GCP Workforce Pool Created or Updated

Severity: high
Log types: GCP.AuditLog
Tags: Account Manipulation, Additional Cloud Roles, GCP, Privilege Escalation
Reference: https://medium.com/google-cloud/detection-of-inbound-sso-persistence-techniques-in-gcp-c56f7b2a588b
Source: github.com/panther-labs/panther-analysis

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1098.003` Account Manipulation: Additional Cloud Roles, `T1136.003` Create Account: Cloud Account
Privilege Escalation	`T1098.003` Account Manipulation: Additional Cloud Roles

Rule body yaml

AnalysisType: rule
Filename: gcp_workforce_pool_created_or_updated.py
RuleID: "GCP.Workforce.Pool.Created.or.Updated"
DisplayName: "GCP Workforce Pool Created or Updated"
Enabled: true
LogTypes:
  - GCP.AuditLog
Tags:
  - Account Manipulation
  - Additional Cloud Roles
  - GCP
  - Privilege Escalation
Reports:
  MITRE ATT&CK:
    - TA0003:T1136.003
    - TA0003:T1098.003
    - TA0004:T1098.003
Severity: High
DedupPeriodMinutes: 60
Threshold: 1
Runbook: >
  Ensure that the Workforce Pool creation or modification was expected. Adversaries may use this to persist or allow additional access or escalate their privilege.
Reference: https://medium.com/google-cloud/detection-of-inbound-sso-persistence-techniques-in-gcp-c56f7b2a588b
Tests:
  - Name: DeleteWorkforcePool-False
    ExpectedResult: false
    Log:
      insertId: 1plwiv7e2lay7
      logName: organizations/123456789012/logs/cloudaudit.googleapis.com%2Factivity
      operation:
        first: true
        id: locations/global/workforcePools/test-pool/operations/bigar3hp32vamefaukfkaaq000000000
        producer: iam.googleapis.com
      protoPayload:
        "@type": type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: user@example.com
        authorizationInfo:
          - granted: true
            permission: iam.workforcePools.delete
            resource: locations/global/workforcePools/test-pool
            resourceAttributes: {}
        methodName: google.iam.admin.v1.WorkforcePools.DeleteWorkforcePool
        request:
          "@type": type.googleapis.com/google.iam.admin.v1.DeleteWorkforcePoolRequest
          name: locations/global/workforcePools/test-pool
        requestMetadata:
          callerIp: 07da:0994:97fb:8db1:c68f:c109:fcdd:d594
          callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/119.0,gzip(gfe),gzip(gfe)
          destinationAttributes: {}
          requestAttributes:
            auth: {}
            reason: 8uSywAYQGg5Db2xpc2V1bSBGbG93cw
            time: "2023-11-17T18:58:52.165673889Z"
        resourceName: locations/global/workforcePools/test-pool
        serviceName: iam.googleapis.com
      receiveTimestamp: "2023-11-17T18:58:52.901258022Z"
      resource:
        labels:
          method: google.iam.admin.v1.WorkforcePools.DeleteWorkforcePool
          service: iam.googleapis.com
        type: audited_resource
      severity: NOTICE
      timestamp: "2023-11-17T18:58:52.158942930Z"
  - Name: UpdateWorkforcePool-True
    ExpectedResult: true
    Log:
      insertId: 1h09dxwe33hgu
      logName: organizations/123456789012/logs/cloudaudit.googleapis.com%2Factivity
      operation:
        first: true
        id: locations/global/workforcePools/test-pool/operations/bigarg7n32vamefy6ximiaq000000000
        producer: iam.googleapis.com
      protoPayload:
        "@type": type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: user@example.com
        authorizationInfo:
          - granted: true
            permission: iam.workforcePools.update
            resource: locations/global/workforcePools/test-pool
            resourceAttributes: {}
        methodName: google.iam.admin.v1.WorkforcePools.UpdateWorkforcePool
        request:
          "@type": type.googleapis.com/google.iam.admin.v1.UpdateWorkforcePoolRequest
          updateMask: description,sessionDuration,disabled,displayName
          workforcePool:
            description: Test pool to facilitate detection writing
            displayName: Test Pool
            name: locations/global/workforcePools/test-pool
            sessionDuration: 43200s
        requestMetadata:
          callerIp: 07da:0994:97fb:8db1:c68f:c109:fcdd:d594
          callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/119.0,gzip(gfe),gzip(gfe)
          destinationAttributes: {}
          requestAttributes:
            auth: {}
            reason: 8uSywAYQGg5Db2xpc2V1bSBGbG93cw
            time: "2023-11-17T18:53:15.208909504Z"
        resourceName: locations/global/workforcePools/test-pool
        serviceName: iam.googleapis.com
      receiveTimestamp: "2023-11-17T18:53:16.523653141Z"
      resource:
        labels:
          method: google.iam.admin.v1.WorkforcePools.UpdateWorkforcePool
          service: iam.googleapis.com
        type: audited_resource
      severity: NOTICE
      timestamp: "2023-11-17T18:53:15.200613481Z"
  - Name: CreateWorkforcePool-True
    ExpectedResult: true
    Log:
      insertId: 6432zre32u1v
      logName: organizations/123456789012/logs/cloudaudit.googleapis.com%2Factivity
      operation:
        first: true
        id: locations/global/workforcePools/test-pool/operations/bifqrwxk32vamegiyoqaoeab00000000
        producer: iam.googleapis.com
      protoPayload:
        "@type": type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: user@example.com
        authorizationInfo:
          - granted: true
            permission: iam.workforcePools.create
            resource: organizations/123456789012
            resourceAttributes: {}
        methodName: google.iam.admin.v1.WorkforcePools.CreateWorkforcePool
        request:
          "@type": type.googleapis.com/google.iam.admin.v1.CreateWorkforcePoolRequest
          location: locations/global
          workforcePool:
            description: Test pool
            displayName: Test Pool
            name: locations/global/workforcePools/test-pool
            parent: organizations/325169835352
            sessionDuration: 3600s
            state: ACTIVE
          workforcePoolId: test-pool
        requestMetadata:
          callerIp: 07da:0994:97fb:8db1:c68f:c109:fcdd:d594
          callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/119.0,gzip(gfe),gzip(gfe)
          destinationAttributes: {}
          requestAttributes:
            auth: {}
            reason: 8uSywAYQGg5Db2xpc2V1bSBGbG93cw
            time: "2023-11-17T18:47:53.284817626Z"
        resourceName: organizations/325169835352
        serviceName: iam.googleapis.com
      receiveTimestamp: "2023-11-17T18:47:54.138395349Z"
      resource:
        labels:
          method: google.iam.admin.v1.WorkforcePools.CreateWorkforcePool
          service: iam.googleapis.com
        type: audited_resource
      severity: NOTICE
      timestamp: "2023-11-17T18:47:53.276929945Z"

Detection logic

Condition

protoPayload.methodName in ["google.iam.admin.v1.WorkforcePools.CreateWorkforcePool", "google.iam.admin.v1.WorkforcePools.UpdateWorkforcePool"]

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.

Field	Kind	Values
`protoPayload.methodName`	in	`google.iam.admin.v1.WorkforcePools.CreateWorkforcePool` `google.iam.admin.v1.WorkforcePools.UpdateWorkforcePool`

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.

Field	Source
`principalEmail`	`protoPayload.authenticationInfo.principalEmail`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)