Suspicious Registry Modification of MaxMpxCt Parameters

 1title: Suspicious Registry Modification of MaxMpxCt Parameters
 2id: 9fc5784b-50ab-4f0e-8044-5e15990d48a1
 3status: experimental
 4description: Detects registry modifications to change MaxMpxCt settings. BlackCat does this to increase the number of outstanding requests allowed, such as SMB requests to distribute ransomware through an environment.
 5references:
 6    - https://www.microsoft.com/en-us/security/blog/2022/06/13/the-many-lives-of-blackcat-ransomware/
 7author: Micah Babinski
 8date: 2022/12/04
 9tags:
10    - attack.command_and_control
11    - attack.defense_evasion
12    - attack.t1105
13    - attack.t1562
14logsource:
15    category: process_creation
16    product: windows
17detection:
18    selection:
19        CommandLine|contains|all:
20            - 'LanmanServer'
21            - 'parameters'
22            - 'MaxMpxCt'
23            - '65535'
24    condition: selection
25falsepositives:
26    - Unknown
27level: high```