CVE-2012-0846 in WebCalendar
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Craig Knudsen WebCalendar 1.2.4 allows remote attackers to inject arbitrary web script or HTML via the Location variable.
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Analysis
by VulDB Data Team • 12/14/2021
The CVE-2012-0846 vulnerability represents a classic cross-site scripting flaw in the WebCalendar application version 1.2.4 developed by Craig Knudsen. This vulnerability resides in the application's handling of user input through the Location variable parameter, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of other users' browsers. The vulnerability classification aligns with CWE-79 which specifically addresses Cross-site Scripting flaws, making it a direct implementation of the well-known web application security weakness that has plagued countless applications over the years.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script code and submits it through the Location variable field. When the application processes this input without proper sanitization or encoding, the malicious script becomes embedded within the application's output and executes in the victim's browser. This type of vulnerability typically leverages the principle of insufficient input validation, where the application fails to properly validate or escape user-supplied data before incorporating it into dynamically generated web pages. The Location variable serves as the attack vector because it likely represents a field where users can enter descriptive information about calendar events or locations, making it a legitimate input point that the application does not adequately secure.
The operational impact of this vulnerability extends beyond simple script execution, creating significant security risks for organizations using the affected WebCalendar version. Attackers can leverage this flaw to steal session cookies, perform unauthorized actions on behalf of users, redirect victims to malicious sites, or even deface the calendar application itself. The remote nature of the attack means that exploitation does not require physical access to the system or any special privileges, making it particularly dangerous as it can be exploited from anywhere on the internet. This vulnerability particularly affects web applications that do not properly implement input validation and output encoding, and the impact is amplified when the calendar application is used by multiple users who may have varying levels of access or sensitive information stored within the system.
Mitigation strategies for CVE-2012-0846 should focus on implementing proper input validation and output encoding mechanisms throughout the application's codebase. The most effective immediate fix involves sanitizing all user input through proper encoding before rendering it in web pages, specifically implementing HTML entity encoding for the Location variable and similar input fields. Organizations should also consider implementing Content Security Policy headers to limit script execution capabilities and prevent unauthorized code injection. The vulnerability demonstrates the critical importance of following secure coding practices as outlined in the OWASP Top Ten and the principle of defense in depth. Additionally, regular security assessments and input validation testing should be conducted to identify similar vulnerabilities in other application components, as this type of flaw often indicates broader security gaps in the application's architecture. The remediation process should include updating to a patched version of WebCalendar if available, or implementing proper input sanitization mechanisms if upgrading is not immediately possible, thereby addressing the root cause of the vulnerability through proper data handling practices.