GCP User Added to IAP Protected Service

Severity: low
Entities: emails, ip_addresses
Log types: GCP.AuditLog
Reference: https://cloud.google.com/iap/docs/managing-access
Source: github.com/panther-labs/panther-analysis

A user has been granted access to a IAP protected service.

Rule body yaml

AnalysisType: rule
Description: A user has been granted access to a IAP protected service.
DisplayName: "GCP User Added to IAP Protected Service"
Enabled: true
Filename: gcp_user_added_to_iap_protected_service.py
Runbook: "Note: GCP logs all bindings everytime this event occurs, not just changes. Bindings should be reviewed to ensure no unintended users have been added. "
Reference: https://cloud.google.com/iap/docs/managing-access
Severity: Low
Tests:
  - ExpectedResult: false
    Log:
      insertid: abcdefghijklmn
      logname: projects/gcp-project1/logs/cloudaudit.googleapis.com%2Factivity
      operation:
        id: 1234567890123-gcp-project1:abcdefghijklmnopqrstuvwz
        last: true
        producer: bigquery.googleapis.com
      p_any_emails:
        - user@company.io
      p_any_ip_addresses:
        - 1.2.3.4
      p_event_time: "2023-03-28 18:37:06.079"
      p_log_type: GCP.AuditLog
      p_parse_time: "2023-03-28 18:38:14.478"
      p_row_id: 06bf03d9d5dfbadba981899e1787bf05
      p_schema_version: 0
      p_source_id: 964c7894-9a0d-4ddf-864f-0193438221d6
      p_source_label: gcp-logsource
      protoPayload:
        at_sign_type: type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: user@company.io
        authorizationInfo:
          - granted: true
            permission: bigquery.tables.delete
            resource: projects/gcp-project1/datasets/test1/tables/newtable
        metadata:
          "@type": type.googleapis.com/google.cloud.audit.BigQueryAuditMetadata
          methodName: google.cloud.bigquery.v2.JobService.InsertJob
          requestMetadata:
            callerIP: 1.2.3.4
            callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36,gzip(gfe),gzip(gfe)
          resourceName: projects/gcp-project1/datasets/test1/tables/newtable
          serviceName: bigquery.googleapis.com
          status: {}
          tableDeletion:
            jobName: projects/gcp-project1/jobs/bquxjob_5e4a0679_18729a639d7
            reason: QUERY
        receivetimestamp: "2023-03-28 18:37:06.745"
        resource:
          labels:
            dataset_id: test1
            project_id: gcp-project1
          type: bigquery_dataset
        severity: NOTICE
        timestamp: "2023-03-28 18:37:06.079"
    Name: other
  - ExpectedResult: true
    Log:
      insertId: 46ee5sd38mw
      logName: projects/gcp-project1/logs/cloudaudit.googleapis.com%2Factivity
      p_any_emails:
        - staging@company.io
      p_any_ip_addresses:
        - 1.2.3.4
      p_event_time: "2023-04-25 19:20:57.024"
      p_log_type: GCP.AuditLog
      p_parse_time: "2023-04-25 19:22:14.743"
      p_row_id: b2e9b7f5dc85a69981fac2e417b6bb03
      p_schema_version: 0
      p_source_id: 5b77391b-afad-46c7-8ddc-b8e21d4726b3
      p_source_label: gcplogsource2
      protoPayload:
        at_sign_type: type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: staging@company.io
        authorizationInfo:
          - granted: true
            permission: iap.webServices.setIamPolicy
            resourceAttributes:
              name: projects/123456789012/iap_web/compute/services/7312383563505470445
              service: iap.googleapis.com
              type: iap.googleapis.com/WebService
        methodName: google.cloud.iap.v1.IdentityAwareProxyAdminService.SetIamPolicy
        request:
          "@type": type.googleapis.com/google.iam.v1.SetIamPolicyRequest
          policy:
            etag: BwX6LgT4YMw=
          resource: projects/123456789012/iap_web/compute/services/7312383563505470445
        requestMetadata:
