CVE-2004-0643 in Kerberos
Summary
by MITRE
Double free vulnerability in the krb5_rd_cred function for MIT Kerberos 5 (krb5) 1.3.1 and earlier may allow local users to execute arbitrary code.
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Analysis
by VulDB Data Team • 12/16/2024
The CVE-2004-0643 vulnerability represents a critical double free error in the krb5_rd_cred function within MIT Kerberos 5 versions 1.3.1 and earlier. This flaw exists within the Kerberos authentication system's credential processing mechanism, specifically when handling received credentials during the authentication process. The vulnerability stems from improper memory management where the same memory block gets freed twice, creating a condition that can be exploited by local attackers to gain arbitrary code execution privileges. Such a flaw is particularly dangerous because it occurs within the core authentication infrastructure that many systems rely upon for secure access control.
The technical implementation of this vulnerability involves the krb5_rd_cred function failing to properly validate or track memory allocations during credential processing. When malformed or specially crafted credentials are processed, the function executes a memory deallocation operation twice on the same memory pointer, leading to a heap corruption condition. This memory corruption can be manipulated by an attacker to overwrite critical program data structures or function pointers, ultimately allowing for code execution with the privileges of the targeted process. The double free condition creates a predictable pattern that can be exploited through carefully constructed input sequences, making it a particularly attractive target for local privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it affects the fundamental security of Kerberos-based authentication systems. Systems running vulnerable versions of MIT Kerberos 5 are at risk of being compromised by local users who can leverage this flaw to execute arbitrary code with elevated privileges. The vulnerability's local nature means that attackers do not require network access or complex exploitation techniques, making it particularly dangerous in environments where local access is possible. Organizations relying on Kerberos for authentication, including those using it for service accounts, administrative access, or network security infrastructure, face significant risk from this flaw.
Mitigation strategies for CVE-2004-0643 primarily focus on immediate patching of affected systems, with the recommended solution being the upgrade to MIT Kerberos 5 version 1.3.2 or later, which contains the necessary memory management fixes. System administrators should prioritize patching all affected systems, particularly those running Kerberos services or applications that depend on the vulnerable library functions. Additional protective measures include implementing proper access controls to limit local user privileges, monitoring for suspicious credential processing activities, and ensuring that Kerberos services are configured with appropriate security parameters. This vulnerability aligns with CWE-415, which describes improper double free conditions in memory management, and represents a classic example of how memory safety issues in cryptographic libraries can create severe security implications. The ATT&CK framework categorizes this as a privilege escalation technique, specifically targeting local user accounts to gain elevated system access through memory corruption vulnerabilities in authentication services. Organizations should also consider implementing network segmentation and privilege separation to minimize the potential impact of successful exploitation attempts.