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Vulnerability DatabaseCVE-2021-28931

CVE-2021-28931: 
PHP vulnerability analysis and mitigation

Overview

Fork CMS version 5.9.2 contains an arbitrary file upload vulnerability (CVE-2021-28931) that was disclosed on July 7, 2021. The vulnerability allows attackers to create or replace arbitrary files in the /themes directory of the content management system (NVD).

Technical details

The vulnerability exists in the Themes panel of the settings tab, where authenticated users can upload new themes. An attacker can craft a custom zip file containing malicious code and a .htaccess file to create arbitrary files in the Themes folder. The .htaccess file can be configured to instruct the web server to execute new file types under the web application context (GitHub POC).

Impact

A successful exploitation of this vulnerability can result in complete web server compromise, particularly in shared hosting environments. Additionally, attackers can gain access to the database since they can read/access configuration files (GitHub POC).

Mitigation and workarounds

To mitigate this vulnerability, developers should implement proper file sanitization during theme uploads, specifically to disallow .htaccess files. Users should upgrade to a version newer than 5.9.2 (GitHub POC).

Additional resources

Source: This report was generated using AI

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