CVE-2017-10840 in Webcalendar
Summary
by MITRE
Cross-site scripting vulnerability in WebCalendar 1.2.7 and earlier allows an attacker to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-10840 represents a critical cross-site scripting flaw within WebCalendar version 1.2.7 and earlier releases, demonstrating a fundamental weakness in input validation and output encoding mechanisms. This vulnerability falls under the category of CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly sanitize user-supplied data before incorporating it into web pages. The issue manifests when the application fails to adequately filter or escape user input that gets rendered back to clients, creating an avenue for malicious script execution. The unspecified vectors suggest that the vulnerability could potentially be exploited through multiple entry points within the web application's interface, including but not limited to form fields, URL parameters, or user profile data.
The technical exploitation of this vulnerability enables attackers to inject arbitrary web scripts or HTML content into the web application's output, potentially leading to unauthorized actions performed on behalf of legitimate users. When a victim visits a maliciously crafted page or interacts with compromised content, the injected scripts execute within the victim's browser context, potentially compromising session cookies, redirecting users to phishing sites, or extracting sensitive information. The impact extends beyond simple script injection as it can facilitate more sophisticated attacks including session hijacking, credential theft, and data exfiltration. This vulnerability directly aligns with ATT&CK technique T1059.001 - Command and Scripting Interpreter: PowerShell, as attackers can leverage the XSS payload to execute malicious commands or scripts within the victim's browser environment.
The operational impact of CVE-2017-10840 is significant for organizations utilizing affected WebCalendar versions, as it undermines the integrity and security of the web application's user interface. Attackers can exploit this vulnerability to manipulate calendar events, modify user permissions, or gain unauthorized access to calendar data, potentially exposing sensitive organizational information. The vulnerability's persistence in the application's codebase indicates a lack of proper security testing and input validation procedures during the development lifecycle. Organizations relying on WebCalendar for scheduling and calendar management functions face potential business disruption, data breaches, and compliance violations. The vulnerability's exploitation requires minimal technical skill, making it particularly dangerous as it can be leveraged by threat actors with varying levels of expertise.
Mitigation strategies for CVE-2017-10840 primarily involve immediate patching of the WebCalendar application to a version that addresses the XSS vulnerability, typically through the implementation of proper input sanitization and output encoding mechanisms. Organizations should implement comprehensive input validation that filters or escapes special characters commonly used in XSS attacks, including angle brackets, quotes, and script tags. The application should employ context-specific output encoding to ensure that user-supplied data is properly escaped when rendered in different contexts such as HTML, JavaScript, and URL parameters. Additionally, organizations should deploy web application firewalls and security monitoring solutions to detect and prevent exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications, while implementing proper security training for developers to prevent future occurrences of such flaws. The remediation process should also include thorough testing to ensure that the patch does not introduce regressions in application functionality while maintaining the security posture against similar attack vectors.