Detection rules › Kusto

Azure DevOps Personal Access Token (PAT) misuse

Status
available
Severity
high
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'This Alert detects whenever a PAT is used in ways that PATs are not normally used. May require an allow list and baselining. Reference - https://docs.microsoft.com/azure/devops/organizations/accounts/use-personal-access-tokens-to-authenticate?view=azure-devops&tabs=preview-page Use this query for baselining: ADOAuditLogs | distinct OperationName'

MITRE ATT&CK coverage

Rule body kusto

id: ac891683-53c3-4f86-86b4-c361708e2b2b
name: Azure DevOps Personal Access Token (PAT) misuse
description: |
  'This Alert detects whenever a PAT is used in ways that PATs are not normally used. May require an allow list and baselining.
  Reference - https://docs.microsoft.com/azure/devops/organizations/accounts/use-personal-access-tokens-to-authenticate?view=azure-devops&tabs=preview-page
  Use this query for baselining:
  ADOAuditLogs
  | distinct OperationName'
severity: High
status: Available
requiredDataConnectors: []
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Execution
  - Impact
relevantTechniques:
  - T1496
  - T1559
query: |
  // Allowlisted UPNs should likely stay empty
  let AllowlistedUpns = datatable(UPN:string)['foo@bar.com', 'test@foo.com'];
  // Operation Name parts that will alert
  let HasAnyBlocklist = datatable(OperationNamePart:string)['Security.','Project.','AuditLog.','Extension.'];
  // Distinct Operation Names that will flag
  let HasExactBlocklist = datatable(OperationName:string)['Group.UpdateGroupMembership.Add','Library.ServiceConnectionExecuted','Pipelines.PipelineModified',
  'Release.ReleasePipelineModified', 'Git.RefUpdatePoliciesBypassed'];
  ADOAuditLogs
  | where AuthenticationMechanism startswith "PAT" and (OperationName has_any (HasAnyBlocklist) or OperationName in (HasExactBlocklist))
    and ActorUPN !in (AllowlistedUpns)
  | project TimeGenerated, AuthenticationMechanism, ProjectName, ActorUPN, ActorDisplayName, IpAddress, UserAgent, OperationName, Details, Data
  | extend timestamp = TimeGenerated
  | extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: ActorUPN
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IpAddress
version: 1.0.6
kind: Scheduled

Stages and Predicates

Let binding: AllowlistedUpns

let AllowlistedUpns = datatable(UPN:string)['foo@bar.com', 'test@foo.com'];

Let binding: HasAnyBlocklist

let HasAnyBlocklist = datatable(OperationNamePart:string)['Security.','Project.','AuditLog.','Extension.'];

Let binding: HasExactBlocklist

let HasExactBlocklist = datatable(OperationName:string)['Group.UpdateGroupMembership.Add','Library.ServiceConnectionExecuted','Pipelines.PipelineModified',
'Release.ReleasePipelineModified', 'Git.RefUpdatePoliciesBypassed'];

Stage 1: source

ADOAuditLogs

Stage 2: where

| where AuthenticationMechanism startswith "PAT" and (OperationName has_any (HasAnyBlocklist) or OperationName in (HasExactBlocklist))
  and ActorUPN !in (AllowlistedUpns)

References AllowlistedUpns, HasAnyBlocklist, HasExactBlocklist (defined above).

Stage 3: project

| project TimeGenerated, AuthenticationMechanism, ProjectName, ActorUPN, ActorDisplayName, IpAddress, UserAgent, OperationName, Details, Data

Stage 4: extend

| extend timestamp = TimeGenerated

Stage 5: extend

| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
ActorUPNeqAllowlistedUpns

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
AuthenticationMechanismstarts_with
  • PAT
OperationNamein
  • HasExactBlocklist transforms: cased
OperationNamematch
  • HasAnyBlocklist

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
ActorDisplayNameproject
ActorUPNproject
AuthenticationMechanismproject
Dataproject
Detailsproject
IpAddressproject
OperationNameproject
ProjectNameproject
TimeGeneratedproject
UserAgentproject
timestampextend
AccountNameextend
AccountUPNSuffixextend