A critical security vulnerability, identified as CVE-2022-4253, has been discovered in the SourceCodester Canteen Management System, which is widely used to oversee and manage daily canteen operations. The vulnerability specifically impacts the 'builtin_echo' function of the 'customer.php' file, resulting in a cross-site scripting (XSS) attack vector. As this problem has been publicly disclosed, anyone with malicious intent can potentially exploit the issue to cause damage. The vulnerability has been assigned the identifier VDB-214630.

Original References

CVE: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-4253
VDB: https://vulners.com/oval/VDB-214630

Exploitation Details

The core issue lies in the 'builtin_echo' function of the 'customer.php' file, wherein improper sanitization of user input allows attackers to inject malicious scripts into the web application. With a successful attack, the malicious script executes in the context of the user's browser session, potentially leading to unauthorized access, information leakage, or even complete control over the user's session.

The vulnerable section of code in the 'customer.php' file is as follows

<?php
  function builtin_echo($input) {
    echo $input;
  }

  $user_data = $_GET['user_data'];
  builtin_echo($user_data);
?>

The code above demonstrates that the 'builtin_echo' function directly outputs the value returned by the '$_GET['user_data']' variable without properly sanitizing it, hence rendering the application susceptible to XSS attacks.

Attack Scenario

An attacker can exploit this vulnerability by crafting a URL that includes malicious JavaScript code. When the targeted user clicks on the URL or visits the link, the attacker's script will execute in the user's browser.

Example of a crafted URL

http://vulnerable_canteen_management_system/customer.php?user_data=<script>alert('XSS')</script>;

Upon visiting the page with the above URL, the user will see an alert box with the message "XSS" displayed, proving that the Javascript code was executed.

Mitigation and Recommendations

To prevent the exploitation of this vulnerability, developers must ensure proper user input validation and sanitization. One recommended approach is to utilize PHP output encoding functions, such as 'htmlspecialchars', to neutralize potentially malicious input:

<?php
  function builtin_echo($input) {
    echo htmlspecialchars($input, ENT_QUOTES, 'UTF-8');
  }

  $user_data = $_GET['user_data'];
  builtin_echo($user_data);
?>

Additionally, it is crucial to keep the SourceCodester Canteen Management System updated to the latest version, as future releases may include patches for this vulnerability.

Conclusion

The CVE-2022-4253 vulnerability in the SourceCodester Canteen Management System's 'customer.php' file can lead to severe repercussions, such as unauthorized access to sensitive data or hijacking of user sessions. It is essential to address this XSS vulnerability by implementing proper user input validation and sanitization mechanisms and staying updated with the software's newest releases to protect the application and its users from potential attacks.

Timeline

Published on: 12/01/2022 08:15:00 UTC
Last modified on: 12/02/2022 18:43:00 UTC