CVE-2019-18347 in DAViCal
Summary
by MITRE
A stored XSS issue was discovered in DAViCal through 1.1.8. It does not adequately sanitize output of various fields that can be set by unprivileged users, making it possible for JavaScript stored in those fields to be executed by another (possibly privileged) user. Affected database fields include Username, Display Name, and Email.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability CVE-2019-18347 represents a critical stored cross-site scripting flaw in the DAViCal calendar and scheduling server version 1.1.8 and earlier. This vulnerability resides in the application's insufficient input sanitization mechanisms that fail to properly validate and escape user-supplied data before storing it in the database. The flaw specifically affects three critical database fields including Username, Display Name, and Email, which are commonly populated by unprivileged users within collaborative environments. The vulnerability is classified as a CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security that allows malicious code injection.
The technical exploitation of this vulnerability occurs when an attacker with limited privileges creates or modifies user accounts with malicious JavaScript code embedded within the affected fields. When other users, potentially including administrators or privileged accounts, view the compromised user information through the DAViCal interface, the stored JavaScript code executes in their browser context. This creates a persistent threat vector where the malicious payload can be delivered to any user who accesses the vulnerable data, making it particularly dangerous in collaborative environments where multiple users interact with shared calendar and contact information. The vulnerability demonstrates a failure in the principle of least privilege and proper output encoding, which are core security controls recommended by the OWASP Top Ten and NIST Cybersecurity Framework.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to escalate privileges, steal session cookies, perform unauthorized actions on behalf of victims, or redirect users to malicious websites. In a calendar server environment, this could allow attackers to access sensitive scheduling information, modify calendar entries, or compromise the entire user authentication system. The vulnerability affects not just individual users but potentially the entire organization's collaborative infrastructure, as calendar servers typically contain sensitive personal and business information. This aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, and demonstrates how web application flaws can be leveraged for broader compromise. The persistent nature of stored XSS makes it particularly challenging to detect and remediate, as the malicious code remains active until explicitly removed from the database.
Organizations should implement immediate mitigations including upgrading to DAViCal version 1.1.9 or later where the vulnerability has been patched, implementing comprehensive input validation and output encoding for all user-supplied data, and conducting thorough security reviews of all database fields that accept user input. Additional protective measures include implementing Content Security Policy headers, regular security scanning of web applications, and user education regarding the dangers of clicking on suspicious links or entering untrusted data in collaborative environments. The vulnerability serves as a reminder of the critical importance of proper input sanitization and output encoding in web applications, as outlined in the OWASP Secure Coding Practices and the ISO/IEC 27001 information security management standards.