CVE-2002-1235 in Kerberos
Summary
by MITRE
The kadm_ser_in function in (1) the Kerberos v4compatibility administration daemon (kadmind4) in the MIT Kerberos 5 (krb5) krb5-1.2.6 and earlier, (2) kadmind in KTH Kerberos 4 (eBones) before 1.2.1, and (3) kadmind in KTH Kerberos 5 (Heimdal) before 0.5.1 when compiled with Kerberos 4 support, does not properly verify the length field of a request, which allows remote attackers to execute arbitrary code via a buffer overflow attack.
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Analysis
by VulDB Data Team • 09/07/2025
The vulnerability identified as CVE-2002-1235 represents a critical buffer overflow flaw within the Kerberos authentication system's administration daemon components. This issue affects multiple Kerberos implementations including MIT Kerberos 5 versions up to 1.2.6, KTH Kerberos 4 versions prior to 1.2.1, and Heimdal Kerberos 5 versions before 0.5.1 when compiled with Kerberos 4 compatibility support. The flaw resides in the kadm_ser_in function which processes administrative requests for Kerberos database modifications, making it a prime target for remote exploitation attacks.
The technical implementation of this vulnerability stems from inadequate input validation within the kadm_ser_in function where the length field of incoming requests is not properly verified before processing. When a maliciously crafted request is sent to the affected daemon, the system fails to validate that the specified length field corresponds to the actual data size being transmitted. This discrepancy allows attackers to construct requests with oversized length fields, causing the daemon to write data beyond the allocated buffer boundaries. The buffer overflow occurs because the system assumes the length field accurately represents the data size and proceeds to copy data without proper bounds checking, leading to memory corruption that can be exploited to execute arbitrary code.
The operational impact of this vulnerability is severe as it provides remote attackers with the capability to gain arbitrary code execution privileges on systems running the affected Kerberos administration daemons. Since kadmind services typically run with elevated privileges to manage authentication databases, successful exploitation could result in complete system compromise, unauthorized access to authentication credentials, and potential lateral movement within network environments. The vulnerability affects the core administrative functionality of Kerberos systems, undermining the security infrastructure that organizations rely upon for secure authentication and authorization services. Organizations using these vulnerable versions face significant risk of unauthorized access to their authentication systems, potentially leading to data breaches and service disruption.
Mitigation strategies for CVE-2002-1235 involve immediate patching of all affected Kerberos implementations to their respective secure versions. System administrators should upgrade to MIT Kerberos 5 1.2.7 or later, KTH Kerberos 4 1.2.1 or later, and Heimdal Kerberos 5 0.5.1 or later. Additionally, network segmentation and firewall rules should be implemented to restrict access to kadmind ports, typically port 749 for Kerberos administration. The vulnerability aligns with CWE-121 and CWE-122 categories related to stack-based and heap-based buffer overflows, and represents a technique commonly referenced in ATT&CK framework under T1059 for execution and T1566 for credential access. Organizations should also implement intrusion detection systems to monitor for suspicious administrative requests and establish monitoring procedures to detect potential exploitation attempts against their Kerberos infrastructure.