Detection rules › Kusto

Multiple Password Reset by user

Severity
low
Time window
1d
Group by
Account, Type
Author
Microsoft Security Research
Source
github.com/Azure/Azure-Sentinel

This query will determine multiple password resets by user across multiple data sources. Account manipulation including password reset may aid adversaries in maintaining access to credentials and certain permission levels within an environment.

MITRE ATT&CK coverage

TacticTechniques
Initial Access
Credential Access

Telemetry coverage

Rule body

id:  0b9ae89d-8cad-461c-808f-0494f70ad5c4
name: Multiple Password Reset by user
description: |
  'This query will determine multiple password resets by user across multiple data sources.
  Account manipulation including password reset may aid adversaries in maintaining access to credentials and certain permission levels within an environment.'
severity: Low
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
     - AuditLogs
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: Syslog
    dataTypes:
      - Syslog
  - connectorId: Office365
    dataTypes:
      - OfficeActivity
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvents
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - CredentialAccess
relevantTechniques:
  - T1078
  - T1110
query: |
  let selfServicePasswordReset = dynamic(["Self-service password reset flow activity progress", "Change password (self-service)", "Reset password (self-service)"]); 
  //Self-service password reset flow activity progress is typically caused by a password policy which requires users to rotate passwords. This operation already implies the user has signed in successfully and therefore the password reset is non-malicious.
  let PerUserThreshold = 5;
  let TotalThreshold = 100;
  let action = dynamic(["change", "changed", "reset"]);
  let pWord = dynamic(["password", "credentials"]);
  let PasswordResetMultiDataSource =
  (union isfuzzy=true
  (//Password reset events
  //4723: An attempt was made to change an account's password
  //4724: An attempt was made to reset an accounts password
  SecurityEvent
  | where EventID in ("4723","4724")
  | project TimeGenerated, Computer, AccountType, Account, Type, TargetUserName),
  (//Password reset events
  //4723: An attempt was made to change an account's password
  //4724: An attempt was made to reset an accounts password
  WindowsEvent
  | where EventID in ("4723","4724")
  | extend SubjectUserSid = tostring(EventData.SubjectUserSid)
  | extend TargetUserName = tostring(EventData.TargetUserName)
  | extend Account = strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend AccountType=case(Account endswith "$" or SubjectUserSid in ("S-1-5-18", "S-1-5-19", "S-1-5-20"), "Machine", isempty(SubjectUserSid), "", "User")
  | project TimeGenerated, Computer, AccountType, Account, Type, TargetUserName),
  (//Azure Active Directory Password reset events
  AuditLogs
  | where OperationName has_any (pWord) and OperationName has_any (action) and Result =~ "success"
  | where OperationName !in (selfServicePasswordReset)
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "User"
        | extend AccountType = tostring(TargetResource.type),
                 Account = tostring(InitiatedBy.user.userPrincipalName),
                 TargetUserName = tolower(tostring(TargetResource.userPrincipalName))
    )
  | project TimeGenerated, AccountType, Account, TargetUserName, Computer = "", Type),
  (//OfficeActive ActiveDirectory Password reset events
  OfficeActivity
  | where OfficeWorkload == "AzureActiveDirectory"
  | where (ExtendedProperties has_any (pWord) or ModifiedProperties has_any (pWord)) and (ExtendedProperties has_any (action) or ModifiedProperties has_any (action))
  | extend AccountType = UserType, Account = OfficeObjectId
  | project TimeGenerated, AccountType, Account, Type, Computer = ""),
  (// Unix syslog password reset events
  Syslog
  | where Facility in ("auth","authpriv")
  | where SyslogMessage has_any (pWord) and SyslogMessage has_any (action)
  | extend AccountType = iif(SyslogMessage contains "root", "Root", "Non-Root")
  | where SyslogMessage matches regex ".*password changed for.*"
  | parse SyslogMessage with * "password changed for" Account
  | project TimeGenerated, AccountType, Account, Computer = HostName, Type)
  );
  let pwrmd = PasswordResetMultiDataSource
  | project TimeGenerated, Computer, AccountType, Account, Type, TargetUserName;
  (union isfuzzy=true
  (pwrmd
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), Computerlist = make_set(Computer, 25), AccountType = make_set(AccountType, 25), Computer = arg_max(Computer , TimeGenerated), TargetUserList = make_set(TargetUserName, 25), TargetUserName = arg_max(TargetUserName, TimeGenerated), Total=count() by Account, Type
  | where Total > PerUserThreshold
  | extend ResetPivot = "PerUserReset"),
  (pwrmd
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), ComputerList = make_set(Computer, 25), AccountList = make_set(Account, 25), AccountType = make_set(AccountType, 25), Computer = arg_max(Computer , TimeGenerated), TargetUserList = make_set(TargetUserName, 25), TargetUserName = arg_max(TargetUserName, TimeGenerated), Total=count() by Type
  | where Total > TotalThreshold
  | extend ResetPivot = "TotalUserReset")
  )
  | extend timestamp = StartTimeUtc, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.')), Name = tostring(split(Account, '@', 0)[0]), UPNSuffix = tostring(split(Account, '@', 1)[0]), TargetName = tostring(split(TargetUserName,'@',0)[0]), TargetUPNSuffix = tostring(split(TargetUserName,'@',1)[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Account
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: TargetUserName
      - identifier: Name
        columnName: TargetName
      - identifier: UPNSuffix
        columnName: TargetUPNSuffix
version: 2.1.7
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others", "Identity" ]

