CVE-2010-2041 in PHP-Calendar
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in index.php in PHP-Calendar before 2.0 Beta7 allow remote attackers to inject arbitrary web script or HTML via the (1) description and (2) lastaction parameters.
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Analysis
by VulDB Data Team • 02/05/2019
The vulnerability identified as CVE-2010-2041 represents a critical cross-site scripting flaw in PHP-Calendar version 2.0 Beta6 and earlier, demonstrating a classic weakness in input validation and output sanitization that has persisted across numerous web applications. This vulnerability exists within the index.php script and specifically targets two parameter fields: description and lastaction, which together create multiple attack vectors for malicious actors seeking to exploit the calendar application. The flaw stems from the application's failure to properly sanitize user-supplied input before rendering it within the web page context, creating an environment where attacker-controlled content can be executed in the context of other users' browsers.
The technical implementation of this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications. The flaw occurs when user input flows directly into HTML output without proper encoding or sanitization, allowing attackers to inject malicious scripts that execute in the victim's browser. The description parameter and lastaction parameter both serve as entry points where unfiltered user input can be manipulated to include script tags or other malicious HTML content. This particular implementation demonstrates a common pattern where web applications fail to implement proper input validation at multiple points in their data flow, creating persistent attack surfaces that remain exploitable across different parameter inputs.
The operational impact of CVE-2010-2041 extends beyond simple data theft or defacement, as it provides attackers with the capability to establish persistent malicious presence within the calendar application's user base. When exploited, these vulnerabilities enable attackers to perform session hijacking, steal cookies, redirect users to malicious sites, or inject additional malicious content that can propagate to other users. The vulnerability's remote nature means that attackers can exploit it without requiring physical access to the system or direct network connectivity to the target environment, making it particularly dangerous in web-based applications where users interact with the calendar from various locations. The attack surface is further expanded because the calendar application may be used by multiple users, potentially allowing a single successful exploit to compromise numerous accounts.
The exploitation of this vulnerability follows established patterns documented in the ATT&CK framework under the technique of web application attacks, specifically targeting the execution of malicious code through input injection methods. Remediation strategies should focus on implementing comprehensive input validation and output encoding mechanisms, including the adoption of proper HTML escaping for all user-supplied content before rendering. The recommended mitigation involves upgrading to PHP-Calendar version 2.0 Beta7 or later, which contains the necessary patches to address the input sanitization deficiencies. Organizations should also implement web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities. The vulnerability serves as a reminder of the critical importance of input validation and output encoding in preventing XSS attacks, aligning with security best practices outlined in various industry standards including OWASP Top Ten and NIST cybersecurity guidelines for web application security.