CVE-2021-36877 in uListing Plugin
Summary
by MITRE • 09/28/2021
Cross-Site Request Forgery (CSRF) vulnerability in WordPress uListing plugin (versions
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Analysis
by VulDB Data Team • 10/03/2021
The CVE-2021-36877 vulnerability represents a critical cross-site request forgery flaw discovered in the WordPress uListing plugin, affecting versions up to and including 3.3.1. This vulnerability resides within the plugin's handling of user authentication and request validation mechanisms, creating a significant security risk for WordPress installations that utilize this listing management solution. The issue stems from the plugin's failure to properly implement anti-CSRF tokens in its administrative functions, allowing malicious actors to execute unauthorized actions on behalf of authenticated users. The vulnerability specifically impacts the plugin's ability to verify the authenticity of requests originating from legitimate administrative interfaces, making it susceptible to exploitation through carefully crafted malicious requests.
The technical implementation of this CSRF vulnerability occurs at the application layer where the uListing plugin processes administrative operations without sufficient validation of request origins or authenticity. Attackers can leverage this flaw by crafting malicious web pages or emails that, when visited by an authenticated administrator, automatically submit requests to the vulnerable plugin's endpoints. The vulnerability manifests when the plugin fails to validate the presence of anti-CSRF tokens or referer headers that would normally prevent unauthorized requests from being processed. This weakness directly maps to CWE-352, which categorizes cross-site request forgery vulnerabilities as a critical class of web application security flaws. The flaw operates by bypassing the standard WordPress authentication mechanisms, allowing attackers to perform administrative actions such as modifying listings, deleting content, or potentially escalating privileges within the affected WordPress installation.
The operational impact of this vulnerability extends beyond simple data manipulation, as it can enable attackers to compromise entire WordPress installations through the uListing plugin. When an administrator visits a malicious page containing embedded CSRF payloads, the vulnerability allows unauthorized modifications to listing data, potentially leading to defacement, data loss, or even complete compromise of the affected website. The attack vector typically involves social engineering techniques where administrators are tricked into visiting malicious websites or opening compromised email attachments. This vulnerability particularly affects websites that rely heavily on user-generated content management through the uListing plugin, as it can result in unauthorized modifications to listings, user accounts, or administrative settings. The risk is amplified when administrators have elevated privileges, as the CSRF attack can potentially be used to gain deeper access to the WordPress system or exploit other interconnected vulnerabilities.
Mitigation strategies for CVE-2021-36877 should prioritize immediate patching of the uListing plugin to version 3.3.2 or later, which contains the necessary security fixes. Organizations should also implement additional defensive measures including monitoring for unauthorized administrative actions, implementing proper input validation, and ensuring that all WordPress plugins are regularly updated to their latest secure versions. Network-level protections such as web application firewalls can help detect and block malicious CSRF requests, while security awareness training for administrators can reduce the risk of social engineering attacks. The vulnerability's classification under ATT&CK technique T1548.002 highlights the importance of privilege escalation prevention and the need for robust session management controls. Regular security audits of WordPress installations should include verification of plugin integrity and proper implementation of CSRF protection mechanisms, with particular attention to the authentication and authorization flows within third-party plugins. Organizations should also consider implementing additional security controls such as two-factor authentication for administrative accounts and regular security scanning to identify similar vulnerabilities across their web applications.