CVE-2018-16846 in Ceph
Summary
by MITRE
It was found in Ceph versions before 13.2.4 that authenticated ceph RGW users can cause a denial of service against OMAPs holding bucket indices.
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Analysis
by VulDB Data Team • 07/01/2023
The vulnerability identified as CVE-2018-16846 affects Ceph storage systems, specifically impacting versions prior to 13.2.4 where authenticated Ceph Rados Gateway (RGW) users can trigger a denial of service condition against OMAPs that store bucket indices. This issue represents a significant operational risk for organizations relying on Ceph's object storage capabilities, as it allows authenticated attackers to disrupt the availability of critical storage metadata operations. The vulnerability stems from improper handling of OMAP operations within the Ceph RGW component, which serves as the gateway for RESTful access to Ceph's object storage system.
The technical flaw manifests when authenticated RGW users perform specific operations that cause the OMAP backend to become unresponsive or crash, leading to a denial of service condition for bucket index operations. OMAP (Object Map) is a key-value store used by Ceph to maintain metadata about buckets, including their properties and object mappings. When the OMAP system becomes compromised through this vulnerability, it affects the availability of bucket index data, which is fundamental to Ceph's ability to locate and retrieve objects within buckets. The flaw exploits the lack of proper validation and resource management during OMAP operations, allowing malicious users to consume excessive resources or trigger internal state corruption that results in system unresponsiveness.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects the core functionality of Ceph's object storage layer. Organizations using Ceph for large-scale data storage, cloud infrastructure, or distributed applications face potential outages that could affect thousands of applications or services dependent on the storage system. The vulnerability is particularly concerning because it requires only authenticated access, meaning that users with legitimate credentials can exploit this weakness, potentially leading to insider threats or compromised accounts. This makes the attack vector more accessible compared to vulnerabilities requiring privileged access or complex exploitation techniques.
Mitigation strategies for CVE-2018-16846 primarily focus on upgrading Ceph installations to version 13.2.4 or later, where the vulnerability has been addressed through improved OMAP handling and resource management. Organizations should also implement monitoring solutions to detect unusual patterns in OMAP operations or resource consumption that might indicate exploitation attempts. Network segmentation and access controls should be reinforced to limit the scope of potential attacks, ensuring that only authorized users have access to RGW endpoints. Additionally, regular security audits of Ceph configurations and monitoring of system logs for abnormal behavior patterns can help identify and respond to exploitation attempts before they cause significant disruption. This vulnerability aligns with CWE-400, which covers "Uncontrolled Resource Consumption" and is categorized under ATT&CK technique T1499.004 for "OS Cache Exhaustion" and T1566.001 for "Phishing" in scenarios where compromised credentials are used to exploit the vulnerability.