CVE-2018-1129 in Ceph
Summary
by MITRE
A flaw was found in the way signature calculation was handled by cephx authentication protocol. An attacker having access to ceph cluster network who is able to alter the message payload was able to bypass signature checks done by cephx protocol. Ceph branches master, mimic, luminous and jewel are believed to be vulnerable.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability described in CVE-2018-1129 represents a critical weakness in the Ceph distributed storage system's authentication mechanism, specifically within the cephx protocol implementation. This flaw resides in the signature calculation process that is fundamental to ensuring the integrity and authenticity of communications between clients and Ceph storage components. The cephx protocol serves as the primary authentication method for Ceph clusters, establishing trust relationships between various cluster components including monitors, OSDs, and clients. When properly functioning, this protocol validates that messages have not been tampered with during transmission and that they originate from legitimate sources within the cluster environment.
The technical flaw manifests as a vulnerability in how cryptographic signatures are computed and verified within the cephx authentication flow. Attackers who can intercept network traffic and modify message payloads are able to manipulate the signature calculation process in such a way that their altered communications bypass the protocol's integrity checks. This represents a classic example of a cryptographic weakness where the signature verification mechanism fails to properly validate the integrity of the message content, allowing for man-in-the-middle attacks or message tampering scenarios. The vulnerability specifically affects the signature generation algorithm used by cephx, which likely employs a hash-based message authentication code or similar cryptographic primitive that becomes susceptible to manipulation when certain conditions are met.
The operational impact of this vulnerability is severe for organizations relying on Ceph storage clusters, as it fundamentally undermines the security model of the entire system. An attacker who gains network access to a Ceph cluster can potentially manipulate storage operations, modify data, or even gain unauthorized access to storage resources by bypassing authentication checks. This vulnerability affects multiple Ceph release branches including master, mimic, luminous, and jewel, indicating it is a long-standing issue that has persisted across several versions of the software. The widespread impact across these branches suggests that the flaw is in core protocol implementation rather than being a recent regression, making it particularly concerning for organizations with legacy deployments.
The vulnerability aligns with CWE-310, which covers cryptographic issues such as weak cryptographic algorithms or improper implementation of cryptographic functions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and privilege escalation through network protocol manipulation. The attack vector requires network-level access and the ability to modify messages, which could be achieved through various means including network interception tools, compromised network devices, or insider threats. Organizations should consider implementing network segmentation, encryption of storage communications, and monitoring for unusual authentication patterns as mitigation strategies.
Mitigation efforts should focus on immediate patch deployment across all affected Ceph versions, along with network-level security measures to prevent unauthorized access to cluster communications. The fix typically involves correcting the signature calculation algorithm to properly validate message integrity before accepting authentication requests. Organizations should also implement additional monitoring for authentication failures and anomalous access patterns that might indicate exploitation attempts. Given the nature of the vulnerability, regular security assessments of Ceph deployments are recommended to ensure that proper cryptographic implementations are maintained across all cluster components. The vulnerability demonstrates the critical importance of proper cryptographic implementation in distributed systems where security relies heavily on authentication protocols to maintain data integrity and access control boundaries.