CVE-2020-15696 in Joomla
Summary
by MITRE
An issue was discovered in Joomla! through 3.9.19. Lack of input filtering and escaping allows XSS attacks in mod_random_image.
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Analysis
by VulDB Data Team • 07/16/2020
The vulnerability identified as CVE-2020-15696 represents a critical cross-site scripting weakness within the Joomla! content management system affecting versions through 3.9.19. This flaw resides specifically within the mod_random_image module, which is a widely used component for displaying random images on websites. The vulnerability stems from insufficient input validation and output escaping mechanisms that fail to properly sanitize user-supplied data before incorporating it into web page responses. Attackers can exploit this weakness by injecting malicious scripts into parameters that are processed by the module, potentially leading to unauthorized access, session hijacking, or data theft. The issue demonstrates a classic lack of proper input sanitization that violates fundamental security principles outlined in the OWASP Top Ten and CWE-79 which specifically addresses cross-site scripting vulnerabilities. The module's failure to properly escape output creates an environment where malicious payloads can be executed in the context of other users' browsers, making it particularly dangerous for websites that rely on user-generated content or dynamic parameters.
The technical exploitation of this vulnerability occurs when an attacker manipulates input parameters that are processed by the mod_random_image module without adequate filtering. The vulnerability allows attackers to inject JavaScript code or other malicious payloads that will execute in the browser of unsuspecting users who visit pages containing the compromised module. This type of attack typically involves crafting malicious URLs or form submissions that contain script tags or other XSS vectors. The impact extends beyond simple script execution as it can enable more sophisticated attacks including credential theft through cookie manipulation, redirection to malicious sites, or even privilege escalation if the affected user has administrative privileges. The vulnerability's persistence in the codebase for an extended period highlights the importance of regular security audits and the implementation of secure coding practices that prevent such issues from emerging in the first place. According to ATT&CK framework, this vulnerability maps to T1059.007 for the execution of malicious code through scripting and T1566 for the initial access vector through web application attacks.
Organizations utilizing Joomla development team, which typically include enhanced input validation and output escaping mechanisms. Additionally, administrators should consider implementing web application firewalls that can detect and block common XSS attack patterns targeting this specific vulnerability. Input validation should be strengthened at multiple levels including server-side validation and client-side sanitization to ensure that all user-supplied data is properly filtered before being processed by the application. Security monitoring should be enhanced to detect unusual patterns in module usage or unexpected parameter values that might indicate exploitation attempts. The vulnerability also underscores the importance of maintaining up-to-date security practices and following the principle of least privilege when configuring web applications, ensuring that modules have minimal necessary permissions and access rights. Organizations should also conduct regular security assessments and penetration testing to identify similar vulnerabilities across their entire web application portfolio, as this particular weakness serves as a reminder of how easily input validation failures can create exploitable conditions in widely deployed software components.