Load Of RstrtMgr.DLL By An Uncommon Process

Detects the load of RstrtMgr DLL (Restart Manager) by an uncommon 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.

Sigma rule (View on GitHub)

 1title: Load Of RstrtMgr.DLL By An Uncommon Process
 2id: 3669afd2-9891-4534-a626-e5cf03810a61
 3related:
 4    - id: b48492dc-c5ef-4572-8dff-32bc241c15c8
 5      type: derived
 6status: test
 7description: |
 8    Detects the load of RstrtMgr DLL (Restart Manager) by an uncommon process.
 9    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.
10    It could also be used for anti-analysis purposes by shut downing specific processes.    
11references:
12    - https://www.crowdstrike.com/blog/windows-restart-manager-part-1/
13    - https://www.crowdstrike.com/blog/windows-restart-manager-part-2/
14    - https://web.archive.org/web/20231221193106/https://www.swascan.com/cactus-ransomware-malware-analysis/
15    - 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
16author: Luc Génaux
17date: 2023-11-28
18tags:
19    - attack.impact
20    - attack.defense-evasion
21    - attack.t1486
22    - attack.t1562.001
23logsource:
24    category: image_load
25    product: windows
26detection:
27    selection:
28        - ImageLoaded|endswith: '\RstrtMgr.dll'
29        - OriginalFileName: 'RstrtMgr.dll'
30    filter_main_generic:
31        Image|contains:
32            - ':\$WINDOWS.~BT\'
33            - ':\$WinREAgent\'
34            - ':\Program Files (x86)\'
35            - ':\Program Files\'
36            - ':\ProgramData\'
37            - ':\Windows\explorer.exe'
38            - ':\Windows\SoftwareDistribution\'
39            - ':\Windows\SysNative\'
40            - ':\Windows\System32\'
41            - ':\Windows\SysWOW64\'
42            - ':\Windows\WinSxS\'
43            - ':\WUDownloadCache\'
44    filter_main_user_software_installations:
45        Image|contains|all:
46            - ':\Users\'
47            - '\AppData\Local\Temp\is-'
48            - '.tmp\'
49        Image|endswith: '.tmp'
50    filter_main_admin_software_installations:
51        Image|contains: ':\Windows\Temp\'
52    condition: selection and not 1 of filter_main_*
53falsepositives:
54    - Other legitimate Windows processes not currently listed
55    - Processes related to software installation
56level: low

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