CVE-2024-13636 in Brooklyn Plugin
Summary
by MITRE • 02/18/2025
The Brooklyn theme for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 4.9.9.2 via deserialization of untrusted input in the ot_decode function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP Object. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/25/2025
The vulnerability in the Brooklyn theme for WordPress represents a critical security flaw that exploits PHP Object Injection through improper input validation during deserialization processes. This weakness affects all versions up to and including 4.9.9.2, creating a significant risk for WordPress installations that utilize this theme. The specific point of exploitation occurs within the ot_decode function where untrusted input undergoes deserialization without adequate sanitization measures, allowing maliciously crafted data to be transformed into executable PHP objects.
The technical nature of this vulnerability aligns with CWE-502 which categorizes insecure deserialization as a serious weakness that can lead to arbitrary code execution. The attack vector requires authenticated access at the Subscriber level or higher, making it particularly concerning for environments where user privileges are not properly managed or restricted. This authentication requirement does not diminish the severity since subscribers in WordPress often have access to various theme customization options and administrative functions that could be leveraged for further exploitation.
The operational impact of this vulnerability extends beyond simple privilege escalation as it creates a potential pathway for attackers to establish persistent access or cause significant damage to affected systems. While no known POP (Points of Priority) chain exists within the vulnerable Brooklyn theme itself, the absence of such chains does not eliminate the threat entirely. Instead, it creates a scenario where the vulnerability becomes potentially exploitable only when combined with other plugins or themes that contain active POP chains, transforming what might initially appear as a limited vector into a more dangerous attack surface.
This dependency on additional software components for exploitation actually demonstrates how security vulnerabilities can compound in complex ecosystems like WordPress, where multiple themes and plugins interact. The vulnerability's potential impact ranges from arbitrary file deletion to sensitive data retrieval and remote code execution depending entirely on what other components are present in the target environment. Security practitioners should consider this vulnerability within the broader context of supply chain attacks where a seemingly minor flaw in one component can become weaponized through combinations with other vulnerable software.
Mitigation strategies must focus on both immediate remediation through theme updates and comprehensive security monitoring to identify potentially malicious activity. Organizations should implement strict access controls to prevent unauthorized user account creation and ensure that all WordPress components are kept current with security patches. The vulnerability also highlights the importance of regular security audits that examine not just individual components but their interactions within the complete system landscape, which aligns with ATT&CK technique T1548.003 for privilege escalation through application access tokens and other authentication mechanisms.
The broader implications of this vulnerability extend to WordPress security best practices, emphasizing the need for robust input validation and secure coding practices throughout the development lifecycle. Security teams should consider implementing web application firewalls that can detect and block suspicious deserialization attempts, while also maintaining detailed monitoring of user activities that could indicate exploitation attempts. Additionally, organizations should develop incident response procedures specifically tailored to address such vulnerabilities that require multiple components to be exploited effectively, ensuring rapid detection and remediation when such attacks occur in production environments.