CVE-2019-6261 in Joomla
Summary
by MITRE
An issue was discovered in Joomla! before 3.9.2. Inadequate escaping in com_contact leads to a stored XSS vulnerability.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/31/2020
The vulnerability identified as CVE-2019-6261 represents a critical stored cross-site scripting flaw within the Joomla websites. The vulnerability stems from insufficient output escaping mechanisms that fail to properly sanitize user-supplied data before rendering it within web pages. Attackers can exploit this weakness by submitting malicious scripts through contact form fields or other input points within the com_contact component, which then get stored in the database and executed whenever the affected page is accessed by other users. The stored nature of this vulnerability makes it particularly dangerous as the malicious code persists and can affect multiple users over time without requiring repeated exploitation attempts.
The technical implementation of this vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws as weaknesses in web applications where untrusted data is improperly escaped or filtered before being rendered in web pages. This specific flaw demonstrates a failure in input validation and output encoding practices that should follow established security protocols. The attack vector involves a malicious actor submitting crafted payloads through the contact form interface, which are then stored in the Joomla! database and executed in the context of other users' browsers when they view the affected contact information. The vulnerability operates at the application layer and requires no special privileges or authentication to exploit, making it accessible to anyone with access to the vulnerable website's contact functionality.
The operational impact of CVE-2019-6261 extends beyond simple script execution as it provides attackers with the capability to perform session hijacking, steal user credentials, redirect victims to malicious websites, or perform actions on behalf of authenticated users. The stored nature of the vulnerability means that even if the initial attacker's session ends, the malicious code continues to affect all subsequent users who access the compromised contact information. This creates a persistent threat that can remain undetected for extended periods, potentially allowing attackers to harvest sensitive data, manipulate website content, or establish backdoors within the Joomla! installation. The vulnerability affects all users who have access to the affected contact forms, including website administrators, making it particularly concerning for sites with multiple user roles and permissions.
Organizations affected by this vulnerability should immediately upgrade to Joomla! version 3.9.2 or later where the escaping mechanisms have been properly implemented to address the XSS flaw. The mitigation strategy should include comprehensive input validation, proper output encoding, and regular security auditing of all web application components. Security teams should also implement web application firewalls to detect and block suspicious payloads, conduct thorough penetration testing to identify similar vulnerabilities in other components, and establish monitoring procedures to detect unauthorized modifications to contact forms or related data. Additionally, administrators should review user permissions and access controls to limit who can submit data through contact forms, while implementing proper logging mechanisms to track all submissions and identify potential exploitation attempts. The vulnerability highlights the critical importance of maintaining up-to-date software versions and following secure coding practices to prevent such persistent security flaws from compromising web applications and their users' data.