CVE-2022-4534 in Limit Login Attempts Plugin
Summary
by MITRE • 10/08/2024
The Limit Login Attempts (Spam Protection) plugin for WordPress is vulnerable to IP Address Spoofing in versions up to, and including, 5.3. This is due to insufficient restrictions on where the IP Address information is being retrieved for request logging and login restrictions. Attackers can supply the X-Forwarded-For header with with a different IP Address that will be logged and can be used to bypass settings that may have blocked out an IP address or country from logging in.
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Analysis
by VulDB Data Team • 10/11/2024
The Limit Login Attempts plugin for WordPress presents a critical security vulnerability through its improper handling of IP address information in versions up to and including 5.3. This flaw stems from the plugin's reliance on HTTP headers such as X-Forwarded-For for determining client IP addresses without adequate validation or sanitization mechanisms. The vulnerability creates a pathway for attackers to manipulate the plugin's security controls by injecting false IP addresses through these headers, effectively circumventing the very protections the plugin was designed to provide.
The technical implementation of this vulnerability occurs at the network layer where the plugin accepts IP address data from HTTP headers without proper verification of their authenticity. The X-Forwarded-For header is commonly used by web proxies and load balancers to identify the original IP address of a client connecting to a web server through an HTTP proxy or load balancer. However, when the plugin blindly trusts this header without additional validation, it allows malicious actors to submit arbitrary IP addresses that will be logged and treated as legitimate client addresses. This behavior directly violates security principle of least privilege and input validation, creating a condition where attackers can spoof their location to bypass IP-based restrictions.
The operational impact of this vulnerability extends beyond simple bypass of login restrictions. An attacker who successfully spoofs an IP address can circumvent country-based blocking mechanisms, evade IP blacklists, and potentially overwhelm login attempt counters to cause legitimate users to be locked out of their accounts. The vulnerability affects the core security functionality of the plugin, which is designed to protect WordPress installations from brute force attacks and automated login attempts. When an attacker can bypass these protections, they gain increased opportunities to perform unauthorized access attempts without detection or restriction, potentially leading to full system compromise.
This vulnerability aligns with CWE-284 Access Control Issues and specifically demonstrates improper input validation in network security contexts. The flaw represents a classic case of trust but verify, where the plugin assumes that HTTP headers contain valid information without implementing proper verification mechanisms. From an attack perspective, this vulnerability maps to multiple ATT&CK techniques including T1110 Targeted Social Engineering and T1078 Valid Accounts, as it enables attackers to bypass access controls and potentially gain unauthorized access to WordPress administrative interfaces. The attack surface is particularly concerning in environments where the plugin is used alongside other security measures, as it creates a potential backdoor that undermines the effectiveness of the entire security stack.
The recommended mitigation strategies include immediate patching to versions that address the IP address spoofing vulnerability, implementing additional validation of HTTP headers, and configuring web servers to properly sanitize or remove potentially malicious headers before they reach the WordPress application. Organizations should also consider implementing multi-factor authentication and additional monitoring of login attempts to detect anomalous behavior that might indicate header manipulation attempts. Network-level controls such as web application firewalls can provide additional protection by filtering out suspicious header values, though the most effective solution remains the patching of the vulnerable plugin to properly validate IP address information sources.