CVE-2017-11462 in Kerberos 5
Summary
by MITRE
Double free vulnerability in MIT Kerberos 5 (aka krb5) allows attackers to have unspecified impact via vectors involving automatic deletion of security contexts on error.
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Analysis
by VulDB Data Team • 12/28/2022
The double free vulnerability identified as CVE-2017-11462 affects MIT Kerberos 5 version 1.15 and earlier, representing a critical security flaw that can be exploited to compromise the integrity and availability of authentication systems. This vulnerability resides within the kerberos authentication framework that is widely deployed across enterprise environments and cloud infrastructures for secure network authentication. The flaw specifically manifests during error handling scenarios when security contexts are automatically deleted, creating conditions where memory management operations can be manipulated by malicious actors.
The technical implementation of this vulnerability stems from improper handling of memory allocation and deallocation sequences within the kerberos library's error recovery mechanisms. When certain error conditions occur during authentication processes, the system attempts to automatically clean up security contexts through a deletion routine that fails to properly track memory references. This oversight allows attackers to craft specific authentication requests that trigger the double free condition, where the same memory block gets deallocated twice, potentially leading to memory corruption. The vulnerability is particularly dangerous because it operates at the core of the authentication process, making it difficult to detect and exploit without proper monitoring and detection capabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and denial of service scenarios. Attackers can leverage this flaw to execute arbitrary code on systems running vulnerable kerberos implementations, potentially gaining access to sensitive network resources and authentication credentials. The unspecified impact mentioned in the CVE description reflects the broad range of potential consequences including complete system compromise, data exfiltration, and disruption of authentication services that could affect thousands of users within a domain. Organizations relying on kerberos for single sign-on, network authentication, and service access control face significant risk exposure when operating vulnerable versions of the software.
Mitigation strategies for CVE-2017-11462 require immediate patching of all affected kerberos installations to version 1.15.1 or later, which contains the necessary fixes to prevent the double free condition during error handling. System administrators should implement comprehensive monitoring solutions to detect anomalous authentication patterns that might indicate exploitation attempts, particularly focusing on error handling routines and memory allocation behaviors. The vulnerability aligns with CWE-415 which addresses double free conditions in memory management, and maps to attack techniques in the MITRE ATT&CK framework under privilege escalation and defense evasion categories. Organizations should also conduct thorough vulnerability assessments to identify all systems utilizing kerberos authentication and ensure proper network segmentation to limit potential lateral movement if exploitation occurs. Regular security updates and patch management processes become critical for maintaining protection against similar memory corruption vulnerabilities in authentication systems.