CVE-2006-3207 in Ultimate PHP Board
Summary
by MITRE
Directory traversal vulnerability in newpost.php in Ultimate PHP Board (UPB) 1.9.6 and earlier allows remote attackers to overwrite arbitrary files via a .. (dot dot) sequence and trailing null (%00) byte in the id parameter, as demonstrated by injecting a Perl CGI script using "[NR]" sequences in the message parameter, then calling close.php with modified id and t_id parameters to chmod the script. NOTE: this issue might be resultant from dynamic variable evaluation.
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Analysis
by VulDB Data Team • 09/18/2017
The vulnerability identified as CVE-2006-3207 represents a critical directory traversal flaw within the Ultimate PHP Board (UPB) version 1.9.6 and earlier implementations. This security weakness specifically resides in the newpost.php script which fails to properly validate user input parameters, creating an exploitable condition that allows remote attackers to manipulate file system operations. The vulnerability manifests through the manipulation of the id parameter, where attackers can utilize the .. (dot dot) sequence combined with trailing null (%00) bytes to navigate outside the intended directory structure and access arbitrary files on the server. This directory traversal capability stems from inadequate input sanitization and validation mechanisms within the UPB application's file handling processes.
The technical exploitation of this vulnerability involves a multi-stage attack vector that begins with the injection of malicious content through the message parameter using "[NR]" sequences to create Perl CGI scripts. The attacker then leverages the directory traversal to overwrite existing files with malicious content, subsequently calling close.php with modified id and t_id parameters to execute chmod operations on the injected script. This sequence demonstrates a sophisticated attack pattern that combines file system manipulation with privilege escalation techniques, enabling attackers to potentially execute arbitrary code on the target server. The vulnerability's classification as a directory traversal issue aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of this vulnerability extends beyond simple file access, as it provides attackers with the capability to overwrite critical system files, inject malicious code, and potentially establish persistent backdoors within the affected web application. The use of dynamic variable evaluation within the UPB framework exacerbates the risk, as it allows attackers to manipulate internal application variables through crafted input, leading to unauthorized file system modifications. This vulnerability creates a significant risk for web applications running UPB versions prior to the patched release, as it can be exploited remotely without requiring authentication or special privileges. The attack can result in complete compromise of the web server, data theft, service disruption, and potential lateral movement within the network infrastructure.
Security mitigations for CVE-2006-3207 should focus on implementing robust input validation and sanitization measures within the UPB application. The primary remediation involves proper parameter validation in the newpost.php script to prevent directory traversal sequences and null byte injection attempts. Organizations should ensure that all user-supplied input is strictly validated against allowed character sets and patterns, with special attention to preventing sequences that could manipulate file paths. Additionally, implementing proper access controls and file system permissions can limit the impact of successful exploitation attempts. The solution should include disabling dynamic variable evaluation where possible and implementing proper output encoding for all user-controllable data. Security patches should be applied immediately to upgrade to UPB versions that address this vulnerability, while network monitoring should be enhanced to detect suspicious file system access patterns. This vulnerability also highlights the importance of following secure coding practices and adhering to the principle of least privilege when developing web applications, as outlined in various security frameworks including the OWASP Top Ten and NIST cybersecurity guidelines.