CVE-2007-3999 in Kerberos
Summary
by MITRE
Stack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) in MIT Kerberos 5 (krb5) 1.4 through 1.6.2, as used by the Kerberos administration daemon (kadmind) and some third-party applications that use krb5, allows remote attackers to cause a denial of service (daemon crash) and probably execute arbitrary code via a long string in an RPC message.
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Analysis
by VulDB Data Team • 01/11/2025
The vulnerability described in CVE-2007-3999 represents a critical stack-based buffer overflow within the RPCSEC_GSS implementation of MIT Kerberos 5 versions 1.4 through 1.6.2. This flaw exists in the svcauth_gss_validate function located in lib/rpc/svc_auth_gss.c, which forms a crucial component of the RPC library responsible for secure authentication in distributed systems. The vulnerability specifically affects the Kerberos administration daemon (kadmind) and any third-party applications that utilize the krb5 library for RPC communications. The flaw manifests when the function processes RPC messages containing excessively long strings, leading to unauthorized memory access patterns that can compromise system integrity and availability.
The technical exploitation of this vulnerability occurs through a classic stack-based buffer overflow mechanism where an attacker crafts an RPC message containing a string that exceeds the allocated buffer size within the svcauth_gss_validate function. This overflow enables attackers to overwrite adjacent memory locations on the stack, potentially corrupting program execution flow and allowing for arbitrary code execution. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow, which directly maps to the ATT&CK technique T1059.007 for execution through RPC services. The attack vector requires remote network access to the affected RPC services, making it particularly dangerous for systems exposed to untrusted networks or internet-facing services.
The operational impact of CVE-2007-3999 extends beyond simple denial of service scenarios to encompass potential complete system compromise. When exploited, the vulnerability can cause daemon crashes that disrupt Kerberos authentication services, effectively rendering the authentication infrastructure unavailable to legitimate users. However, the more severe implications involve code execution capabilities that could allow attackers to gain unauthorized access to systems running vulnerable versions of MIT Kerberos. This compromise can lead to privilege escalation, data theft, and further lateral movement within network environments where Kerberos is deployed. The vulnerability affects critical infrastructure components that rely on Kerberos for secure authentication, including Active Directory domains, network services, and enterprise authentication systems.
Mitigation strategies for this vulnerability require immediate patching of all affected MIT Kerberos 5 installations to versions 1.6.3 or later, which contain the necessary fixes for the buffer overflow condition. Organizations should also implement network segmentation to limit access to RPC services and establish monitoring for suspicious RPC traffic patterns. The implementation of proper input validation and bounds checking within RPC message processing can provide additional defense-in-depth measures. Security teams should conduct comprehensive vulnerability assessments to identify all systems running affected krb5 versions and ensure that the RPCSEC_GSS functionality is properly secured. Additionally, network access controls should be enforced to restrict RPC service access to trusted hosts only, reducing the attack surface for this particular vulnerability. Regular security updates and patch management procedures should be strengthened to prevent similar issues in the future, particularly focusing on the RPC subsystem components that handle authentication and authorization functions.