CVE-2023-5239 in Security & Malware Scan Plugin
Summary
by MITRE • 11/27/2023
The Security & Malware scan by CleanTalk WordPress plugin before 2.121 retrieves client IP addresses from potentially untrusted headers, allowing an attacker to manipulate its value. This may be used to bypass bruteforce protection.
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Analysis
by VulDB Data Team • 12/17/2023
The vulnerability identified as CVE-2023-5239 resides within the CleanTalk WordPress plugin, specifically affecting versions prior to 2.121. This security flaw involves the plugin's security and malware scanning functionality that incorrectly processes client IP address information. The issue stems from the plugin's reliance on HTTP headers that can be easily manipulated by malicious actors, creating a vector for bypassing critical security controls. The vulnerability represents a significant concern for WordPress site administrators who depend on the plugin for protecting their installations against various threats. The improper handling of IP address data creates a scenario where an attacker can spoof their true location and potentially circumvent protection mechanisms designed to prevent unauthorized access attempts.
The technical flaw manifests in the plugin's failure to properly validate or sanitize IP address values obtained from HTTP headers. When the plugin processes incoming requests, it extracts IP information from headers such as X-Forwarded-For, X-Real-IP, or similar fields that are commonly used to determine the original client IP address when requests pass through proxies or load balancers. However, these headers are inherently unreliable as they can be set by any client making the request, making them susceptible to manipulation. The vulnerability specifically allows attackers to inject false IP addresses that the plugin will accept as legitimate, effectively bypassing the intended security controls that rely on accurate IP identification. This behavior directly violates security best practices for input validation and trust assumptions in network communications.
The operational impact of this vulnerability extends beyond simple IP address spoofing to encompass broader security implications for brute force protection mechanisms. When attackers can manipulate the reported IP address, they can circumvent rate limiting and brute force protection features that are fundamental to preventing unauthorized access attempts. This creates a scenario where malicious actors can perform unlimited login attempts from what the system believes to be different IP addresses, effectively nullifying the protection that the plugin provides. The vulnerability undermines the integrity of the security monitoring system by allowing attackers to appear as legitimate users from various IP addresses, potentially evading detection and making their activities harder to trace. This weakness particularly affects WordPress installations that rely heavily on the CleanTalk plugin for security monitoring and automated threat response.
Mitigation strategies for CVE-2023-5239 primarily focus on updating to the patched version 2.121 or later of the CleanTalk plugin, which addresses the improper IP address handling through proper validation and sanitization of header values. Administrators should implement additional security measures such as configuring web servers to strip or properly validate forwarded headers, implementing more robust authentication mechanisms with multi-factor authentication, and deploying additional monitoring solutions that can detect anomalous login patterns regardless of reported IP addresses. Network-level protections including firewalls and intrusion detection systems should be configured to monitor for suspicious login behavior and implement more sophisticated rate limiting that considers multiple factors beyond simple IP address tracking. The vulnerability aligns with CWE-20, which addresses improper input validation, and represents a specific implementation of the broader ATT&CK technique T1110, which involves password guessing and credential brute force attacks. Organizations should also consider implementing security monitoring that can detect and alert on potential exploitation attempts, particularly focusing on unusual login patterns and multiple authentication failures from seemingly different sources.