CVE-2003-0269 in Youbin
Summary
by MITRE
Buffer overflow in youbin allows local users to gain privileges via a long HOME environment variable.
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Analysis
by VulDB Data Team • 08/27/2024
The vulnerability identified as CVE-2003-0269 represents a classic buffer overflow flaw in the youbin utility that affects Unix-like operating systems. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The youbin utility, typically used for handling binary data processing within certain system environments, fails to properly validate the length of the HOME environment variable before processing it, creating an exploitable condition that can be leveraged by local attackers.
The technical implementation of this vulnerability occurs when a local user manipulates the HOME environment variable to exceed the allocated buffer size within the youbin application. This buffer overflow allows the attacker to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical control data structures. The flaw is particularly dangerous because it operates within the context of a local user account, meaning that exploitation does not require network access or special privileges beyond what a regular user already possesses. The vulnerability is classified as a local privilege escalation vector because successful exploitation can allow a regular user to execute arbitrary code with elevated privileges, potentially reaching root access levels.
The operational impact of CVE-2003-0269 extends beyond simple local privilege escalation as it represents a fundamental security weakness in system utility design that can be exploited through environment variable manipulation. Attackers can leverage this vulnerability by setting a specially crafted HOME environment variable that exceeds the buffer capacity, causing the program to overwrite memory in a controlled manner. This approach aligns with the ATT&CK framework's privilege escalation techniques, specifically targeting the 'Exploitation for Privilege Escalation' tactic under the privilege escalation phase. The vulnerability demonstrates poor input validation practices and inadequate memory management within the youbin utility, creating a persistent security risk that affects systems where this utility is installed and executed with elevated privileges.
Mitigation strategies for this vulnerability should focus on immediate code-level fixes including implementing proper bounds checking for environment variable inputs, using safe string handling functions that prevent buffer overflows, and ensuring that all input data is validated before processing. System administrators should also implement environment variable restrictions where possible, particularly limiting the length and content of HOME variables that can be passed to sensitive utilities. The solution aligns with security best practices outlined in the OWASP Top Ten and other industry standards that emphasize input validation and secure coding practices. Additionally, regular security audits and code reviews should be conducted to identify similar buffer overflow vulnerabilities in other system utilities, as this represents a common class of flaws that can be systematically addressed through proper defensive programming techniques and adherence to secure coding guidelines.