CVE-2003-1537 in PostNuke
Summary
by MITRE
Directory traversal vulnerability in PostNuke 0.723 and earlier allows remote attackers to include arbitrary files named theme.php via the theme parameter to index.php.
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Analysis
by VulDB Data Team • 07/13/2025
The vulnerability described in CVE-2003-1537 represents a critical directory traversal flaw affecting PostNuke versions 0.723 and earlier. This vulnerability resides in the application's handling of user-supplied input through the theme parameter in the index.php file, creating a pathway for remote attackers to access arbitrary files on the server. The flaw stems from insufficient input validation and sanitization mechanisms that fail to properly restrict file access paths, allowing malicious users to manipulate the theme parameter to traverse directories and include unauthorized files. Such vulnerabilities typically arise from poor security practices in web application development where dynamic file inclusion functions are used without proper authorization checks or path validation.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious payload that includes directory traversal sequences such as ../ or ..\ in the theme parameter. When the vulnerable PostNuke application processes this input, it fails to validate the file path before including the specified file, potentially allowing access to sensitive system files, configuration data, or other unauthorized resources. The specific target file mentioned as theme.php suggests that the vulnerability is particularly dangerous because theme files often contain executable code and may be stored in directories with elevated privileges or contain sensitive configuration information. This type of 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 operational impact of CVE-2003-1537 extends beyond simple file disclosure, as it can potentially lead to complete system compromise when combined with other attack vectors. Remote attackers could leverage this vulnerability to execute arbitrary code on the target server, escalate privileges, or gain unauthorized access to sensitive data stored within the application's directory structure. The vulnerability's remote nature means that attackers do not require physical access to the system and can exploit it from anywhere on the internet, making it particularly dangerous for publicly accessible web applications. This flaw falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, where attackers can execute malicious code through vulnerable file inclusion mechanisms, and T1566 for Phishing, as attackers may use this vulnerability as part of a broader attack chain targeting web applications.
Mitigation strategies for CVE-2003-1537 should focus on immediate patching of the affected PostNuke installations to version 0.724 or later, which contains the necessary security fixes. Organizations should implement proper input validation and sanitization measures that reject any input containing directory traversal sequences, particularly when dealing with file inclusion operations. The application should enforce strict file path validation and use whitelisting approaches for theme selection, ensuring that only authorized themes can be loaded. Additionally, implementing proper access controls and privilege separation can limit the damage that could result from successful exploitation. Security configurations should include disabling dangerous PHP functions such as include, require, and their variants when user input is involved, and maintaining comprehensive logging to detect suspicious file access patterns. Regular security audits and vulnerability assessments should be conducted to identify similar flaws in other web applications and ensure that proper security practices are maintained throughout the software development lifecycle.