CVE-2016-10996 in optinmonster Plugin
Summary
by MITRE
The optinmonster plugin before 1.1.4.6 for WordPress has incorrect access control for shortcodes because of a nonce leak.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/26/2023
The vulnerability identified as CVE-2016-10996 affects the optinmonster plugin for WordPress versions prior to 1.1.4.6, representing a critical access control flaw that undermines the security posture of affected websites. This issue stems from a nonce leak within the plugin's shortcode implementation, creating a pathway for unauthorized users to execute privileged actions without proper authentication. The vulnerability specifically impacts the plugin's ability to verify user permissions when processing shortcode requests, allowing attackers to bypass intended access restrictions and potentially perform administrative functions.
The technical flaw manifests through the improper handling of cryptographic nonces within the plugin's shortcode processing mechanism. Nonces serve as time-limited tokens designed to prevent unauthorized execution of actions by ensuring that requests originate from legitimate sources with proper authorization. In this case, the nonce values are being exposed or improperly validated, creating a scenario where attackers can predict or reuse nonce values to gain elevated privileges. This vulnerability directly relates to CWE-352, which encompasses Cross-Site Request Forgery (CSRF) weaknesses, and more specifically aligns with CWE-284, which addresses improper access control mechanisms. The leak allows attackers to exploit the plugin's functionality through maliciously crafted shortcode requests that appear to originate from authenticated users.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to manipulate various aspects of the WordPress site through the optinmonster plugin. An attacker could potentially modify plugin settings, create or delete opt-ins, manipulate campaign data, or even gain full administrative control of the affected WordPress installation. The vulnerability affects not only the immediate plugin functionality but also compromises the broader security model of the WordPress platform, particularly when multiple plugins are installed and may share similar access control patterns. This issue demonstrates how seemingly isolated plugin vulnerabilities can create cascading security risks within complex web applications.
Mitigation strategies for CVE-2016-10996 require immediate action to upgrade the optinmonster plugin to version 1.1.4.6 or later, which contains the necessary fixes for the nonce handling mechanism. System administrators should also implement additional security measures including regular plugin audits, monitoring for unauthorized changes to plugin files, and ensuring that all WordPress components remain updated. The vulnerability highlights the importance of proper nonce generation and validation practices as outlined in the OWASP Top Ten and MITRE ATT&CK framework's privilege escalation techniques. Organizations should conduct comprehensive security assessments of their WordPress installations, focusing on plugin access control mechanisms and implementing automated monitoring to detect potential exploitation attempts. Additionally, implementing web application firewalls and restricting access to administrative interfaces can provide additional layers of defense against such vulnerabilities.