CVE-2007-5902 in Kerberos
Summary
by MITRE
Integer overflow in the svcauth_gss_get_principal function in lib/rpc/svc_auth_gss.c in MIT Kerberos 5 (krb5) allows remote attackers to have an unknown impact via a large length value for a GSS client name in an RPC request.
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Analysis
by VulDB Data Team • 07/29/2021
The vulnerability described in CVE-2007-5902 represents a critical integer overflow condition within the MIT Kerberos 5 implementation that affects the svcauth_gss_get_principal function. This flaw exists in the lib/rpc/svc_auth_gss.c file and specifically targets the handling of GSS client names within RPC requests. The vulnerability arises when the system processes a malformed RPC request containing an excessively large length value for the GSS client name parameter, creating a scenario where integer arithmetic operations exceed the maximum representable value for the data type being used. This condition falls under the CWE-190 category of Integer Overflow or Wraparound, which is classified as a fundamental weakness in software design that can lead to severe security implications.
The technical exploitation of this vulnerability occurs during the authentication process when the svcauth_gss_get_principal function attempts to process the client name length field. When an attacker sends an RPC request with a deliberately crafted large length value, the function's integer arithmetic operations overflow, potentially causing memory corruption or unexpected behavior in the Kerberos service. The overflow can lead to buffer overflows, memory access violations, or other undefined behaviors that may be leveraged by malicious actors to execute arbitrary code or cause denial of service conditions. The impact remains unspecified in the original CVE description, but such integer overflow conditions in authentication modules typically represent high-risk scenarios that could compromise the integrity of the entire Kerberos authentication infrastructure.
From an operational perspective, this vulnerability presents significant risks to systems relying on MIT Kerberos 5 for authentication services, particularly those using RPC mechanisms for inter-service communication. The remote nature of the attack means that adversaries can exploit this flaw without requiring local access to the target system, making it particularly dangerous in networked environments where Kerberos services are exposed to untrusted networks. The vulnerability affects the core authentication functionality of Kerberos, potentially allowing attackers to bypass authentication mechanisms or gain unauthorized access to protected resources. This type of flaw is particularly concerning when considering that Kerberos is widely deployed in enterprise environments, cloud infrastructures, and distributed systems where secure authentication is paramount. The attack vector aligns with ATT&CK technique T1550.001 for use of Kerberos and T1071.004 for application layer protocol usage, representing a sophisticated attack path that targets foundational security infrastructure.
The mitigation strategies for CVE-2007-5902 should focus on immediate patching of affected MIT Kerberos 5 implementations, as this vulnerability represents a known flaw that has been addressed in subsequent releases. Organizations should implement network segmentation and access controls to limit exposure of Kerberos services to untrusted networks, while also monitoring for suspicious RPC traffic patterns that might indicate exploitation attempts. Input validation measures should be strengthened to reject malformed length values before they reach the vulnerable function, and proper bounds checking should be implemented throughout the authentication processing pipeline. The vulnerability demonstrates the importance of rigorous input validation and integer overflow protection in security-critical code, particularly within cryptographic and authentication modules. Regular security assessments and code reviews focusing on integer handling and memory management should be conducted to identify similar vulnerabilities in other components of the system infrastructure. Additionally, implementing intrusion detection systems that can identify anomalous RPC request patterns may provide early warning of exploitation attempts targeting this class of vulnerability.