CVE-2000-0332 in UltraBoard
Summary
by MITRE
UltraBoard.pl or UltraBoard.cgi CGI scripts in UltraBoard 1.6 allows remote attackers to read arbitrary files via a pathname string that includes a dot dot (..) and ends with a null byte.
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Analysis
by VulDB Data Team • 08/24/2024
The vulnerability identified as CVE-2000-0332 resides within the UltraBoard 1.6 web application, specifically targeting the UltraBoard.pl and UltraBoard.cgi CGI scripts that handle user input through pathname strings. This flaw represents a classic path traversal vulnerability that enables malicious actors to access files outside the intended directory structure. The vulnerability stems from inadequate input validation within the CGI scripts, which fail to properly sanitize user-supplied pathname parameters before processing them. When a malicious user submits a pathname string containing dot dot sequences followed by a null byte, the application fails to properly validate or sanitize the input, allowing the attacker to navigate beyond the intended directory boundaries and access arbitrary files on the server filesystem.
This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector leverages the null byte termination feature of certain programming languages to bypass input validation mechanisms that might otherwise detect the dot dot sequences. The exploitation technique involves crafting a malicious request where the pathname parameter contains sequences like "../" followed by a null byte character, which effectively terminates the string processing and allows the attacker to traverse the filesystem hierarchy. The vulnerability is particularly dangerous because it can be exploited to access sensitive system files, configuration data, and potentially user information that should remain protected within the application's restricted directory structure.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can lead to complete system compromise and data exfiltration. Attackers can leverage this vulnerability to access critical system files such as password files, configuration databases, application source code, and other sensitive information that may contain credentials, system configurations, or business logic. The null byte termination technique allows for bypassing many traditional input validation mechanisms that might detect the dot dot sequences but fail to account for null byte termination. This vulnerability can be exploited by remote attackers without requiring any authentication or local access, making it particularly dangerous for web applications that are publicly accessible. The attack can result in unauthorized access to sensitive data, potential privilege escalation, and in some cases, complete system compromise depending on the permissions of the web server process and the files that are accessible through the traversal.
Mitigation strategies for CVE-2000-0332 should focus on implementing proper input validation and sanitization mechanisms within the CGI scripts. The most effective approach involves implementing strict input validation that rejects any pathname strings containing dot dot sequences or other traversal patterns. Additionally, applications should employ proper path normalization techniques that resolve absolute paths and prevent directory traversal attacks. The implementation of a whitelist approach for acceptable file paths can also provide strong protection against this class of vulnerability. Organizations should also consider implementing web application firewalls that can detect and block suspicious pathname patterns, as well as ensuring that the web server is configured to prevent access to sensitive system files through directory traversal techniques. The vulnerability highlights the importance of following secure coding practices and input validation as outlined in the OWASP Top Ten and other industry security standards, particularly focusing on the prevention of path traversal attacks through proper application design and implementation. Regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities in other applications that may be susceptible to the same class of attack patterns.