SquirrelMail Local File Inclusion Scanner

SquirrelMail is a widely used open-source webmail package, primarily used by businesses and educational institutions to enable email access through web browsers. Its easy integration with existing mail servers makes it beneficial for system administrators looking for a simple email client. The software's customizable nature allows developers to create plugins, catering to the unique needs of organizations. SquirrelMail supports multiple languages, enhancing its global adoption. Administrators use it to provide web-based email solutions without the need for additional client software installation. Being a part of numerous server setups, its security is of utmost importance to maintain data privacy.

The Local File Inclusion (LFI) vulnerability involves an attacker tricking the server into executing or exposing files on the web server. In SquirrelMail, improper input validation in certain scripts can lead to this vulnerability. This flaw can be exploited by malicious users to execute arbitrary code in the context of the application. LFI occurs when a web application uses user input to access files and does not properly sanitize the input, allowing for directory traversal sequences. If exploited, attackers can gain unauthorized access to sensitive files. LFI can lead to serious impacts like data leaks and potentially further system compromise.

The technical aspect of the Local File Inclusion vulnerability in SquirrelMail lies in the ability to manipulate script parameters such as `mailbox` to access unintended files. The endpoint, specifically `read_body.php`, is susceptible to this exploitation. Attackers may access system files like `/etc/passwd`, which should be inaccessible. The GET parameter `mailbox` does not undergo sufficient sanitization, permitting directory traversal. This can be confirmed by inspecting the server's response to crafted requests that embed malicious paths. Ensuring the parameter check adheres strictly to predefined acceptable patterns can mitigate this risk.

Exploiting the LFI vulnerability in SquirrelMail can grant unauthorized users access to sensitive system files. It can potentially expose application configuration files containing database credentials. In extreme cases, if combined with other vulnerabilities, it could be used to execute remote code on the server, leading to a complete system breach. This could allow attackers to modify or delete stored emails or use the server to perform phishing attacks. The breach of personal data could lead to reputational damage and loss of customer trust for organizations using SquirrelMail.

REFERENCES

• https://www.exploit-db.com/exploits/22793