CVE-2017-1000038 in Relevanssi Plugin
Summary
by MITRE
WordPress plugin Relevanssi version 3.5.7.1 is vulnerable to stored XSS resulting in attacker being able to execute JavaScript on the affected site
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-1000038 affects the WordPress plugin Relevanssi version 3.5.7.1 and represents a critical stored cross-site scripting flaw that allows remote attackers to inject malicious JavaScript code into the target website. This vulnerability resides within the plugin's handling of user input data, specifically in how it processes search queries and display results. The flaw enables an attacker to store malicious scripts within the plugin's data storage mechanisms, which then execute whenever other users view the affected content, making it particularly dangerous for websites that rely on search functionality and user-generated content.
The technical implementation of this vulnerability stems from insufficient input sanitization and output escaping within the Relevanssi plugin's search processing functions. When users perform searches or when the plugin displays search results, the application fails to properly sanitize user-supplied data before storing it in the database or rendering it in web pages. This allows attackers to craft malicious payloads that contain JavaScript code, which gets stored in the plugin's database and subsequently executed in the browsers of unsuspecting users who access the affected content. The vulnerability operates as a classic stored XSS attack where the malicious code is persistently stored and executed in a victim's browser context, bypassing normal security mechanisms that protect against reflected XSS attacks.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform a wide range of malicious activities within the context of the compromised WordPress site. Attackers can leverage this vulnerability to steal user sessions, capture sensitive information, modify content, redirect users to malicious sites, or even escalate privileges within the WordPress environment. The attack vector is particularly concerning because it requires no privileged access to the WordPress installation itself, making it accessible to any attacker who can submit content or search queries to the vulnerable system. This vulnerability can be exploited through various means including search form submissions, comment fields, or any user input that gets processed by the Relevanssi plugin's search functionality, potentially affecting all users who interact with the search features of the compromised website.
Organizations affected by this vulnerability should implement immediate mitigation strategies including updating to the patched version of the Relevanssi plugin, which addresses the input sanitization issues that lead to the XSS vulnerability. The recommended remediation involves applying the official security patch released by the plugin developers, which typically includes enhanced input validation, proper output escaping, and comprehensive sanitization of user-supplied data before it is stored or rendered. Additionally, administrators should implement proper content security policies, regularly audit plugin installations for security updates, and monitor for suspicious search queries or user activities that might indicate exploitation attempts. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and maps to ATT&CK technique T1059.007 for script execution, demonstrating how the vulnerability can be leveraged for persistent access and data exfiltration within compromised WordPress environments. Organizations should also consider implementing web application firewalls and regular security scanning to detect and prevent exploitation attempts, while maintaining detailed logging of search activities to identify potential attack vectors.