elFinder Local File Inclusion Scanner

elFinder is a web-based file manager that is commonly used in content management systems, personal websites, and other types of web applications to provide users with a graphical interface for managing files on a server. Developed by the vendor std42, elFinder enables users to upload, delete, copy, and search files conveniently from a web browser, acting as a bridge between users and server-side file systems. It is highly versatile and finds application among web developers and system administrators who require flexible file management tools. The software is integrated into various platforms owing to its open-source nature, offering customization capabilities to fit specific user needs. Its dynamic and user-friendly design contributes to enhancing the overall user experience in web environments. As an asset widely used in managing web content, it has been adopted across numerous platforms globally.

The Local File Inclusion (LFI) vulnerability in elFinder allows attackers to include files that exist on the server, which are supposed to be outside the web folder or not accessible. This vulnerability leverages a flaw in file path processing, enabling attackers to navigate through directories and access potentially sensitive files. The exploitation of LFI can be done remotely without authentication, making it particularly dangerous. It can facilitate unauthorized file reading, thus exposing sensitive application and system files to unauthorized entities. The impact includes the unauthorized viewing of the content of files, which might include configuration files or files containing sensitive data. In some scenarios, it could also be used to further escalate attacks if the compromised file has code that could be executed.

The technical specifics of this LFI vulnerability allow attackers to exploit an endpoint named 'Connector.minimal.php'. The file parameter accepts file paths which are improperly sanitized, allowing traversal to directories outside the application's root directory. Attackers can make HTTP GET requests that manipulate the file path parameter with traversal sequences such as '../../../', eventually leading to sensitive files like '/etc/passwd'. The use of such endpoints in elFinder widens attack vectors significantly, as unauthenticated attackers gain unintended access. Despite existing mitigations, improper path validation in the elFinder framework continues to pose challenges. As such, security teams must identify and rectify these types of weaknesses promptly to prevent exploit facilitation.

When leveraged by attackers, this type of file inclusion vulnerability may result in severe data breaches and unauthorized data access. It can expose sensitive server information and facilitate subsequent attacks, such as gaining server control or extracting sensitive data. The risk extends to a potential full server compromise, particularly when configuration files are accessed or manipulated. Other possible risks include the introduction of malicious scripts or payloads if combined with a code execution vulnerability. The overall threat landscape could see the server used as a relay for attacks or for storing malicious content, compromising server integrity and security measures.

REFERENCES

• https://www.synacktiv.com/publications/elfinder-the-story-of-a-repwning.html