CVE-2017-1000225 in Relevanssi Premium Plugin
Summary
by MITRE
Reflected XSS in Relevanssi Premium version 1.14.8 when using relevanssi_didyoumean() could allow unauthenticated attacker to do almost anything an admin can
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Analysis
by VulDB Data Team • 12/08/2019
The vulnerability identified as CVE-2017-1000225 represents a critical reflected cross-site scripting flaw within the Relevanssi Premium WordPress plugin version 1.14.8. This security weakness specifically manifests when the relevanssi_didyoumean() function is invoked, creating a pathway for unauthenticated attackers to execute malicious scripts within the context of administrative sessions. The vulnerability stems from insufficient input validation and output sanitization mechanisms that fail to properly escape user-supplied data before incorporating it into dynamic web responses.
The technical exploitation of this vulnerability occurs through the manipulation of query parameters that are processed by the relevanssi_didyoumean() function, which is commonly used for spell-checking and search suggestion features. When an attacker crafts malicious input and injects it into search queries or other user-controllable parameters, the vulnerable plugin fails to adequately sanitize this data before rendering it in the browser. This reflected XSS condition allows attackers to inject malicious JavaScript code that executes in the context of admin sessions, potentially enabling full administrative control over affected WordPress installations.
The operational impact of this vulnerability extends far beyond simple script execution, as it provides attackers with the capability to perform administrative actions that are typically restricted to authorized users. An attacker could leverage this vulnerability to modify plugin settings, access sensitive data, manipulate content, install malicious plugins, or even completely compromise the WordPress installation. The severity is amplified by the fact that no authentication is required for exploitation, making it particularly dangerous in environments where the plugin is widely deployed across multiple sites or where administrative privileges are accessible through other means.
This vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in web applications, and demonstrates characteristics consistent with the attack patterns documented in the MITRE ATT&CK framework under the technique T1059.1001 for command and scripting interpreter. The attack surface is particularly concerning given that WordPress plugins often have elevated privileges and access to sensitive system functions. Organizations using affected versions of Relevanssi Premium should immediately implement mitigations including input validation, output encoding, and access control restrictions. The recommended remediation involves updating to a patched version of the plugin, implementing web application firewalls, and conducting thorough security audits of plugin configurations to ensure that only authorized users can access administrative functions.
The broader implications of this vulnerability highlight the critical importance of proper input validation and output sanitization in web applications, particularly those handling user-generated content. This flaw demonstrates how seemingly benign plugin functionality can become a gateway for complete system compromise, emphasizing the need for comprehensive security testing of third-party components and regular security updates. The vulnerability serves as a reminder that even plugins designed for search enhancement can pose significant risks when not properly secured against injection attacks. Organizations should implement robust security monitoring, maintain updated security patches, and conduct regular vulnerability assessments to prevent similar issues from compromising their web infrastructure.