title: Multiple Failed Logins with Different Accounts from Single Source System
description: Detects suspicious failed logins with different user accounts from a single source system 
author: Florian Roth
logsource:
    product: windows
    service: security
detection:
    selection1:
        EventID:
            - 529
            - 4625
        UserName: not null
        WorkstationName: not null
    selection2:
        EventID: 4776
        UserName: not null
        Workstation: not null
    timeframe: 24h 
    condition:
        - selection1 | count(UserName) by WorkstationName > 3
        - selection2 | count(UserName) by Workstation > 3
falsepositives:
    - Terminal servers
    - Jump servers
    - Other multiuser systems like Citrix server farms
    - Workstations with frequently changing users 
level: medium