CVE-2012-1013 in Kerberos
Summary
by MITRE
The check_1_6_dummy function in lib/kadm5/srv/svr_principal.c in kadmind in MIT Kerberos 5 (aka krb5) 1.8.x, 1.9.x, and 1.10.x before 1.10.2 allows remote authenticated administrators to cause a denial of service (NULL pointer dereference and daemon crash) via a KRB5_KDB_DISALLOW_ALL_TIX create request that lacks a password.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability described in CVE-2012-1013 represents a critical denial of service weakness within the MIT Kerberos 5 implementation that affects multiple versions including 1.8.x, 1.9.x, and 1.10.x before 1.10.2. This flaw specifically targets the kadmind daemon which serves as the key distribution center for Kerberos authentication services. The vulnerability exists within the check_1_6_dummy function located in the server principal handling component of the Kerberos administration module, making it accessible to authenticated administrators who can leverage this weakness to disrupt service availability.
The technical exploitation of this vulnerability occurs through a specific manipulation of the KRB5_KDB_DISALLOW_ALL_TIX create request mechanism. When an authenticated administrator submits such a request without providing a required password parameter, the system encounters a NULL pointer dereference condition within the check_1_6_dummy function. This programming error causes the kadmind daemon to crash and terminate unexpectedly, effectively removing the Kerberos authentication service from operation. The flaw stems from inadequate input validation and error handling within the administrative request processing pipeline, particularly when dealing with principal creation operations that should require password specifications for security reasons.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged by malicious administrators or compromised accounts to systematically degrade the availability of Kerberos authentication services across an organization. This denial of service condition affects the core authentication infrastructure that many enterprise systems depend upon for secure access control, potentially impacting authentication for services such as file servers, database access, and networked applications that rely on Kerberos tickets for secure communication. The vulnerability demonstrates a weakness in the privilege escalation and administrative request validation mechanisms within the Kerberos implementation, creating a scenario where authenticated users can cause system-wide service interruptions.
Mitigation strategies for CVE-2012-1013 should focus on immediate patching of affected Kerberos versions to 1.10.2 or later releases that contain the necessary code fixes for proper input validation. Organizations should also implement monitoring of administrative authentication requests to detect unusual patterns that might indicate exploitation attempts, particularly those involving principal creation requests without required password parameters. The vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, and represents a specific instance where improper error handling in administrative interfaces can be exploited for denial of service attacks. From an ATT&CK framework perspective, this vulnerability maps to techniques involving service stoppage and denial of service operations that target critical infrastructure components, making it particularly dangerous in enterprise environments where Kerberos serves as a foundational authentication service.