CVE-2017-18598 in Qards Plugin
Summary
by MITRE
The Qards plugin through 2017-10-11 for WordPress has XSS via a remote document specified in the url parameter to html2canvasproxy.php.
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Analysis
by VulDB Data Team • 12/19/2023
The vulnerability identified as CVE-2017-18598 affects the Qards plugin version 2017-10-11 and earlier for the WordPress content management system. This represents a cross-site scripting vulnerability that specifically targets the html2canvasproxy.php endpoint within the plugin's functionality. The issue arises from insufficient input validation and sanitization of user-supplied data, creating an avenue for malicious actors to inject arbitrary web scripts into the plugin's processing pipeline. The vulnerability is particularly concerning as it allows remote code execution through the manipulation of the url parameter, potentially enabling attackers to compromise the WordPress installation and gain unauthorized access to sensitive data or system resources.
The technical flaw manifests in the improper handling of the url parameter within the html2canvasproxy.php script, which acts as a proxy for converting HTML content to canvas elements. When the plugin receives a request containing a malicious url parameter, it fails to adequately sanitize or validate the input before processing it through the html2canvas conversion function. This vulnerability is classified under CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications. The weakness exists in the plugin's lack of proper output encoding and input validation mechanisms, allowing attackers to inject malicious JavaScript code that gets executed in the context of legitimate users' browsers. The vulnerability can be exploited through various attack vectors including social engineering techniques where users are tricked into clicking malicious links or through automated scanning tools that identify and exploit such insecure parameter handling.
The operational impact of this vulnerability extends beyond simple script injection, as it can lead to complete compromise of the WordPress installation and potentially the underlying server infrastructure. Attackers can leverage this vulnerability to perform session hijacking, steal administrative credentials, deface websites, inject malicious advertisements, or redirect users to phishing sites. The vulnerability affects all WordPress installations running the vulnerable Qards plugin version, making it particularly dangerous as it targets a widely used plugin with potentially thousands of installations. The remote nature of the exploit means that attackers do not require physical access to the system or local network privileges, enabling them to conduct attacks from anywhere on the internet. This vulnerability aligns with ATT&CK technique T1566, which covers phishing attacks that can be facilitated through web-based exploits like this XSS vulnerability, and T1059 which covers command and scripting interpreter techniques that attackers can use to execute malicious code.
Mitigation strategies for this vulnerability should include immediate patching of the Qards plugin to the latest version that addresses the XSS flaw. System administrators should also implement input validation and output encoding measures at the web application level, ensuring that all user-supplied parameters are properly sanitized before processing. The implementation of Content Security Policy headers can provide additional protection against XSS attacks by restricting the sources from which scripts can be loaded and executed. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other plugins and themes. Organizations should also consider implementing web application firewalls to detect and block malicious requests targeting known XSS patterns. The vulnerability highlights the importance of keeping all WordPress plugins and themes updated, as outdated components often contain unpatched security flaws that attackers actively exploit in the wild. Additionally, security monitoring should be enhanced to detect unusual traffic patterns or suspicious requests that may indicate exploitation attempts against the html2canvasproxy.php endpoint.