CVE-2021-24818 in WP Limits Plugin
Summary
by MITRE • 12/13/2021
The WP Limits WordPress plugin through 1.0 does not have CSRF check when saving its settings, allowing attacker to make a logged in admin change them, which could make the blog unstable by setting low values
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/15/2021
The vulnerability identified as CVE-2021-24818 affects the WP Limits WordPress plugin version 1.0 and earlier, representing a critical security flaw that undermines the integrity of WordPress administrative functions. This issue stems from the absence of Cross-Site Request Forgery (CSRF) protection mechanisms within the plugin's settings management interface, creating a significant attack vector for malicious actors who can manipulate administrative configurations without proper authorization. The vulnerability specifically impacts the plugin's ability to validate legitimate administrative requests, leaving the WordPress installation exposed to unauthorized modifications that could severely compromise system stability and functionality.
The technical flaw manifests in the plugin's failure to implement proper CSRF token validation when processing administrative settings updates. This absence of validation allows attackers to craft malicious requests that appear to originate from legitimate administrative sessions, exploiting the trust relationship between the WordPress admin interface and the plugin's configuration endpoints. The vulnerability operates at the application layer and directly violates established security principles for protecting administrative functions, as outlined in CWE-352 which categorizes CSRF as a fundamental web application security weakness. Attackers can leverage this flaw by tricking logged-in administrators into visiting malicious websites or by directly submitting crafted requests that modify plugin settings, potentially setting dangerous configuration parameters that disrupt normal blog operations.
The operational impact of this vulnerability extends beyond simple configuration changes, as the malicious modification of plugin settings can lead to system instability and potential service disruption. When attackers manipulate the WP Limits plugin settings to establish low values, they can create conditions that cause the blog to become unresponsive or functionally impaired, as the plugin may enforce restrictions that are too severe for normal operational requirements. This type of attack represents a sophisticated approach to compromising WordPress systems, as it targets the administrative configuration layer rather than directly exploiting core WordPress vulnerabilities, making detection more challenging and potentially allowing attackers to maintain persistence within the system. The vulnerability aligns with ATT&CK technique T1059.001 which covers command and script injection, as attackers can effectively use the compromised administrative interface to inject malicious configurations that alter system behavior.
Organizations affected by this vulnerability should immediately implement multiple layers of mitigation strategies to protect their WordPress installations. The most immediate and effective solution involves updating to the latest version of the WP Limits plugin where CSRF protection has been implemented and validated. Administrators should also review their current plugin configurations and monitor for unauthorized changes to administrative settings, implementing additional security controls such as two-factor authentication and restricted administrative access. Network-level protections including web application firewalls and monitoring for suspicious administrative requests can help detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and CSRF protection in web applications, as highlighted in the OWASP Top Ten 2017 category A03: Injection, which emphasizes the need for comprehensive protection of administrative interfaces against unauthorized modifications that can compromise system integrity and availability.