Stages and Predicates

Parameters

let selfServicePasswordReset = dynamic(["Self-service password reset flow activity progress", "Change password (self-service)", "Reset password (self-service)"]);
let PerUserThreshold = 5;
let TotalThreshold = 100;
let action = dynamic(["change", "changed", "reset"]);
let pWord = dynamic(["password", "credentials"]);

union isfuzzy=true (2 sources)

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

Leg 1: pwrmd

pwrmd
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), Computerlist = make_set(Computer, 25), AccountType = make_set(AccountType, 25), Computer = arg_max(Computer , TimeGenerated), TargetUserList = make_set(TargetUserName, 25), TargetUserName = arg_max(TargetUserName, TimeGenerated), Total=count() by Account, Type
| where Total > PerUserThreshold
| extend ResetPivot = "PerUserReset"

Leg 2: pwrmd

pwrmd
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), ComputerList = make_set(Computer, 25), AccountList = make_set(Account, 25), AccountType = make_set(AccountType, 25), Computer = arg_max(Computer , TimeGenerated), TargetUserList = make_set(TargetUserName, 25), TargetUserName = arg_max(TargetUserName, TimeGenerated), Total=count() by Type
| where Total > TotalThreshold
| extend ResetPivot = "TotalUserReset"

Applied to the combined result

| extend timestamp = StartTimeUtc, HostName = tostring(split(Computer, '.', 0)[0]), DnsDomain = tostring(strcat_array(array_slice(split(Computer, '.'), 1, -1), '.')), Name = tostring(split(Account, '@', 0)[0]), UPNSuffix = tostring(split(Account, '@', 1)[0]), TargetName = tostring(split(TargetUserName,'@',0)[0]), TargetUPNSuffix = tostring(split(TargetUserName,'@',1)[0])

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
OperationNameinChange password (self-service), Reset password (self-service), Self-service password reset flow activity progressexcludes:OperationName field:"OperationName" value:"Change password (self-service)" field:"OperationName" value:"Reset password (self-service)" field:"OperationName" value:"Self-service password reset flow activity progress"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventIDin
  • 4723 corpus 4 (splunk 3, kusto 1)
  • 4724 corpus 2 (splunk 2)
field:"EventID" kind:in
ExtendedPropertiesmatch
  • change transforms: term
  • changed transforms: term
  • credentials transforms: term
  • password transforms: term
  • reset transforms: term
field:"ExtendedProperties" kind:match
Facilityin
  • auth
  • authpriv
field:"Facility" kind:in
ModifiedPropertiesmatch
  • change transforms: term
  • changed transforms: term
  • credentials transforms: term
  • password transforms: term
  • reset transforms: term
field:"ModifiedProperties" kind:match
OfficeWorkloadeq
  • AzureActiveDirectory
field:"m365::Workload" kind:eq value:"AzureActiveDirectory"
OperationNamematch
  • change transforms: term
  • changed transforms: term
  • credentials transforms: term
  • password transforms: term
  • reset transforms: term
field:"OperationName" kind:match
Resulteq
  • success corpus 31 (kusto 31)
field:"Result" kind:eq value:"success"
SyslogMessagematch
  • change transforms: term
  • changed transforms: term
  • credentials transforms: term
  • password transforms: term
  • reset transforms: term
field:"SyslogMessage" kind:match
SyslogMessageregex_match
  • .*password changed for.*
field:"SyslogMessage" kind:regex_match value:".*password changed for.*"
Totalgt
  • 100
  • 5 corpus 2 (kusto 2)
field:"Total" kind:gt
typeeq
  • User corpus 16 (kusto 16)
field:"type" kind:eq value:"User"

Output fields

These fields are emitted when the rule matches.

FieldSource
AccountListsummarize
AccountTypesummarize
Computersummarize
ComputerListsummarize
EndTimeUtcsummarize
StartTimeUtcsummarize
TargetUserListsummarize
TargetUserNamesummarize
Totalsummarize
Typesummarize
ResetPivotextend
DnsDomainextend
HostNameextend
Nameextend
TargetNameextend
TargetUPNSuffixextend
UPNSuffixextend
timestampextend