GCP IAM Role Has Changed

Severity: informational
Group by: resource.labels.project_id
Compliance: CIS 2.6
Log types: GCP.AuditLog
Tags: GCP, Identity & Access Management, Privilege Escalation:Valid Accounts
Reference: https://cloud.google.com/iam/docs/creating-custom-roles
Source: github.com/panther-labs/panther-analysis

A custom role has been created, deleted, or updated.

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1078` Valid Accounts

Rule body yaml

AnalysisType: rule
Filename: gcp_iam_custom_role_changes.py
RuleID: "GCP.IAM.CustomRoleChanges"
DisplayName: "GCP IAM Role Has Changed"
Enabled: true
DedupPeriodMinutes: 1440 # 24 hours
LogTypes:
  - GCP.AuditLog
Tags:
  - GCP
  - Identity & Access Management
  - Privilege Escalation:Valid Accounts
Reports:
  CIS:
    - 2.6
  MITRE ATT&CK:
    - TA0004:T1078
Severity: Info
Description: A custom role has been created, deleted, or updated.
Runbook: No action needed, informational
Reference: https://cloud.google.com/iam/docs/creating-custom-roles
SummaryAttributes:
  - severity
  - p_any_ip_addresses
  - p_any_domain_names
Tests:
  - Name: Custom Role Created
    ExpectedResult: true
    Log:
      {
        "protoPayload":
          {
            "@type": "type.googleapis.com/google.cloud.audit.AuditLog",
            "status": {},
            "authenticationInfo":
              {
                "principalEmail": "user.name@runpanther.io",
                "principalSubject": "user:user.name@runpanther.io",
              },
            "requestMetadata":
              {
                "callerIp": "136.24.229.58",
                "callerSuppliedUserAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36,gzip(gfe)",
                "requestAttributes":
                  { "time": "2020-05-15T04:11:28.411897632Z", "auth": {} },
                "destinationAttributes": {},
              },
            "serviceName": "iam.googleapis.com",
            "methodName": "google.iam.admin.v1.CreateRole",
            "authorizationInfo":
              [
                {
                  "resource": "projects/western-verve-123456",
                  "permission": "iam.roles.create",
                  "granted": true,
                  "resourceAttributes": {},
                },
              ],
            "resourceName": "projects/western-verve-123456/roles/CustomRole",
            "serviceData":
              {
                "@type": "type.googleapis.com/google.iam.admin.v1.AuditData",
                "permissionDelta":
                  {
                    "addedPermissions":
                      [
                        "apigee.apiproducts.create",
                        "apigee.apiproducts.delete",
                        "apigee.apiproducts.get",
                      ],
                  },
              },
            "request":
              {
                "parent": "projects/western-verve-123456",
                "role":
                  {
                    "stage": 1,
                    "included_permissions":
                      [
                        "apigee.apiproducts.create",
                        "apigee.apiproducts.delete",
                        "apigee.apiproducts.get",
                      ],
                    "title": "Jack's custom role",
                    "description": "Created on: 2020-05-14",
                  },
                "@type": "type.googleapis.com/google.iam.admin.v1.CreateRoleRequest",
                "role_id": "CustomRole",
              },
            "response":
              {
                "name": "projects/western-verve-123456/roles/CustomRole",
                "group_title": "Custom",
                "title": "Jack's custom role",
                "included_permissions":
                  [
                    "apigee.apiproducts.create",
                    "apigee.apiproducts.delete",
                    "apigee.apiproducts.get",
                  ],
                "@type": "type.googleapis.com/google.iam.admin.v1.Role",
                "description": "Created on: 2020-05-14",
                "group_name": "custom",
                "etag": "BwWlqAHm9IY=",
                "stage": 1,
              },
          },
        "insertId": "y4nffme2rory",
        "resource":
          {
            "type": "iam_role",
            "labels":
              {
                "project_id": "western-verve-123456",
                "role_name": "projects/western-verve-123456/roles/CustomRole",
              },
          },
        "timestamp": "2020-05-15T04:11:28.224558457Z",
        "severity": "NOTICE",
        "logName": "projects/western-verve-123456/logs/cloudaudit.googleapis.com%2Factivity",
        "receiveTimestamp": "2020-05-15T04:11:29.472913078Z",
      }

Detection logic

Condition

resource.type eq "iam_role"
protoPayload.methodName in ["google.iam.admin.v1.CreateRole", "google.iam.admin.v1.DeleteRole", "google.iam.admin.v1.UpdateRole"]

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.CreateRole` `google.iam.admin.v1.DeleteRole` `google.iam.admin.v1.UpdateRole`
`resource.type`	eq	`iam_role`

`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)