Bucket Hijacking Exploit Redirects Cloud Audit Logs Undetected
Researchers have identified a novel cloud storage vulnerability known as bucket hijacking, where malicious actors exploit cloud infrastructure to covertly redirect critical security data into compromised environments.
Bucket Hijacking Attack Overview
Researchers have identified a novel cloud storage vulnerability known as bucket hijacking, where malicious actors exploit cloud infrastructure to covertly redirect critical security data into compromised environments. This method enables attackers to intercept audit logs and telemetry streams without triggering system alerts. Security experts at Palo Alto Networks’ Unit 42 have validated this technique, which affects cloud platforms including Google Cloud, AWS, and Microsoft Azure. The flaw has been reported to all three providers through responsible disclosure processes. While no confirmed instances of this attack in the wild have been documented, the potential for undetected data exfiltration remains a significant risk.
The attack leverages the global uniqueness of cloud storage bucket names. An adversary with deletion privileges can execute the following steps: first, remove the target organization’s active storage bucket. Second, immediately recreate a bucket with the same name under their own account. Third, allow existing data pipelines—such as Google Cloud logging sinks, AWS S3 replication rules, or Azure Monitor diagnostic exports—to continue functioning normally, directing sensitive information into the attacker’s controlled bucket. This process operates autonomously once initiated. The original configuration appears valid during inspections, generates no errors, and bypasses native monitoring mechanisms. Audit logs, system metrics, and security telemetry flow uninterrupted into the malicious environment, remaining undetected for extended periods.
Security experts at Palo Alto Networks’ Unit 42 have validated this technique, which affects cloud platforms including Google Cloud, AWS, and Microsoft Azure.
Validation Across Major Cloud Providers
Google Cloud
The attack was confirmed against Cloud Logging sinks, Pub/Sub subscriptions with Cloud Storage destinations, and Storage Transfer Service jobs. The required permissions included storage.buckets.delete and storage.objects.delete, which are typically granted by default to administrative roles.
AWS
The technique was validated using S3 bucket replication and Amazon Data Firehose pipelines targeting S3 destinations.
Azure
Azure’s implementation allowed a cross-subscription attack via Azure Monitor diagnostic settings, though name reuse restrictions currently limit its scope to the same tenant.
A critical vulnerability in Google Cloud’s permission model was highlighted. The standard Storage Admin role permits storage.buckets.delete operations without requiring the more restrictive logging.sinks.update permission needed to modify data streams. This gap enables attackers to redirect logs without altering configuration settings.
Implications for Organizational Security
Audit logs serve as the primary defense mechanism for detecting unauthorized access and breaches. By rerouting these logs, attackers can erase evidence of their activities before an intrusion is discovered. Security teams reviewing the logging console would see no anomalies, as the hijacked data stream appears normal. For regulated sectors such as finance, healthcare, and critical infrastructure, the consequences extend beyond data loss. Compromised audit logs could invalidate compliance certifications, hinder forensic investigations, and lead to legal liabilities.
Mitigation Strategies
Unit 42 advises organizations to implement two key defenses. First, restrict deletion permissions to only essential administrative roles. On Google Cloud, this includes limiting storage.buckets.delete; on AWS, DeleteBucket; and on Azure, Microsoft.Storage/storageAccounts/delete. These permissions should not be assigned broadly by default. Second, enforce data perimeter controls. AWS Service Control Policies and Google Cloud VPC Service Controls can prevent data from being written to untrusted buckets. Activating these measures ensures that even if a bucket is hijacked, the original data stream cannot redirect to external locations. Proactive monitoring for unusual bucket deletion events and rapid re-creation of identical names should be integrated into cloud security protocols. Organizations must act swiftly to address this emerging threat vector.
Unit 42 advises organizations to implement two key defenses.
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