If you are using the Appointment Hour Booking WordPress plugin for scheduling appointments on your website, it's important to note that the plugin has been found to be vulnerable to iFrame injection attacks. Versions up to and including 1.3.72 are affected due to insufficient input sanitization and output escaping. iFrame injection can be a severe security risk as it can lead to unauthenticated attackers being able to execute malicious scripts on your website. In this long read, we will discuss the details of this vulnerability (CVE-2022-4035), how it can be exploited, and the necessary steps to be taken to resolve the issue.

Exploit Details

The vulnerability exists in the 'email' and general field parameters of the Appointment Hour Booking plugin. Due to the lack of proper input sanitization, it is possible for an attacker to inject iFrame tags when submitting a booking. These iFrames can execute malicious code whenever a user accesses the injected booking details page, causing potential harm to the site and its users. Unauthenticated attackers can exploit this vulnerability to carry out a range of malicious activities, such as phishing attacks or distributing malware.

An attacker sends a booking request using the Appointment Hour Booking form

<form action="https://vulnerable-wordpress-site.com/booking-handler/"; method="POST">
  <input type="text" name="email" value="<iframe src='https://malicious-site.com/'></iframe>"; />
  <input type="text" name="name" value="John Doe" />
  ...
  <input type="submit" value="Book Appointment" />
</form>

2. The malicious iFrame tag is injected into the website's database due to insufficient input sanitization:

<iframe src='https://malicious-site.com/'></iframe>

3. When a user or website administrator views the booking details page, the injected iFrame code is executed, potentially compromising the security of the site and its users.

References

1. Original Vulnerability Advisory: CVE-2022-4035
2. Appointment Hour Booking WordPress Plugin: Plugin Page

Solution

The first step in resolving this issue is to verify if you are running a vulnerable version of the Appointment Hour Booking plugin. If you are using version 1.3.72 or lower, it is advised to update the plugin as soon as possible to avoid the security risk.

Next, it is recommended to implement proper input sanitization and output escaping. Input sanitization should be used to validate and clean user input before processing it, while output escaping should be used to filter all data that is output to the browser. These steps can help prevent iFrame injection vulnerabilities in your applications.

htmlspecialchars($string, ENT_QUOTES, 'UTF-8') for output escaping

It is also critical to monitor your website for any signs of attacks or unauthorized access. Implementing security plugins, routine security audits, and keeping your software up-to-date can help you protect your site and its users from potential threats.

Conclusion

CVE-2022-4035 highlights the importance of proper input sanitization and output escaping in web applications, especially for those that handle sensitive data. By addressing this vulnerability, you can greatly improve the security of your website and mitigate the risk of iFrame injection attacks. Taking the necessary precautions and staying informed about new vulnerabilities can help you maintain a more secure online presence.

Timeline

Published on: 11/29/2022 21:15:00 UTC
Last modified on: 12/01/2022 22:08:00 UTC