CVE-2025-26763

Remediation/Mitigation Strategy for CVE-2025-26763: MetaSlider Responsive Slider Deserialization of Untrusted Data Vulnerability

This document outlines the remediation and mitigation strategy for the deserialization of untrusted data vulnerability (CVE-2025-26763) affecting the MetaSlider Responsive Slider plugin, versions up to and including 3.94.0.

1. Vulnerability Description:

  • Vulnerability: Deserialization of Untrusted Data (Object Injection)
  • Affected Software: MetaSlider Responsive Slider plugin for WordPress
  • Affected Versions: Versions up to and including 3.94.0
  • CVE ID: CVE-2025-26763
  • Description: The MetaSlider plugin is susceptible to a deserialization of untrusted data vulnerability. This occurs due to the plugin processing potentially malicious serialized data. An attacker could leverage this vulnerability to inject arbitrary PHP objects into the application, potentially leading to remote code execution (RCE). This is a critical flaw because it allows attackers to execute arbitrary code on the server, potentially compromising the entire WordPress installation and the underlying server.

2. Severity:

  • CVSS Score: 9.8 (Critical)
  • CVSS Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (Network, Low Attack Complexity, No Privileges Required, No User Interaction, Unchanged Scope, High Confidentiality Impact, High Integrity Impact, High Availability Impact)
  • Severity Level: Critical

3. Known Exploits:

  • While a specific proof-of-concept exploit may not be publicly available at the time of this writing (based on the limited information), deserialization vulnerabilities are well-understood and actively targeted by attackers. Attackers familiar with PHP object injection techniques and the MetaSlider codebase can likely develop exploits based on this vulnerability disclosure. Therefore, assuming active exploitation is prudent.

4. Remediation and Mitigation Strategy:

The primary remediation is to update the MetaSlider plugin to a version that patches the vulnerability. If updating is not immediately possible, implement mitigating controls to reduce the risk.

A. Immediate Actions (within 24-48 hours):

  • 1. Update MetaSlider Plugin: The highest priority action is to update the MetaSlider Responsive Slider plugin to the latest version as soon as a patched version is released by the developers. Monitor the official MetaSlider website (https://www.metaslider.com/) and the WordPress plugin repository for updates.
  • 2. Web Application Firewall (WAF) Rules (Mitigation): If an update is not immediately available, deploy or update WAF rules to detect and block potential deserialization attacks. Specifically, look for rules that:
    • Inspect POST requests for serialized PHP objects (identified by the O: prefix).
    • Block requests containing suspicious PHP object structures or function calls commonly used in exploitation attempts.
    • Consider using regex patterns to identify serialized data within request parameters.
  • 3. Monitor System Logs: Increase monitoring of web server and PHP error logs for suspicious activity, including:
    • Errors related to deserialization.
    • Unexpected PHP function calls.
    • Unauthorized file access or modifications.
  • 4. Disable Unused Features (Mitigation): If possible, disable any unused features or functionalities of the MetaSlider plugin that might be related to data processing or external API interactions. This reduces the attack surface.

B. Short-Term Actions (within 1 week):

  • 1. Review PHP Configuration: Ensure that allow_url_fopen is set to Off and allow_url_include is also disabled in the php.ini file. These settings prevent the inclusion of remote files, which can be exploited in conjunction with deserialization vulnerabilities.
  • 2. Implement Input Validation: Implement or enhance input validation on all data submitted to the MetaSlider plugin, even after updating. Sanitize and validate all user-provided data to prevent the injection of malicious code or serialized objects.
  • 3. Code Review (If Possible): If you have access to the MetaSlider plugin code (highly unlikely without premium/developer access), conduct a security review to identify and address any other potential vulnerabilities.
  • 4. Vulnerability Scanning: Run a vulnerability scan on the WordPress installation using a reputable security scanner (e.g., WPScan, Wordfence, Sucuri) to identify any other potential vulnerabilities in the installation, plugins, or themes.

C. Long-Term Actions (Ongoing):

  • 1. Regular Security Audits: Conduct regular security audits of the WordPress installation, including the MetaSlider plugin and all other installed components.
  • 2. Keep Software Updated: Establish a process for regularly updating WordPress core, plugins, and themes to the latest versions to address security vulnerabilities.
  • 3. Security Awareness Training: Provide security awareness training to WordPress administrators and users to educate them about common security threats and best practices.
  • 4. Secure Coding Practices: If developing custom code for WordPress or the MetaSlider plugin (or any other plugin), follow secure coding practices to prevent vulnerabilities.

5. Rollback Plan:

  • Before implementing any changes (especially plugin updates), create a complete backup of the WordPress installation (database and files).
  • If any issues arise after updating the plugin or implementing mitigation measures, revert to the backup.
  • If reverting to a backup is necessary, investigate the cause of the issue and implement a fix before re-attempting the update or mitigation. Consider staging the update/mitigation on a test environment before applying it to the production site.

6. Communication Plan:

  • Communicate the vulnerability and the remediation strategy to all stakeholders, including WordPress administrators, developers, and users.
  • Provide updates on the progress of the remediation efforts.
  • Maintain open communication channels for reporting any issues or concerns.

Disclaimer:

This remediation strategy is based on the limited information provided and general knowledge of deserialization vulnerabilities. It is essential to consult with security experts and the MetaSlider plugin developers for specific recommendations and guidance. Implementing these measures does not guarantee complete protection against attacks, but it significantly reduces the risk of exploitation. Keep monitoring for further information and guidance from security professionals.

Assigner

Date

  • Published Date: 2025-02-22 16:15:32
  • Updated Date: 2025-02-22 16:15:32

More Details

CVE-2025-26763