\

Condition

selection_img and 1 of selection_folders_*

Raw YAML

title: Load Of RstrtMgr.DLL By A Suspicious Process
id: b48492dc-c5ef-4572-8dff-32bc241c15c8
related:
    - id: 3669afd2-9891-4534-a626-e5cf03810a61
      type: derived
status: test
description: |
    Detects the load of RstrtMgr DLL (Restart Manager) by a suspicious process.
    This library has been used during ransomware campaigns to kill processes that would prevent file encryption by locking them (e.g. Conti ransomware, Cactus ransomware). It has also recently been seen used by the BiBi wiper for Windows.
    It could also be used for anti-analysis purposes by shut downing specific processes.
references:
    - https://www.crowdstrike.com/blog/windows-restart-manager-part-1/
    - https://www.crowdstrike.com/blog/windows-restart-manager-part-2/
    - https://web.archive.org/web/20231221193106/https://www.swascan.com/cactus-ransomware-malware-analysis/
    - https://taiwan.postsen.com/business/88601/Hamas-hackers-use-data-destruction-software-BiBi-which-consumes-a-lot-of-processor-resources-to-wipe-Windows-computer-data--iThome.html
author: Luc Génaux
date: 2023-11-28
tags:
    - attack.impact
    - attack.defense-impairment
    - attack.t1486
    - attack.t1685
logsource:
    category: image_load
    product: windows
detection:
    selection_img:
        - ImageLoaded|endswith: '\RstrtMgr.dll'
        - OriginalFileName: 'RstrtMgr.dll'
    selection_folders_1:
        Image|contains:
            # Note: increase coverage by adding more suspicious paths
            - ':\Perflogs\'
            - ':\Users\Public\'
            - '\Temporary Internet'
    selection_folders_2:
        - Image|contains|all:
              - ':\Users\'
              - '\Favorites\'
        - Image|contains|all:
              - ':\Users\'
              - '\Favourites\'
        - Image|contains|all:
              - ':\Users\'
              - '\Contacts\'
    condition: selection_img and 1 of selection_folders_*
falsepositives:
    - Processes related to software installation
level: high

False positives

  • Processes related to software installation

References

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