CVE-2017-13138 in Bridge Theme
Summary
by MITRE
DOM based Cross-site scripting (XSS) vulnerability in the Bridge theme before 11.2 for WordPress allows remote attackers to inject arbitrary JavaScript.
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Analysis
by VulDB Data Team • 11/09/2019
The vulnerability identified as CVE-2017-13138 represents a critical DOM-based cross-site scripting flaw within the Bridge theme for WordPress platforms prior to version 11.2. This security weakness specifically affects the theme's handling of user input within the Document Object Model, creating an avenue for remote attackers to execute malicious JavaScript code in the context of affected websites. The vulnerability stems from inadequate sanitization and validation of input parameters that are processed through the theme's JavaScript components, allowing attackers to inject malicious payloads that can persist and execute in users' browsers when they navigate to affected pages.
The technical implementation of this vulnerability involves the theme's improper handling of URL parameters and user-supplied data within its JavaScript execution context. When the Bridge theme processes certain input values through DOM manipulation functions, it fails to properly sanitize or escape these inputs before incorporating them into dynamic JavaScript code execution. This creates a condition where attacker-controlled data can be interpreted as executable code rather than benign input, effectively bypassing traditional server-side input validation mechanisms. The vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws, and more precisely aligns with CWE-80 which deals with improper neutralization of script references in a DOM-based context. The attack vector operates entirely through client-side JavaScript execution without requiring direct server-side code injection, making it particularly insidious as it can be exploited through various means including social engineering, malicious links, or compromised advertisements.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with the capability to establish persistent malicious presence on compromised websites. Once exploited, the injected JavaScript can perform a wide range of malicious activities including but not limited to session hijacking, credential theft, redirection to malicious sites, data exfiltration, and even the installation of additional malware. The remote nature of the attack means that exploitation can occur from any location without requiring physical access to the target system or network. Attackers can craft malicious URLs that, when clicked by unsuspecting users, will execute the injected JavaScript code in the victim's browser context, potentially compromising user sessions and gaining unauthorized access to sensitive information. This vulnerability also aligns with several tactics in the MITRE ATT&CK framework under the T1059.007 technique for "Command and Scripting Interpreter: JavaScript" and T1566.001 for "Phishing: Spearphishing Attachment" when considering how attackers might leverage this vulnerability through malicious email campaigns.
Organizations affected by this vulnerability should immediately implement comprehensive mitigation strategies including the immediate upgrade to Bridge theme version 11.2 or later, which contains the necessary patches to address the DOM-based XSS flaw. Additionally, administrators should implement proper input validation and output encoding mechanisms within their WordPress installations, particularly focusing on JavaScript contexts where user-supplied data is processed. The implementation of Content Security Policy headers can provide an additional layer of protection by restricting the sources from which scripts can be executed, thereby limiting the impact of potential exploitation attempts. Regular security auditing of WordPress themes and plugins should be conducted to identify similar vulnerabilities, and automated monitoring systems should be deployed to detect unauthorized modifications to website content. The vulnerability also underscores the importance of keeping all WordPress components updated, as the patch for this specific issue was included in the theme's version 11.2 release, demonstrating the critical nature of timely security updates in maintaining robust web application defenses.