title: DirLister Execution
id: b4dc61f5-6cce-468e-a608-b48b469feaa2
status: test
description: Detect the usage of "DirLister.exe" a utility for quickly listing folder or drive contents. It was seen used by BlackCat ransomware to create a list of accessible directories and files.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/40b77d63808dd4f4eafb83949805636735a1fd15/atomics/T1083/T1083.md
    - https://news.sophos.com/en-us/2022/07/14/blackcat-ransomware-attacks-not-merely-a-byproduct-of-bad-luck/
author: frack113
date: 2022-08-20
modified: 2023-02-04
tags:
    - attack.discovery
    - attack.t1083
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        - OriginalFileName: 'DirLister.exe'
        - Image|endswith: '\DirLister.exe'
    condition: selection
falsepositives:
    - Legitimate use by users
level: low
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_dirlister_execution/info.yml
simulation:
    - type: atomic-red-team
      name: Launch DirLister Executable
      technique: T1083
      atomic_guid: c5bec457-43c9-4a18-9a24-fe151d8971b7

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