GKE Service Account Modified RBAC Objects

[metadata]
creation_date = "2026/07/10"
integration = ["gcp"]
maturity = "production"
updated_date = "2026/07/10"

[rule]
author = ["Elastic"]
description = """
Detects write operations performed by GKE service accounts against RBAC resources (Roles, ClusterRoles, RoleBindings,
ClusterRoleBindings). Service accounts typically do not manage RBAC directly; this activity may indicate token abuse or
unauthorized privilege escalation.
"""
false_positives = [
    """
    In-cluster controllers, operators, and CI jobs may legitimately reconcile RBAC manifests. Baseline known automation
    service accounts before tuning.
    """,
]
from = "now-6m"
index = ["logs-gcp.audit-*"]
language = "kuery"
license = "Elastic License v2"
name = "GKE Service Account Modified RBAC Objects"
note = """## Triage and analysis

### Investigating GKE Service Account Modified RBAC Objects

This rule detects service accounts performing allowed write actions on RBAC resources. Stolen or over-privileged service
account tokens can silently alter authorization to gain or retain elevated access.

### Possible investigation steps

- Review `client.user.email`, `event.action`, and `gcp.audit.resource_name`.
- Trace the acting service account to its owning workload and inspect recent image changes or exec activity.
- Correlate with change tickets or GitOps commits for the same RBAC object.

### False positive analysis

- Platform operators and GitOps controllers running in-cluster commonly create or patch RBAC objects.

### Response and remediation

- Revert unauthorized RBAC changes, rotate the service account credentials, and tighten RBAC for the workload.

"""
setup = "The GCP Fleet integration with GKE audit logs enabled is required to be compatible with this rule."
references = [
    "https://kubernetes.io/docs/reference/access-authn-authz/rbac/",
    "https://heilancoos.github.io/research/2025/12/16/kubernetes.html#overly-permissive-role-based-access-control",
]
risk_score = 47
rule_id = "c41e9854-3df3-465a-8234-4d625084ff86"
severity = "medium"
tags = [
    "Domain: Cloud",
    "Domain: Kubernetes",
    "Data Source: GCP",
    "Data Source: Google Cloud Platform",
    "Use Case: Threat Detection",
    "Tactic: Privilege Escalation",
    "Tactic: Persistence",
    "Resources: Investigation Guide",
]
timestamp_override = "event.ingested"
type = "query"

query = '''
data_stream.dataset:gcp.audit and service.name:"k8s.io" and event.outcome:success and
client.user.email:(system\:serviceaccount\:* and not (
  "system:serviceaccount:kube-system:clusterrole-aggregation-controller" or
  "system:serviceaccount:kube-system:generic-garbage-collector"
)) and event.action:(
  "io.k8s.authorization.rbac.v1.clusterrolebindings.create" or
  "io.k8s.authorization.rbac.v1.clusterrolebindings.delete" or
  "io.k8s.authorization.rbac.v1.clusterrolebindings.patch" or
  "io.k8s.authorization.rbac.v1.clusterrolebindings.update" or
  "io.k8s.authorization.rbac.v1.clusterroles.create" or
  "io.k8s.authorization.rbac.v1.clusterroles.delete" or
  "io.k8s.authorization.rbac.v1.clusterroles.patch" or
  "io.k8s.authorization.rbac.v1.clusterroles.update" or
  "io.k8s.authorization.rbac.v1.rolebindings.create" or
  "io.k8s.authorization.rbac.v1.rolebindings.delete" or
  "io.k8s.authorization.rbac.v1.rolebindings.patch" or
  "io.k8s.authorization.rbac.v1.rolebindings.update" or
  "io.k8s.authorization.rbac.v1.roles.create" or
  "io.k8s.authorization.rbac.v1.roles.delete" or
  "io.k8s.authorization.rbac.v1.roles.patch" or
  "io.k8s.authorization.rbac.v1.roles.update"
)
'''

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1098"
name = "Account Manipulation"
reference = "https://attack.mitre.org/techniques/T1098/"

[[rule.threat.technique.subtechnique]]
id = "T1098.006"
name = "Additional Container Cluster Roles"
reference = "https://attack.mitre.org/techniques/T1098/006/"

[rule.threat.tactic]
id = "TA0004"
name = "Privilege Escalation"
reference = "https://attack.mitre.org/tactics/TA0004/"

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1098"
name = "Account Manipulation"
reference = "https://attack.mitre.org/techniques/T1098/"

[[rule.threat.technique.subtechnique]]
id = "T1098.006"
name = "Additional Container Cluster Roles"
reference = "https://attack.mitre.org/techniques/T1098/006/"

[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"

[rule.investigation_fields]
field_names = [
    "@timestamp",
    "client.user.email",
    "source.ip",
    "user_agent.original",
    "event.action",
    "event.outcome",
    "gcp.audit.resource_name",
    "gcp.audit.request.kind",
    "data_stream.namespace",
]