CVE-2003-0060 in Kerberos
Summary
by MITRE
Format string vulnerabilities in the logging routines for MIT Kerberos V5 Key Distribution Center (KDC) before 1.2.5 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers in Kerberos principal names.
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Analysis
by VulDB Data Team • 11/18/2024
The vulnerability identified as CVE-2003-0060 represents a critical format string flaw within the logging mechanisms of MIT Kerberos V5 Key Distribution Center software versions prior to 1.2.5. This issue specifically affects the KDC component which serves as the central authentication server in Kerberos authentication systems, making it a prime target for attackers seeking to disrupt secure network environments. The vulnerability stems from improper handling of user-supplied input within the logging routines, creating a dangerous condition where attacker-controlled data can be interpreted as format specifiers rather than plain text.
The technical exploitation of this vulnerability occurs when remote attackers submit specially crafted Kerberos principal names containing format string specifiers such as %s, %d, or %x. These specifiers, when processed through insecure logging functions, can cause the KDC to read memory locations or execute unintended operations based on the attacker's input. The flaw manifests in the way the system handles principal names during authentication requests, where the logging subsystem fails to properly sanitize or escape the input before processing it as a format string. This type of vulnerability falls under the CWE-134 category of Use of Externally-Controlled Format String, which is classified as a high-risk vulnerability due to its potential for both denial of service and arbitrary code execution.
The operational impact of CVE-2003-0060 extends beyond simple service disruption, as it can lead to complete system compromise when exploited successfully. The denial of service aspect causes the KDC to crash and restart, effectively breaking Kerberos authentication for the entire domain or network segment relying on that particular KDC instance. This creates a cascading effect where legitimate users cannot authenticate, and the system becomes unavailable for legitimate operations. In more severe exploitation scenarios, attackers can potentially execute arbitrary code with the privileges of the KDC process, which typically runs with elevated permissions. This vulnerability directly aligns with ATT&CK technique T1078.002 for Valid Accounts and T1499.004 for Endpoint Denial of Service, making it particularly dangerous in enterprise environments where Kerberos is widely deployed.
Mitigation strategies for this vulnerability require immediate patching of all affected MIT Kerberos V5 installations to version 1.2.5 or later, which contains the necessary fixes for the format string handling in logging routines. Organizations should also implement network segmentation and monitoring to detect unusual authentication patterns that might indicate exploitation attempts. The fix involves proper input validation and sanitization of principal names before they are passed to logging functions, ensuring that any format specifiers are treated as literal characters rather than executable instructions. Security teams should also consider implementing intrusion detection systems that can identify potential format string exploitation attempts and establish comprehensive backup authentication mechanisms to maintain service availability during remediation efforts.