Query: rule covering Detects changes to the "MaxMpxCt" registry value. MaxMpxCt specifies the maximum outstanding network requests for the se
Matching passage: Sigma rule: Detects changes to the "MaxMpxCt" registry value. MaxMpxCt specifies the maximum outstanding network requests for the se. Logsource: windows / registry_set. Rule: title: MaxMpxCt Registry Value Changed id: 0e6a9e62-627e-496c-aef5-bfa39da29b5e status: test description: 'Detects changes to the "MaxMpxCt" registry value. MaxMpxCt specifies the maximum outstanding network requests for the server per client, which is used when negotiating a Server Message Block (SMB) connection with a client. Note if the value is set beyond 125 older Windows 9x clients will fail to negotiate. Ransomware threat actors and operators (specifically BlackCat) were seen increasing this value in order to handle a higher volume of traffic. ' references: - https://www.huntress.com/blog/blackcat-ransomware-affiliate-ttps - https://securityscorecard.com/research/deep-dive-into-alphv-blackcat-ransomware - https://www.intrinsec.com/alphv-ransomware-gang-analysis/?cn-reloaded=1 - https://www.sentinelone.com/labs/blackcat-ransomware-highly-configurable-rust-driven-raas-on-the-prowl-for-victims/ author: Nasreddine Bencherchali (Nextron Systems) date: 2024-03-19 tags: - attack.stealth - attack.t1070.005 logsource: category: registry_set product: windows detection: selection: TargetObject|endswith: \Services\LanmanServer\Parameters\MaxMpxCt condition: selection falsepositives: - Unknown level: low
Near-miss passage: Sigma rule: Detects execution of the "mofcomp" utility as a child of a suspicious shell or script running utility or by having a sus. Logsource: windows / process_creation. Rule: title: Potential Suspicious Mofcomp Execution id: 1dd05363-104e-4b4a-b963-196a534b03a1 status: test description: 'Detects execution of the "mofcomp" utility as a child of a suspicious shell or script running utility or by having a suspicious path in the commandline. The "mofcomp" utility parses a file containing MOF statements and adds the classes and class instances defined in the file to the WMI repository. Attackers abuse this utility to install malicious MOF scripts ' references: - https://thedfirreport.com/2022/07/11/select-xmrig-from-sqlserver/ - https://github.com/The-DFIR-Report/Sigma-Rules/blob/75260568a7ffe61b2458ca05f6f25914efb44337/win_mofcomp_execution.yml - https://learn.microsoft.com/en-us/windows/win32/wmisdk/mofcomp author: Nasreddine Bencherchali (Nextron Systems) date: 2022-07-12 modified: 2023-04-11 tags: - attack.stealth - attack.t1218 logsource: category: process_creation product: windows detection: selection_img: - Image|endswith: \mofcomp.exe - OriginalFileName: mofcomp.exe selection_case: - ParentImage|endswith: - \cmd.exe - \powershell.exe - \pwsh.exe - \wsl.exe - \wscript.exe - \cscript.exe - CommandLine|contains: - \AppData\Local\Temp - \Users\Public\ - \WINDOWS\Temp\ - '%temp%' - '%tmp%' - '%appdata%' filter_main_wmiprvse: ParentImage: C:\Windows\System32\wbem\WmiPrvSE.exe CommandLine|contains: C:\Windows\TEMP\ CommandLine|endswith: .mof filter_optional_null_parent: CommandLine|contains: C:\Windows\TEMP\ CommandLine|endswith: .mof condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Unknown level: high