CVE-2024-8353: GiveWP Plugin RCE Vulnerability

CVE-2024-8353 Overview

CVE-2024-8353 is a critical PHP Object Injection vulnerability affecting the GiveWP – Donation Plugin and Fundraising Platform for WordPress. This popular donation and fundraising plugin contains insecure deserialization flaws in multiple parameters including give_title and card_address, allowing unauthenticated attackers to inject malicious PHP objects. When combined with an existing Property Oriented Programming (POP) chain, this vulnerability enables arbitrary file deletion and remote code execution on affected WordPress installations.

This vulnerability is particularly concerning as it represents a bypass of the fix implemented for CVE-2024-5932. Researchers discovered that the presence of stripslashes_deep on the user_info parameter allows attackers to bypass the is_serialized security check, effectively circumventing the previous mitigation efforts.

Critical Impact

Unauthenticated attackers can achieve remote code execution and delete arbitrary files on WordPress sites running vulnerable versions of GiveWP, potentially leading to complete site compromise.

Affected Products

• GiveWP – Donation Plugin and Fundraising Platform versions up to and including 3.16.1
• WordPress sites using vulnerable GiveWP plugin installations
• All WordPress environments running GiveWP versions prior to 3.16.2

Discovery Timeline

• 2024-09-28 - CVE-2024-8353 published to NVD
• 2024-10-01 - Last updated in NVD database

Technical Details for CVE-2024-8353

Vulnerability Analysis

This PHP Object Injection vulnerability exists in the donation processing functionality of the GiveWP plugin. The core issue stems from improper handling of user-supplied input during the deserialization process. Multiple parameters within the donation form, specifically give_title and card_address, accept serialized PHP data without adequate validation.

The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data), a well-known class of vulnerabilities that occur when applications deserialize data from untrusted sources without proper verification. In this case, the attack surface is network-accessible and requires no authentication, making it particularly dangerous for public-facing WordPress sites.

What makes this vulnerability notable is its relationship to CVE-2024-5932. While that previous vulnerability was addressed, the fix was incomplete. The stripslashes_deep function applied to the user_info parameter creates a condition where specially crafted payloads can bypass the is_serialized check that was implemented as a security measure.

Root Cause

The root cause of CVE-2024-8353 lies in insufficient input validation and an incomplete security fix from the previous vulnerability (CVE-2024-5932). The stripslashes_deep function, which removes escape characters from user input, processes the data before the is_serialized security check is performed. This processing order allows attackers to craft serialized payloads with strategically placed escape characters that are stripped, resulting in valid serialized objects that bypass the deserialization detection mechanism.

The plugin fails to properly sanitize or validate serialized data in donation form parameters before passing them to PHP's deserialization functions. Combined with the presence of exploitable POP (Property Oriented Programming) chains in the WordPress ecosystem, this allows attackers to execute arbitrary code on the server.

Attack Vector

The attack vector for CVE-2024-8353 is network-based and requires no authentication or user interaction. Attackers can exploit this vulnerability by:

1. Crafting a malicious serialized PHP object payload with escape characters designed to bypass the is_serialized check after stripslashes_deep processing
2. Submitting the payload through donation form parameters such as give_title or card_address
3. The server processes the input through stripslashes_deep, removing escape characters and creating a valid serialized object
4. The malformed payload bypasses the is_serialized security check
5. PHP deserializes the malicious object, triggering the POP chain
6. Depending on the POP chain used, attackers can delete arbitrary files or achieve remote code execution

The vulnerability is exploitable remotely without any prior access to the WordPress site, making any publicly accessible installation running a vulnerable version of GiveWP a potential target.

Detection Methods for CVE-2024-8353

Indicators of Compromise

• Unexpected serialized data patterns in web server access logs containing give_title or card_address parameters
• Unusual POST requests to donation processing endpoints with encoded or obfuscated payloads
• Deleted or modified files on the WordPress installation without administrator action
• Evidence of unauthorized PHP code execution in server logs
• New or modified files in WordPress directories, particularly in writable locations

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in form submissions
• Monitor donation form submissions for anomalous payload sizes or character patterns indicative of serialization attacks
• Deploy file integrity monitoring to detect unauthorized file deletions or modifications
• Review PHP error logs for deserialization-related errors or unexpected object instantiation

Monitoring Recommendations

• Enable verbose logging for the GiveWP plugin and monitor for suspicious donation form activity
• Configure alerts for any access to donation processing endpoints from unusual geographic locations or IP ranges
• Implement real-time file system monitoring on critical WordPress directories
• Set up notifications for any changes to WordPress core files, themes, or plugin files

How to Mitigate CVE-2024-8353

Immediate Actions Required

• Update the GiveWP plugin to version 3.16.2 or later immediately
• Audit WordPress installations for signs of compromise, including unexpected file changes or new administrator accounts
• Review server access logs for evidence of exploitation attempts targeting donation form endpoints
• Consider temporarily disabling the GiveWP plugin if immediate patching is not possible

Patch Information

The GiveWP development team addressed this vulnerability in two phases. Version 3.16.1 contained the initial fix that addressed most of the vulnerability, while version 3.16.2 added additional hardening measures to fully remediate the issue. Organizations should update to version 3.16.2 or later to ensure complete protection.

Detailed patch information is available through the official WordPress plugin repository:

• WordPress Admin Actions Changeset
• WordPress Donation Process Changeset
• WordPress Utils Changeset
• WordPress Donation Process Update (3.16.2)

Additional vulnerability details are available in the Wordfence Vulnerability Report.

Workarounds

• Deploy a Web Application Firewall (WAF) with rules to block serialized PHP object patterns in POST requests to GiveWP endpoints
• Implement strict input validation at the web server level to filter potentially malicious serialized data
• Restrict access to donation form endpoints using IP allowlisting if your user base is geographically limited
• Consider using a security plugin that can detect and block PHP object injection attempts

# Example WAF rule pattern to detect PHP serialization attacks
# Add to ModSecurity or similar WAF configuration
SecRule ARGS "@rx O:\d+:\"" "id:1001,phase:2,deny,status:403,msg:'Potential PHP Object Injection'"
SecRule ARGS "@rx a:\d+:{" "id:1002,phase:2,deny,status:403,msg:'Potential PHP Array Injection'"