CVE-2017-14724 in WordPress
Summary
by MITRE
Before version 4.8.2, WordPress was vulnerable to cross-site scripting in oEmbed discovery.
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Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-14724 represents a critical cross-site scripting flaw in WordPress versions prior to 4.8.2, specifically affecting the oEmbed discovery mechanism. This vulnerability resides within the core WordPress framework's handling of embedded content from external sources, where the system fails to properly sanitize user input during the oEmbed discovery process. The issue allows malicious actors to inject malicious scripts into WordPress sites through crafted oEmbed requests, potentially compromising user sessions and enabling unauthorized access to sensitive data. The vulnerability stems from insufficient input validation and output sanitization within the oEmbed functionality that WordPress uses to display embedded content from third-party services such as YouTube, Vimeo, and other supported platforms.
The technical exploitation of this vulnerability occurs when WordPress processes oEmbed discovery requests from external domains without adequate sanitization of the embedded content parameters. Attackers can craft malicious URLs or content that, when processed by the vulnerable WordPress version, executes arbitrary JavaScript code within the context of the victim's browser. This occurs because the oEmbed discovery mechanism in older WordPress versions does not properly escape or validate data retrieved from external sources before displaying it on the page. The flaw specifically affects the way WordPress handles the discovery of oEmbed endpoints and processes the responses, creating an injection vector for cross-site scripting attacks that can persist across user sessions and potentially escalate to full account compromise.
The operational impact of CVE-2017-14724 extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal cookies, modify content, and potentially gain administrative privileges if users with elevated permissions interact with the malicious content. This vulnerability affects WordPress installations that rely on oEmbed functionality for displaying embedded media, which represents a significant portion of WordPress sites since oEmbed is a core feature for embedding content from various platforms. The attack surface is particularly concerning because oEmbed discovery occurs automatically when WordPress encounters links to supported external services, making it difficult for site administrators to prevent without updating their WordPress installations. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and can be mapped to ATT&CK technique T1059.007 for script injection attacks.
Mitigation strategies for CVE-2017-14724 require immediate implementation of the WordPress 4.8.2 security update, which includes proper sanitization of oEmbed discovery responses and enhanced validation of external content. Organizations should also implement additional security measures such as content security policies that restrict script execution, regular monitoring of oEmbed endpoints for suspicious activity, and network-level filtering to block known malicious domains. Site administrators should conduct thorough security audits to identify any custom implementations that might be vulnerable to similar injection vectors, while also ensuring that all plugins and themes are updated to maintain overall security posture. The vulnerability demonstrates the importance of maintaining current WordPress installations and following security best practices for content management systems, as oEmbed functionality represents a common attack vector that requires careful input validation and output sanitization to prevent exploitation.