CVE-2014-4342 in Kerberos
Summary
by MITRE
MIT Kerberos 5 (aka krb5) 1.7.x through 1.12.x before 1.12.2 allows remote attackers to cause a denial of service (buffer over-read or NULL pointer dereference, and application crash) by injecting invalid tokens into a GSSAPI application session.
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Analysis
by VulDB Data Team • 02/10/2022
The vulnerability identified as CVE-2014-4342 represents a critical security flaw in MIT Kerberos 5 implementations across versions 1.7.x through 1.12.x, specifically before the release of 1.12.2. This issue affects the GSSAPI (Generic Security Services Application Program Interface) component of the Kerberos authentication system, which is widely deployed in enterprise environments for secure network authentication. The vulnerability stems from inadequate input validation mechanisms within the GSSAPI token processing routines, creating a pathway for remote attackers to manipulate authentication sessions through carefully crafted malicious inputs.
The technical exploitation of this vulnerability manifests through buffer over-read conditions or NULL pointer dereferences when the Kerberos implementation processes malformed GSSAPI tokens. These conditions occur during the parsing and validation of security tokens exchanged between clients and servers in the authentication process. When an attacker injects invalid tokens into an active GSSAPI application session, the vulnerable Kerberos implementation fails to properly handle the malformed data structures, leading to memory access violations that result in application crashes. The underlying flaw resides in the insufficient bounds checking and error handling within the token processing code, which does not adequately validate the integrity and format of incoming security tokens before attempting to parse them.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged by attackers to disrupt critical authentication services within enterprise networks. Organizations relying on Kerberos for single sign-on functionality, network access control, and service authentication face significant risk when exposed to this vulnerability. The remote nature of the attack means that adversaries can exploit the flaw from outside the network perimeter, potentially compromising the availability of authentication services that many applications and systems depend upon. This vulnerability particularly affects environments where Kerberos is used for authentication in protocols such as LDAP, HTTP, and other services that utilize GSSAPI for security token handling.
The vulnerability aligns with CWE-121, which describes "Stack-based Buffer Overflow" and CWE-476, which covers "NULL Pointer Dereference" as the underlying technical causes of the issue. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, "Endpoint Denial of Service," and potentially T1566.001, "Phishing via Service" if attackers use it to disrupt services during credential theft attempts. Organizations should implement immediate mitigations including updating to Kerberos 1.12.2 or later versions, implementing network segmentation to limit exposure, and monitoring for unusual authentication session behavior. Additionally, administrators should consider implementing intrusion detection systems that can identify malformed GSSAPI token patterns and ensure that all Kerberos implementations undergo regular security assessments to prevent similar vulnerabilities from emerging in future releases.