CVE-2013-0731 in Wp-mailup
Summary
by MITRE
ajax.functions.php in the MailUp plugin before 1.3.3 for WordPress does not properly restrict access to unspecified Ajax functions, which allows remote attackers to modify plugin settings and conduct cross-site scripting (XSS) attacks by setting the wordpress_logged_in cookie. NOTE: this is due to an incomplete fix for a similar issue that was fixed in 1.3.2.
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Analysis
by VulDB Data Team • 02/25/2019
The vulnerability described in CVE-2013-0731 affects the MailUp plugin for WordPress, specifically targeting the ajax.functions.php file in versions prior to 1.3.3. This issue represents a critical access control flaw that undermines the security posture of WordPress installations using this plugin. The vulnerability stems from insufficient validation of user permissions within the plugin's Ajax handling mechanism, creating a pathway for unauthorized modifications to plugin configurations and potential execution of malicious scripts.
The technical flaw manifests in the improper restriction of access to unspecified Ajax functions within the MailUp plugin. When attackers manipulate the wordpress_logged_in cookie, they can bypass authentication checks that should normally prevent unauthorized access to administrative functions. This weakness allows malicious actors to escalate privileges and gain access to plugin settings that should only be available to authenticated administrators. The vulnerability is particularly concerning because it leverages existing authentication mechanisms rather than requiring additional credentials, making it more difficult to detect and prevent.
The operational impact of this vulnerability extends beyond simple privilege escalation to include potential cross-site scripting attacks that can compromise user sessions and data integrity. Attackers exploiting this vulnerability can modify plugin configurations, potentially disabling security features or redirecting user traffic to malicious destinations. The XSS component of this vulnerability means that compromised users may be subjected to further attacks including credential theft, session hijacking, or redirection to phishing sites. The incomplete fix referenced in the CVE description indicates that the developers addressed a similar issue in version 1.3.2 but failed to fully resolve the underlying access control mechanisms, leaving the system vulnerable to the same class of attacks.
This vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and demonstrates how incomplete security fixes can leave systems exposed to continued exploitation. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and credential access methods, as attackers can leverage existing authentication cookies to gain elevated privileges. The attack vector involves manipulating session cookies to impersonate legitimate users, which represents a common technique in modern web application exploitation. Organizations using the MailUp plugin should immediately upgrade to version 1.3.3 or later to remediate this vulnerability and prevent potential compromise of their WordPress installations. The issue highlights the importance of comprehensive security testing and the dangers of partial fixes that address symptoms rather than root causes of security flaws.
The remediation strategy for this vulnerability requires immediate patching of the MailUp plugin to version 1.3.3 or higher, which contains the complete fix for the access control issues. System administrators should also implement additional monitoring for suspicious cookie manipulation attempts and review plugin access logs to detect potential exploitation attempts. Network security controls including web application firewalls should be configured to detect and block unusual Ajax request patterns that may indicate exploitation attempts. Regular security audits of WordPress plugins and themes should be conducted to identify similar access control vulnerabilities that could provide attackers with unauthorized access to administrative functions.