CVE-2013-4134 in OpenAFS
Summary
by MITRE
OpenAFS before 1.4.15, 1.6.x before 1.6.5, and 1.7.x before 1.7.26 uses weak encryption (DES) for Kerberos keys, which makes it easier for remote attackers to obtain the service key.
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Analysis
by VulDB Data Team • 01/10/2022
The vulnerability described in CVE-2013-4134 represents a critical cryptographic weakness in the OpenAFS distributed file system implementation that affects multiple version branches including 1.4.15, 1.6.x through 1.6.4, and 1.7.x through 1.7.25. This flaw specifically targets the encryption mechanisms used for Kerberos service keys within the OpenAFS framework, creating a significant security risk that can be exploited by remote attackers to compromise authentication processes. The vulnerability stems from the use of DES encryption, which has been deprecated for decades due to its inherent weaknesses and susceptibility to various cryptographic attacks.
The technical implementation flaw lies in OpenAFS's reliance on DES encryption for Kerberos service key management rather than stronger encryption algorithms such as AES or 3DES. This weakness creates a pathway for attackers to perform dictionary attacks or brute force attempts against the service keys, significantly reducing the computational effort required to obtain valid service credentials. The vulnerability operates at the authentication layer where OpenAFS integrates with Kerberos authentication protocols, making it particularly dangerous as it undermines the fundamental security assumptions of the distributed authentication system. The use of DES encryption in this context directly violates modern cryptographic best practices and security standards.
The operational impact of this vulnerability extends beyond simple credential theft, as successful exploitation can lead to complete compromise of the OpenAFS infrastructure and the sensitive data it protects. Attackers who obtain valid service keys can gain unauthorized access to files and resources managed by the distributed file system, potentially leading to data exfiltration, privilege escalation, and persistent access to organizational networks. This vulnerability particularly affects organizations that rely on OpenAFS for file sharing and authentication services, especially those in government, academic, or enterprise environments where distributed file systems are commonly deployed. The remote nature of the attack vector means that adversaries do not require physical access or local network presence to exploit this weakness.
Organizations should implement immediate mitigation strategies including upgrading to patched versions of OpenAFS that utilize stronger encryption algorithms for Kerberos keys, typically through version 1.4.15, 1.6.5, or 1.7.26 and later releases. System administrators should also consider implementing additional monitoring and alerting mechanisms to detect potential exploitation attempts, particularly around authentication failures and unusual access patterns. The vulnerability aligns with CWE-327, which addresses the use of weak cryptographic algorithms, and maps to ATT&CK technique T1550.001 for use of stolen credentials and T1078.002 for valid accounts. Organizations should also review their Kerberos configuration settings to ensure that strong encryption types are enforced and that DES encryption is completely disabled within their OpenAFS deployments.