CVE-2006-3319 in PHP iCalendar
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in rss/index.php in PHP iCalendar 2.22 and earlier allows remote attackers to inject arbitrary web script or HTML via the cal parameter.
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Analysis
by VulDB Data Team • 09/18/2017
The CVE-2006-3319 vulnerability represents a classic cross-site scripting flaw within the PHP iCalendar application version 2.22 and earlier. This vulnerability specifically targets the rss/index.php script where user input is not properly sanitized before being rendered in web pages. The affected parameter is named cal, which suggests it likely handles calendar-related data or configuration parameters. Attackers can exploit this weakness by injecting malicious javascript code or html content through the cal parameter, which then gets executed in the context of other users' browsers who visit the affected calendar pages.
The technical nature of this vulnerability aligns with CWE-79 which defines Cross-Site Scripting as a code injection attack where malicious scripts are executed in the victim's browser. This particular implementation demonstrates a failure in input validation and output encoding practices within the PHP iCalendar application. The vulnerability occurs because the application does not adequately filter or escape user-supplied input before incorporating it into dynamically generated web content. This creates an environment where attackers can craft malicious payloads that persist in the application's data storage or execution flow, ultimately executing in the browsers of unsuspecting users.
The operational impact of CVE-2006-3319 extends beyond simple script injection, as it can enable attackers to perform various malicious activities including session hijacking, credential theft, redirection to malicious sites, and data exfiltration. When calendar applications are used in enterprise environments or by users with administrative privileges, the potential for damage increases significantly. Attackers could exploit this vulnerability to steal user sessions, modify calendar entries, or redirect users to phishing sites that appear legitimate. The vulnerability affects the core functionality of calendar management systems, making it particularly dangerous for organizations that rely on calendar sharing and collaboration features. Additionally, since this was a widespread issue in calendar applications, it could have been leveraged in large-scale attacks against multiple users simultaneously.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and output encoding mechanisms. Organizations should immediately upgrade to PHP iCalendar version 2.23 or later where this vulnerability has been addressed through proper input sanitization. The fix typically involves implementing proper escaping of user input before rendering it in web pages, using functions such as htmlspecialchars in php or similar encoding mechanisms in other languages. Security measures should include validating all user input parameters, implementing Content Security Policies to limit script execution, and conducting regular security audits of web applications. The vulnerability also highlights the importance of following secure coding practices as outlined in OWASP Top 10 and other industry standards, emphasizing the need for input validation and output encoding in web application development. Furthermore, implementing web application firewalls and monitoring for suspicious parameter values can provide additional layers of protection against such attacks.