Detection rules › Kusto

AD account with Don't Expire Password

Severity
low
Time window
1d
Author
Microsoft Security Research
Source
github.com/Azure/Azure-Sentinel

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".

MITRE ATT&CK coverage

TacticTechniques
Persistence

Telemetry coverage

Rule body

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" ]

Stages and Predicates

union isfuzzy=true (2 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: SecurityEvent, WindowsEvent

Leg 1: SecurityEvent

SecurityEvent
 | where EventID == 4738
 | where UserAccountControl has "%%2089"
 | extend Value_2089 = iff(UserAccountControl has "%%2089","'Don't Expire Password' - Enabled", "Not Changed")
 | extend Value_2050 = iff(UserAccountControl has "%%2050","'Password Not Required' - Disabled", "Not Changed")
 | 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

Leg 2: WindowsEvent

WindowsEvent
 | where EventID == 4738 and EventData has '2089'
 | extend UserAccountControl = tostring(EventData.UserAccountControl)
 | where UserAccountControl has "%%2089"
 | extend Value_2089 = iff(UserAccountControl has "%%2089","'Don't Expire Password' - Enabled", "Not Changed")
 | extend Value_2050 = iff(UserAccountControl has "%%2050","'Password Not Required' - Disabled", "Not Changed")
 | 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)

Applied to the combined result

| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
 | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
 | project-away DomainIndex

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventDatamatch
  • 2089 transforms: term
field:"EventData" kind:match value:"2089"
EventIDeq
  • 4738 corpus 8 (splunk 4, elastic 3, kusto 1)
field:"EventID" kind:eq value:"4738"
UserAccountControlmatch
  • %%2089 transforms: term
field:"UserAccountControl" kind:match value:"%%2089"

Output fields

These fields are emitted when the rule matches.

FieldSource
AccountTypeproject
Activityproject
Computerproject
EventIDproject
StartTimeproject
SubjectAccountproject
SubjectDomainNameproject
SubjectUserNameproject
SubjectUserSidproject
TargetAccountproject
TargetDomainNameproject
TargetSidproject
TargetUserNameproject
UserAccountControlproject
Value_2050project
Value_2082project
Value_2089project
HostNameextend
HostNameDomainextend