CVE-2021-36874 in uListing Plugin
Summary
by MITRE • 09/28/2021
Authenticated Insecure Direct Object References (IDOR) vulnerability in WordPress uListing plugin (versions
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Analysis
by VulDB Data Team • 10/02/2021
The authenticated insecure direct object reference vulnerability in the WordPress uListing plugin represents a critical authorization flaw that allows authenticated users to access restricted resources they should not be able to reach. This vulnerability falls under the CWE-639 category of Authorization Flaws, specifically targeting the improper enforcement of access controls within web applications. The issue stems from the plugin's failure to properly validate user permissions when processing requests for listings, user data, or other sensitive resources. Attackers with valid user accounts can manipulate object references such as listing IDs, user IDs, or other resource identifiers to gain unauthorized access to data belonging to other users or system resources. The vulnerability exists due to insufficient input validation and inadequate access control checks within the plugin's core functionality.
The technical implementation of this vulnerability occurs when the uListing plugin processes user requests without properly verifying whether the authenticated user has legitimate authorization to access the requested resource. This typically manifests when the application accepts direct object references from user input without implementing proper authorization checks. The flaw allows attackers to construct malicious requests by modifying parameters such as listing IDs, user IDs, or other object identifiers that are used to directly reference database records or system resources. The vulnerability is particularly dangerous because it operates within the authenticated context, meaning that an attacker needs only a valid user account to exploit the flaw, making it more accessible than many other authorization bypass vulnerabilities. The plugin's API endpoints and administrative functions are particularly susceptible to this type of attack, where the lack of proper access control validation enables unauthorized data access and potential information disclosure.
The operational impact of this vulnerability extends beyond simple data exposure, potentially enabling more severe consequences including user data manipulation, privacy violations, and unauthorized administrative actions. An attacker could leverage this vulnerability to view private listings, access confidential user information, or even modify listings belonging to other users. The implications are particularly concerning in real estate or directory listing platforms where sensitive personal information, contact details, and business data are commonly stored. This vulnerability can result in significant privacy breaches and regulatory compliance violations under data protection frameworks such as gdpr and ccpa. The attack surface is further expanded when considering that the vulnerability affects multiple versions of the plugin, meaning a large number of WordPress installations could be at risk. Organizations using the uListing plugin may face reputational damage, legal consequences, and financial losses resulting from unauthorized data access and potential data breaches.
Mitigation strategies for this vulnerability should focus on implementing proper access control validation and input sanitization measures throughout the plugin's codebase. The recommended approach involves adding comprehensive authorization checks before processing any user requests that involve object references, ensuring that each request is validated against the authenticated user's permissions. This includes implementing proper parameter validation, using secure coding practices such as prepared statements and input sanitization, and enforcing role-based access controls where appropriate. Organizations should immediately update to patched versions of the uListing plugin when available, as vendors typically release security updates to address such authorization flaws. Additionally, implementing network-level monitoring and logging of API requests can help detect and respond to exploitation attempts. The vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation, as the attack leverages legitimate user credentials to access unauthorized resources. Security teams should also consider implementing web application firewalls and access control policies to prevent unauthorized access patterns and monitor for suspicious parameter manipulation attempts.