          callerIP: 1.2.3.4
          callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36,gzip(gfe),gzip(gfe)
          destinationAttributes: {}
          requestAttributes:
            auth: {}
            time: "2023-04-25T19:20:57.295723118Z"
        resourceName: projects/123456789012/iap_web/compute/services/7312383563505470445
        response:
          "@type": type.googleapis.com/google.iam.v1.Policy
          etag: BwX6LgXbpsw=
        serviceName: iap.googleapis.com
      receiveTimestamp: "2023-04-25 19:20:58.16"
      resource:
        labels:
          backend_service_id: ""
          location: ""
          project_id: gcp-project1
        type: gce_backend_service
      severity: NOTICE
      timestamp: "2023-04-25 19:20:57.024"
    Name: Other IAP Event
  - ExpectedResult: true
    Log:
      insertId: yyultvcrhy
      logName: projects/gcp-projet1/logs/cloudaudit.googleapis.com%2Factivity
      p_any_emails:
        - staging@company.io
      p_any_ip_addresses:
        - 1.2.3.4
      p_event_time: "2023-04-25 19:20:42.138"
      p_log_type: GCP.AuditLog
      p_parse_time: "2023-04-25 19:22:14.743"
      p_row_id: b2e9b7f5dc85a69981fac2e417b7bb03
      p_schema_version: 0
      p_source_id: 5b77391b-afad-46c7-8ddc-b8e21d4726b3
      p_source_label: gcplogsource2
      protoPayload:
        at_sign_type: type.googleapis.com/google.cloud.audit.AuditLog
        authenticationInfo:
          principalEmail: staging@company.io
        authorizationInfo:
          - granted: true
            permission: iap.webServices.setIamPolicy
            resourceAttributes:
              name: projects/123456789012/iap_web/compute/services/7312383563505470445
              service: iap.googleapis.com
              type: iap.googleapis.com/WebService
        methodName: google.cloud.iap.v1.IdentityAwareProxyAdminService.SetIamPolicy
        request:
          "@type": type.googleapis.com/google.iam.v1.SetIamPolicyRequest
          policy:
            bindings:
              - members:
                  - serviceAccount:test-account3@gcp-project1.iam.gserviceaccount.com
                role: roles/viewer
            etag: ACAB
          resource: projects/123456789012/iap_web/compute/services/7312383563505470445
        requestMetadata:
          callerIP: 1.2.3.4
          callerSuppliedUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36,gzip(gfe),gzip(gfe)
          destinationAttributes: {}
          requestAttributes:
            auth: {}
            time: "2023-04-25T19:20:42.399215146Z"
        resourceName: projects/123456789012/iap_web/compute/services/7312383563505470445
        response:
          "@type": type.googleapis.com/google.iam.v1.Policy
          bindings:
            - members:
                - serviceAccount:test-account3@gcp-project1.iam.gserviceaccount.com
              role: roles/viewer
          etag: BwX6LgT4YMw=
        serviceName: iap.googleapis.com
      receiveTimestamp: "2023-04-25 19:20:43.033"
      resource:
        labels:
          backend_service_id: ""
          location: ""
          project_id: gcp-project1
        type: gce_backend_service
      severity: NOTICE
      timestamp: "2023-04-25 19:20:42.138"
    Name: Add User to IAP
DedupPeriodMinutes: 60
LogTypes:
  - GCP.AuditLog
RuleID: "GCP.User.Added.to.IAP.Protected.Service"
Threshold: 1

Detection logic

Condition

protoPayload.methodName eq "google.cloud.iap.v1.IdentityAwareProxyAdminService.SetIamPolicy"

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`	eq	`google.cloud.iap.v1.IdentityAwareProxyAdminService.SetIamPolicy`

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
`bindings`	`protoPayload.request.policy.bindings`
`principalEmail`	`protoPayload.authenticationInfo.principalEmail`
`resource`	`protoPayload.request.resource`

`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)