CVE-2017-17093 in WordPress
Summary
by MITRE
wp-includes/general-template.php in WordPress before 4.9.1 does not properly restrict the lang attribute of an HTML element, which might allow attackers to conduct XSS attacks via the language setting of a site.
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Analysis
by VulDB Data Team • 01/16/2023
The vulnerability identified as CVE-2017-17093 resides within the WordPress content management system and specifically affects versions prior to 4.9.1. This issue is classified as a cross-site scripting vulnerability that stems from insufficient input validation and sanitization within the general-template.php file. The flaw occurs when WordPress processes the language attribute of HTML elements, failing to properly restrict or escape the lang attribute value that can be manipulated by attackers. This vulnerability represents a critical security risk as it allows malicious actors to inject malicious scripts into web pages viewed by other users, potentially compromising user sessions and executing unauthorized actions on behalf of victims.
The technical implementation of this vulnerability involves the wp-includes/general-template.php file which handles the generation of HTML output for WordPress sites. When WordPress renders language-related attributes in HTML elements, the system does not adequately sanitize the lang parameter that can be set through site configuration or user input. This lack of proper sanitization creates an avenue for attackers to inject malicious JavaScript code through the language setting, which then executes in the context of other users' browsers when they visit affected pages. The vulnerability is particularly dangerous because it leverages legitimate WordPress functionality to deliver malicious payloads, making it difficult to detect and block through traditional security measures.
The operational impact of CVE-2017-17093 extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data theft, and privilege escalation. An attacker who successfully exploits this vulnerability can manipulate the language settings of a WordPress site to inject persistent XSS payloads that will affect all visitors to the site. This vulnerability aligns with CWE-79 which identifies cross-site scripting flaws, and represents a specific instance of CWE-79: Improper Neutralization of Input During Web Page Generation. The attack vector is particularly concerning as it requires minimal privileges to exploit and can be executed through legitimate administrative interfaces or by manipulating configuration parameters.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1059.007 for Scripting and T1566 for Phishing, as attackers can leverage the XSS capability to deliver malicious payloads or redirect users to compromised sites. The vulnerability affects WordPress installations across all supported versions prior to 4.9.1, making it a widespread concern for organizations using the platform. The exploitation requires minimal technical skill and can be automated, making it attractive to threat actors seeking to compromise large numbers of WordPress sites. Organizations should consider this vulnerability as part of their broader security posture assessment, particularly those running legacy WordPress installations or those that have not implemented proper input validation mechanisms.
The remediation strategy for CVE-2017-17093 involves upgrading to WordPress version 4.9.1 or later, which includes proper sanitization of the lang attribute in the general-template.php file. Additionally, organizations should implement input validation measures at multiple layers including web application firewalls, content security policies, and regular security audits of WordPress installations. Security teams should also consider implementing monitoring for suspicious language setting modifications and maintain up-to-date threat intelligence to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input sanitization in web applications and highlights the need for continuous security testing and patch management processes to protect against similar issues in the future.