UEditor Arbitrary File Upload Scanner

UEditor is a popular web-based editor developed and maintained by Baidu, widely used for content creation in web applications. It allows seamless integration into websites and provides a rich set of tools to assist users in editing text and multimedia content. The editor is suitable for web developers and content managers looking to enhance the user interface of their websites. Although particularly known for its use in blogging and content management systems, it can also be deployed in any web platform needing enhanced text editing functionalities. UEditor supports multiple languages, making it a versatile solution for international projects. The software is open-source and customizable, allowing developers to adapt it according to specific requirements.

The Arbitrary File Upload vulnerability in UEditor occurs when an attacker exploits the file upload functionality to upload malicious files, such as PHP scripts, into the server. This flaw often arises from improper validation and filtering of the file types during the upload process. As an attacker uploads a PHP file, it leads to a potential remote code execution if executed on the server. This vulnerability is mainly due to inadequate security checks allowing any file type to be uploaded without restrictions. Consequently, remote attackers can gain unauthorized access or control over the server by uploading undesirable executable files. Such vulnerabilities highlight the critical need for ensuring secure file upload mechanisms in web applications.

The vulnerability specifically affects the PHP version of UEditor, where the file upload logic is not appropriately secured. The vulnerable endpoint is the action_upload.php file, which processes file upload requests. Attackers can manipulate the CONFIG parameters in the URL query to accept PHP files and bypass size restrictions. By crafting a multipart/form-data POST request that includes a PHP payload, the uploaded file is stored on the server and can be subsequently executed via a GET request. The exploit relies heavily on the lack of proper validation mechanisms allowing unrestricted access to dangerous file operations. A successful attack renders the server susceptible to further exploits, potentially compromising the entire system.

The exploitation of the Arbitrary File Upload vulnerability in UEditor can have serious consequences. Successful attacks could lead to remote code execution, enabling attackers to run unauthorized commands on the server. This breach can result in unauthorized data access, modification, or complete system takeover. There might also be the installation of backdoors for persistent access, further increasing the risk and damage to the server. The integrity of the affected system can be compromised, leading to data breaches and potential loss of sensitive information. Additionally, it poses significant security risks to the users of applications employing this vulnerable version of UEditor.

REFERENCES

• https://www.rescuetime.com/focus/url/https%3A%2F%2Fwww.cnblogs.com%2Fzhibing%2Fp%2F16893839.html%23_4