CVE-2018-5214 in Add Link to Facebook Plugin
Summary
by MITRE
The "Add Link to Facebook" plugin through 2.3 for WordPress has XSS via the al2fb_facebook_id parameter to wp-admin/profile.php.
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Analysis
by VulDB Data Team • 12/28/2019
The CVE-2018-5214 vulnerability affects the "Add Link to Facebook" plugin version 2.3 and earlier for WordPress platforms, representing a cross-site scripting flaw that poses significant security risks to affected websites. This vulnerability specifically targets the plugin's handling of user input through the al2fb_facebook_id parameter within the wp-admin/profile.php administrative endpoint. The issue stems from insufficient input validation and output sanitization mechanisms that fail to properly escape or filter malicious content submitted through this parameter.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script code within the al2fb_facebook_id parameter and submits it through the WordPress administrative interface. When the vulnerable plugin processes this input without proper sanitization, the malicious code gets executed in the context of other users' browsers who visit the affected administrative pages. This creates a persistent XSS attack vector that can be leveraged to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. The vulnerability exists at the application layer and requires authentication to the WordPress administrative interface, making it particularly dangerous for privileged users who maintain plugin configurations.
The operational impact of CVE-2018-5214 extends beyond simple script execution, as it can enable attackers to establish persistent access to compromised WordPress installations. When administrators visit the profile.php page with the malicious parameter, their browsers execute the injected code, potentially leading to complete account compromise and unauthorized modification of plugin settings. This vulnerability aligns with CWE-79 Cross-site Scripting flaws and can be categorized under ATT&CK technique T1566.001 for credential harvesting through phishing. The attack requires minimal user interaction beyond visiting the affected administrative page, making it particularly effective for targeting privileged WordPress users.
Mitigation strategies for this vulnerability should prioritize immediate plugin updates to versions that address the XSS flaw, as the vendor likely released a patched version resolving the input validation issues. Administrators should implement proper input sanitization practices, including the use of wp_kses() or similar escaping functions when processing user-supplied data, and ensure that all parameters passed to administrative endpoints undergo rigorous validation. Security monitoring should include detection of suspicious parameter values in administrative URLs, particularly those containing script tags or unusual character sequences. Additionally, implementing content security policies and restricting administrative access through multi-factor authentication can provide defense-in-depth measures against exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation in web applications and the potential consequences of inadequate sanitization of user-supplied data in administrative interfaces.