CVE-2018-20979 in contact-form-7 Plugin
Summary
by MITRE
The contact-form-7 plugin before 5.0.4 for WordPress has privilege escalation because of capability_type mishandling in register_post_type.
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Analysis
by VulDB Data Team • 12/01/2023
The vulnerability identified as CVE-2018-20979 affects the contact-form-7 plugin for WordPress versions prior to 5.0.4, representing a critical privilege escalation issue stemming from improper capability_type handling within the register_post_type function. This flaw allows attackers to escalate their privileges within the WordPress environment, potentially gaining unauthorized access to administrative functions and sensitive data. The vulnerability specifically targets the plugin's implementation of WordPress's custom post type registration system, where the capability_type parameter fails to properly restrict access to certain administrative operations.
The technical root cause lies in how the contact-form-7 plugin registers its custom post types without adequately validating or restricting the capabilities required to perform administrative actions. When WordPress processes the register_post_type function, it uses the capability_type parameter to determine which user roles can perform specific operations such as creating, editing, or deleting posts. In this case, the plugin's implementation fails to properly enforce capability checks, allowing users with insufficient privileges to perform actions that should require higher-level permissions. This misconfiguration creates a pathway for attackers to bypass standard WordPress access controls and escalate their privileges within the system.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to manipulate the contact-form-7 plugin's functionality in ways that compromise the entire WordPress installation. An attacker could potentially modify or delete contact forms, access sensitive form data, or even use the privilege escalation to gain full administrative control over the WordPress site. This vulnerability aligns with CWE-269: Improper Privilege Management, which addresses issues where software fails to properly enforce access controls and privilege boundaries. The flaw demonstrates how improper handling of capability types in custom post type registration can create security holes that undermine the fundamental access control mechanisms of the WordPress platform.
Security professionals should consider this vulnerability in relation to the ATT&CK framework's privilege escalation techniques, particularly those involving the abuse of application vulnerabilities to gain elevated permissions. The impact on WordPress security is significant because contact-form-7 is one of the most widely used contact form plugins, making this vulnerability attractive to attackers seeking to compromise WordPress installations at scale. Organizations running affected versions of the plugin should prioritize immediate remediation through the official 5.0.4 update, which addresses the capability_type mishandling by implementing proper access control checks. Additionally, administrators should conduct thorough security audits of their WordPress installations to identify other potential privilege escalation vectors and ensure that all plugins maintain proper capability enforcement mechanisms. The vulnerability underscores the importance of proper security testing for custom post type implementations and highlights how seemingly minor configuration errors in WordPress plugin development can have severe consequences for overall system security.