CVE-2007-5894 in Kerberos
Summary
by MITRE
** DISPUTED ** The reply function in ftpd.c in the gssftp ftpd in MIT Kerberos 5 (krb5) does not initialize the length variable when auth_type has a certain value, which has unknown impact and remote authenticated attack vectors. NOTE: the original disclosure misidentifies the conditions under which the uninitialized variable is used. NOTE: the vendor disputes this issue, stating " The length variable is only uninitialized if auth_type is neither the KERBEROS_V4 nor GSSAPI ; this condition cannot occur in the unmodified source code."
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability described in CVE-2007-5894 pertains to a potential uninitialized variable issue within the ftpd.c component of MIT Kerberos 5's gssftp implementation. This flaw exists in the reply function where a length variable fails to be properly initialized when the auth_type parameter assumes specific values. The vulnerability classification as disputed reflects the vendor's position that the condition leading to the uninitialized variable cannot occur in properly maintained source code, creating uncertainty about the actual exploitability of this issue. The technical nature of this vulnerability falls under the category of uninitialized variable usage, which is categorized as CWE-457 in the Common Weakness Enumeration system, representing a significant security concern due to potential memory corruption or information disclosure risks.
The operational impact of this vulnerability remains ambiguous due to the disputed nature of the issue and the vendor's assertion that the problematic condition cannot occur in standard configurations. However, the potential for remote authenticated attack vectors suggests that an attacker with valid credentials could potentially exploit this flaw to manipulate program execution or extract sensitive information from memory. The authentication requirement indicates that this vulnerability would not be exploitable by anonymous users, but rather by legitimate authenticated users who have access to the ftpd service. This scenario aligns with ATT&CK technique T1078 which covers valid accounts as a means of gaining access to systems, though the specific exploitation path remains unclear due to the disputed status of the vulnerability.
The vendor's response dismissing the issue highlights a critical aspect of vulnerability assessment where the distinction between theoretical flaws and practical exploitability becomes crucial. MIT's assertion that the auth_type cannot assume the problematic values in unmodified source code suggests that any legitimate installation would not encounter this condition, making the vulnerability effectively non-existent in properly configured environments. This situation demonstrates the importance of understanding the complete context of vulnerability disclosures, as the original reporting may have contained inaccuracies regarding the specific conditions required for exploitation. The disputed nature of this CVE also underscores the challenges faced by security researchers and organizations in properly categorizing and assessing vulnerabilities that may not manifest in all deployment scenarios.
While the vulnerability remains disputed and potentially non-exploitable in standard configurations, the presence of uninitialized variable issues in network services represents a broader security concern that warrants attention. The gssftp service's operation within the Kerberos authentication framework means that any flaw in this component could potentially affect authentication integrity and overall system security. Organizations should ensure that their Kerberos implementations are properly maintained and updated according to vendor guidelines, as the disputed nature of this vulnerability does not necessarily indicate that similar issues cannot exist in other components of the software stack. The incident serves as a reminder of the complexity involved in vulnerability assessment and the necessity of thorough testing in various deployment scenarios to properly understand security risks.