CVE-2005-1689 in Kerberos
Summary
by MITRE
Double free vulnerability in the krb5_recvauth function in MIT Kerberos 5 (krb5) 1.4.1 and earlier allows remote attackers to execute arbitrary code via certain error conditions.
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Analysis
by VulDB Data Team • 01/19/2025
The CVE-2005-1689 vulnerability represents a critical double free condition within the krb5_recvauth function of MIT Kerberos 5 version 1.4.1 and earlier implementations. This flaw exists in the authentication handling mechanism of the Kerberos network authentication protocol, which is widely deployed across enterprise environments for secure single sign-on and network access control. The vulnerability arises from improper memory management practices where the same memory block gets freed twice under specific error conditions during the authentication process, creating a potential exploitation vector for remote attackers.
The technical implementation of this vulnerability stems from the krb5_recvauth function's failure to properly validate memory allocation states when processing authentication messages. When certain error conditions occur during the reception of authentication tokens, the function attempts to free memory resources that have already been released, leading to a double free scenario. This memory corruption condition can be exploited by attackers who craft malicious authentication requests that trigger the specific error paths within the authentication flow. The flaw is particularly dangerous because it occurs during the authentication handshake process, which is a fundamental operation in Kerberos-based systems.
The operational impact of CVE-2005-1689 extends beyond simple system instability, as it provides remote attackers with the capability to execute arbitrary code on vulnerable systems. This represents a severe privilege escalation vulnerability since Kerberos servers typically operate with elevated privileges to manage authentication services. Attackers can leverage this vulnerability to gain unauthorized access to network resources, potentially compromising entire authentication domains. The attack surface is broad as any system running MIT Kerberos 5 versions 1.4.1 or earlier that accepts authentication requests becomes a potential target, including domain controllers, file servers, and network infrastructure components that rely on Kerberos for authentication.
This vulnerability aligns with CWE-415, which specifically addresses double free conditions in memory management, and demonstrates how improper resource handling can lead to remote code execution. From an adversarial perspective, this flaw maps to ATT&CK technique T1550.001, which involves using valid accounts to access network services through Kerberos authentication. The vulnerability's exploitation requires minimal network access and can be automated, making it particularly attractive to threat actors targeting enterprise environments. Organizations using outdated Kerberos implementations face significant risk as this vulnerability has existed for over a decade and was not properly addressed in the affected versions.
Mitigation strategies for CVE-2005-1689 primarily involve immediate patching of affected MIT Kerberos installations to versions 1.4.2 and later, which contain the necessary memory management fixes. System administrators should also implement network segmentation to limit exposure of Kerberos services and monitor authentication logs for suspicious activities. Additional defensive measures include implementing proper access controls, regularly updating authentication infrastructure, and conducting vulnerability assessments to identify other potentially affected systems. The remediation process requires careful testing to ensure that the patch does not disrupt existing authentication workflows while maintaining the security posture of the network infrastructure.