CVE-2011-0759 in WP-reCAPTCHA
Summary
by MITRE
Multiple cross-site request forgery (CSRF) vulnerabilities in the configuration page in the Recaptcha (aka WP-reCAPTCHA) plugin 2.9.8.2 for WordPress allow remote attackers to hijack the authentication of administrators for requests that disable the CAPTCHA requirement or insert cross-site scripting (XSS) sequences via the (1) recaptcha_opt_pubkey, (2) recaptcha_opt_privkey, (3) re_tabindex, (4) error_blank, (5) error_incorrect, (6) mailhide_pub, (7) mailhide_priv, (8) mh_replace_link, or (9) mh_replace_title parameter.
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Analysis
by VulDB Data Team • 10/21/2021
The CVE-2011-0759 vulnerability represents a critical cross-site request forgery flaw in the WP-reCAPTCHA WordPress plugin version 2.9.8.2, specifically targeting the plugin's configuration interface. This vulnerability operates under the weakness category identified by CWE-352, which classifies cross-site request forgery as a fundamental web application security flaw. The vulnerability exists within the administrative configuration page of the plugin, making it particularly dangerous as it allows unauthenticated remote attackers to manipulate the plugin's settings through crafted requests. The attack vector leverages the fact that the plugin fails to implement proper CSRF protection mechanisms, specifically lacking anti-CSRF tokens or similar validation measures that would normally prevent unauthorized modifications to administrative settings.
The technical implementation of this vulnerability affects multiple parameters within the plugin's configuration system, including recaptcha_opt_pubkey, recaptcha_opt_privkey, re_tabindex, error_blank, error_incorrect, mailhide_pub, mailhide_priv, mh_replace_link, and mh_replace_title. These parameters control various aspects of the CAPTCHA functionality and mailhide features, allowing attackers to modify critical configuration values that could disable CAPTCHA protection entirely or inject malicious XSS payloads. The vulnerability specifically targets the plugin's administrative interface, meaning that successful exploitation would grant attackers the ability to modify the plugin's behavior and potentially compromise the entire WordPress installation. Attackers could disable CAPTCHA requirements, making the site more vulnerable to automated spam and bot attacks, or inject malicious JavaScript code that would execute in the context of administrator sessions.
The operational impact of this vulnerability extends beyond simple configuration manipulation, as it creates a pathway for more sophisticated attacks within the WordPress environment. When administrators access the compromised plugin configuration page, they unknowingly execute malicious requests that modify critical security settings. This vulnerability directly violates the principle of least privilege and authentication integrity, as it allows remote attackers to perform administrative actions without proper authentication. The attack can be executed through social engineering techniques where administrators are tricked into visiting malicious websites or clicking on compromised links that automatically submit CSRF requests to the vulnerable WordPress installation. The vulnerability also contributes to a broader attack chain that could lead to complete system compromise, as disabling CAPTCHA protection makes the site more susceptible to brute force attacks and automated exploitation attempts.
Mitigation strategies for CVE-2011-0759 should prioritize immediate plugin updates to versions that address the CSRF vulnerability, as the original affected version 2.9.8.2 contains no built-in protections against this class of attack. Security administrators should implement additional protective measures including the enforcement of CSRF tokens in all administrative interfaces, regular monitoring of plugin configuration changes, and the implementation of web application firewalls that can detect and block suspicious parameter modifications. The vulnerability's classification under CWE-352 indicates that it represents a fundamental architectural flaw that requires systematic remediation rather than simple patching. Organizations should also consider implementing role-based access controls and regular security audits of WordPress plugins to identify similar vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and persistence through configuration modification, making it a critical target for defensive security operations that focus on protecting administrative interfaces and maintaining the integrity of web application settings.