CVE-2000-0389 in Kerberos
Summary
by MITRE
Buffer overflow in krb_rd_req function in Kerberos 4 and 5 allows remote attackers to gain root privileges.
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Analysis
by VulDB Data Team • 07/04/2024
The vulnerability identified as CVE-2000-0389 represents a critical buffer overflow flaw within the Kerberos authentication systems, specifically affecting both Kerberos 4 and Kerberos 5 implementations. This vulnerability resides in the krb_rd_req function which processes authentication requests, making it a fundamental component in the authentication pipeline that handles ticket validation and access control. The flaw originates from insufficient input validation and improper buffer management when processing authentication tokens, creating an exploitable condition that can be leveraged by remote attackers to execute arbitrary code with elevated privileges.
The technical nature of this vulnerability stems from a classic buffer overflow condition where attacker-controlled input exceeds the allocated buffer space within the krb_rd_req function. When Kerberos servers process authentication requests containing maliciously crafted data, the insufficient bounds checking allows the overflow to overwrite adjacent memory locations including return addresses and control data. This memory corruption enables attackers to redirect program execution flow and ultimately execute malicious code with the privileges of the target service. The vulnerability is particularly severe because Kerberos implementations typically run with elevated privileges, often as system services or daemons, meaning successful exploitation can result in complete system compromise and root access.
From an operational perspective, this vulnerability presents a significant threat to network security infrastructure that relies on Kerberos authentication, which was widely adopted in enterprise environments and Unix-based systems during the late 1990s and early 2000s. Attackers can exploit this vulnerability remotely without requiring prior authentication, making it particularly dangerous for systems that expose Kerberos services to external networks. The impact extends beyond individual system compromise to potentially enable lateral movement within networks where Kerberos is used for single sign-on and cross-domain authentication. This vulnerability directly aligns with CWE-121, which categorizes buffer overflow conditions, and represents a prime example of how authentication system flaws can create privilege escalation pathways that bypass traditional security controls.
The exploitation of CVE-2000-0389 demonstrates the critical importance of proper input validation and memory management in security-critical code. Organizations using affected Kerberos implementations should immediately apply vendor patches and updates, as well as implement network segmentation to limit exposure of Kerberos services to untrusted networks. Security monitoring should focus on detecting anomalous authentication patterns and unusual network traffic to Kerberos servers. Additionally, system administrators should conduct comprehensive vulnerability assessments of all Kerberos implementations and consider implementing alternative authentication mechanisms where possible. This vulnerability exemplifies the ATT&CK technique T1078 which describes valid accounts usage, as successful exploitation would allow attackers to gain system-level privileges through compromised authentication services, potentially enabling further reconnaissance and persistence activities within the target environment.