diff --git a/rules/gcp/defense_evasion_gcp_storage_bucket_permissions_modified.toml b/rules/gcp/defense_evasion_gcp_storage_bucket_permissions_modified.toml
new file mode 100644
index 000000000..5bf991eab
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+++ b/rules/gcp/defense_evasion_gcp_storage_bucket_permissions_modified.toml
@@ -0,0 +1,48 @@
+[metadata]
+creation_date = "2020/09/21"
+ecs_version = ["1.6.0"]
+maturity = "production"
+updated_date = "2020/09/21"
+
+[rule]
+author = ["Elastic"]
+description = """
+Identifies when the Identity and Access Management (IAM) permissions are modified for a Google Cloud Platform (GCP)
+storage bucket. An adversary may modify the permissions on a storage bucket to weaken their target's security controls
+or an administrator may inadvertently modify the permissions, which could lead to data exposure or loss.
+"""
+false_positives = [
+    """
+    Storage bucket permissions may be modified by system administrators. Verify that the configuration change was
+    expected. Exceptions can be added to this rule to filter expected behavior.
+    """,
+]
+index = ["filebeat-*"]
+language = "kuery"
+license = "Elastic License"
+name = "GCP Storage Bucket Permissions Modification"
+note = "The GCP Filebeat module must be enabled to use this rule."
+references = ["https://cloud.google.com/storage/docs/access-control/iam-permissions"]
+risk_score = 47
+rule_id = "2326d1b2-9acf-4dee-bd21-867ea7378b4d"
+severity = "medium"
+tags = ["Elastic", "GCP", "Continuous Monitoring", "SecOps", "Identity and Access"]
+type = "query"
+
+query = '''
+event.module:googlecloud and event.dataset:googlecloud.audit and event.action:storage.setIamPermissions and event.outcome:success
+'''
+
+
+[[rule.threat]]
+framework = "MITRE ATT&CK"
+[[rule.threat.technique]]
+id = "T1222"
+name = "File and Directory Permissions Modification"
+reference = "https://attack.mitre.org/techniques/T1222/"
+
+
+[rule.threat.tactic]
+id = "TA0005"
+name = "Defense Evasion"
+reference = "https://attack.mitre.org/tactics/TA0005/"