CVE-2012-1012 in Kerberos
Summary
by MITRE
server/server_stubs.c in the kadmin protocol implementation in MIT Kerberos 5 (aka krb5) 1.10 before 1.10.1 does not properly restrict access to (1) SET_STRING and (2) GET_STRINGS operations, which might allow remote authenticated administrators to modify or read string attributes by leveraging the global list privilege.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability described in CVE-2012-1012 resides within the kadmin protocol implementation of MIT Kerberos 5 version 1.10 before 1.10.1, specifically in the server_stubs.c file. This issue represents a critical access control flaw that undermines the security model of the Kerberos authentication system. The vulnerability affects the privilege management mechanisms within the kadmin protocol, which is responsible for administrative operations within Kerberos environments. The flaw stems from inadequate validation of access permissions for specific administrative operations that should be restricted to authorized administrators only.
The technical flaw manifests in the improper restriction of access to two critical operations: SET_STRING and GET_STRINGS within the kadmin protocol implementation. These operations are designed to manipulate string attributes within the Kerberos database, which typically contain sensitive configuration data and administrative parameters. The vulnerability allows authenticated administrators with global list privileges to bypass normal access controls and perform unauthorized modifications or read operations on string attributes that should normally be protected. This represents a privilege escalation issue where existing administrative access can be leveraged to gain broader control over the Kerberos database.
The operational impact of this vulnerability is significant for organizations relying on MIT Kerberos for authentication and authorization services. An attacker who has obtained legitimate administrative credentials can exploit this flaw to modify critical string attributes within the Kerberos database, potentially compromising the integrity of authentication services. This could lead to unauthorized access to protected resources, disruption of authentication services, or the establishment of persistent backdoors within the Kerberos infrastructure. The vulnerability affects the fundamental trust model of the Kerberos system, as it allows for unauthorized modification of configuration parameters that control access to various network services.
The security implications extend beyond simple privilege escalation, as this vulnerability can be exploited to manipulate the Kerberos database in ways that could compromise the entire authentication infrastructure. Attackers could modify string attributes to alter service principal configurations, change administrative access controls, or corrupt database integrity. This vulnerability aligns with CWE-284, which addresses improper access control, and can be mapped to ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting. Organizations using affected versions of MIT Kerberos should immediately implement mitigations including applying the official patches, reviewing access controls for kadmin operations, and monitoring for unauthorized database modifications. The vulnerability demonstrates the critical importance of proper access control implementation in authentication systems and highlights the potential for privilege escalation attacks within well-established security frameworks.