Detections/SecurityEvent/password_never_expires.yaml

id: 6c360107-f3ee-4b91-9f43-f4cfd90441cf
name: AD account with Don't Expire Password
description: |
  'Identifies whenever a user account has the setting "Password Never Expires" in the user account properties selected.
  This is indicated in Security event 4738 in the EventData item labeled UserAccountControl with an included value of %%2089.
  %%2089 resolves to "Don't Expire Password - Enabled".'
severity: Low
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Persistence
relevantTechniques:
  - T1098
query: |
 union isfuzzy=true
 (
  SecurityEvent
  | where EventID == 4738
  // 2089 value indicates the Don't Expire Password value has been set
  | where UserAccountControl has "%%2089"
  | extend Value_2089 = iff(UserAccountControl has "%%2089","'Don't Expire Password' - Enabled", "Not Changed")
  // 2050 indicates that the Password Not Required value is NOT set, this often shows up at the same time as a 2089 and is the recommended value.  This value may not be in the event.
  | extend Value_2050 = iff(UserAccountControl has "%%2050","'Password Not Required' - Disabled", "Not Changed")
  // If value %%2082 is present in the 4738 event, this indicates the account has been configured to logon WITHOUT a password. Generally you should only see this value when an account is created and only in Event 4720: Account Creation Event.
  | extend Value_2082 = iff(UserAccountControl has "%%2082","'Password Not Required' - Enabled", "Not Changed")
  | project StartTime = TimeGenerated, EventID, Activity, Computer, TargetAccount, TargetUserName, TargetDomainName, TargetSid, 
  AccountType, UserAccountControl, Value_2089, Value_2050, Value_2082, SubjectAccount, SubjectUserName, SubjectDomainName, SubjectUserSid
  ),
  (
  WindowsEvent
  | where EventID == 4738 and EventData has '2089'
  // 2089 value indicates the Don't Expire Password value has been set
  | extend UserAccountControl = tostring(EventData.UserAccountControl)
  | where UserAccountControl has "%%2089"
  | extend Value_2089 = iff(UserAccountControl has "%%2089","'Don't Expire Password' - Enabled", "Not Changed")
  // 2050 indicates that the Password Not Required value is NOT set, this often shows up at the same time as a 2089 and is the recommended value.  This value may not be in the event.
  | extend Value_2050 = iff(UserAccountControl has "%%2050","'Password Not Required' - Disabled", "Not Changed")
  // If value %%2082 is present in the 4738 event, this indicates the account has been configured to logon WITHOUT a password. Generally you should only see this value when an account is created and only in Event 4720: Account Creation Event.
  | extend Value_2082 = iff(UserAccountControl has "%%2082","'Password Not Required' - Enabled", "Not Changed")
  | extend Activity="4738 - A user account was changed."
  | extend TargetAccount = strcat(EventData.TargetDomainName,"\\", EventData.TargetUserName)
  | extend TargetSid = tostring(EventData.TargetSid)
  | extend SubjectAccount = strcat(EventData.SubjectDomainName,"\\", EventData.SubjectUserName)
  | extend SubjectUserSid = tostring(EventData.SubjectUserSid)
  | extend AccountType=case(SubjectAccount endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
  | project StartTime = TimeGenerated, EventID, Activity, Computer, TargetAccount, TargetUserName = tostring(EventData.TargetUserName), TargetDomainName = tostring(EventData.TargetDomainName), TargetSid, 
  AccountType, UserAccountControl, Value_2089, Value_2050, Value_2082, SubjectAccount, SubjectDomainName = tostring(EventData.SubjectDomainName), SubjectUserName = tostring(EventData.SubjectUserName), SubjectUserSid = tostring(EventData.SubjectUserSid)
  )
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | project-away DomainIndex
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: TargetAccount
      - identifier: Name
        columnName: TargetUserName
      - identifier: NTDomain
        columnName: TargetDomainName
  - entityType: Account
    fieldMappings:
      - identifier: Sid
        columnName: TargetSid
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: SubjectAccount
      - identifier: Name
        columnName: SubjectUserName
      - identifier: NTDomain
        columnName: SubjectDomainName
  - entityType: Account
    fieldMappings:
      - identifier: Sid
        columnName: SubjectUserSid
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
version: 1.2.2
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]