CVE-2018-8893 in Z-BlogPHP
Summary
by MITRE
Z-BlogPHP 1.5.1 Zero has CSRF in plugin_edit.php, resulting in the ability to execute arbitrary PHP code.
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Analysis
by VulDB Data Team • 01/20/2020
The vulnerability identified as CVE-2018-8893 affects Z-BlogPHP version 1.5.1 Zero and represents a critical cross-site request forgery flaw located within the plugin_edit.php component. This vulnerability stems from the absence of proper anti-CSRF token validation mechanisms in the administrative plugin editing interface, creating a pathway for malicious actors to manipulate the application's functionality through crafted requests. The flaw allows attackers to execute arbitrary PHP code on the target server, potentially leading to complete system compromise.
The technical implementation of this vulnerability resides in the plugin_edit.php file where user input is processed without adequate verification of the request source or authenticity. The system fails to validate the presence and validity of anti-CSRF tokens that should be required for any administrative actions involving plugin modifications. This absence of token validation creates a condition where authenticated users can be tricked into executing unintended administrative operations through maliciously crafted web requests. The vulnerability specifically targets the administrative interface of Z-BlogPHP, making it particularly dangerous as it could allow attackers to modify or replace plugins with malicious code, potentially establishing persistent backdoors or gaining unauthorized access to the entire blogging platform.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it enables attackers to manipulate the core functionality of the web application. Once exploited, the attacker can modify existing plugins, upload malicious plugins, or even replace core application files, leading to complete system compromise. This vulnerability directly violates the principle of least privilege and authentication controls, as it allows unauthorized code execution without proper authorization. The attack vector typically involves social engineering techniques where users are tricked into visiting malicious websites or clicking on compromised links that automatically submit requests to the vulnerable plugin editing interface. This type of vulnerability is classified under CWE-352, which specifically addresses Cross-Site Request Forgery issues, and aligns with ATT&CK technique T1059.007 for execution through PHP scripts.
Mitigation strategies for CVE-2018-8893 require immediate implementation of anti-CSRF token validation throughout the administrative interfaces of Z-BlogPHP installations. Organizations should ensure that all administrative actions, particularly those involving plugin modifications, require valid anti-CSRF tokens that are generated per session and validated server-side. The recommended approach includes implementing proper token management mechanisms, including token regeneration after successful authentication, and ensuring that all requests to plugin_edit.php and similar administrative endpoints contain and validate appropriate security tokens. Additionally, administrators should implement network-level protections such as web application firewalls that can detect and block suspicious requests targeting known vulnerable endpoints, while also ensuring that the application is running the latest patched versions of Z-BlogPHP to eliminate this vulnerability entirely.