Java Snippet #09
This challenge covers the review of a snippet of code written in Java
In this Code Review Snippet challenge, we examine the Java class Fetcher.java. The code attempts to fetch data from a given URL using HTTPS. However, it overrides the default hostname verification by always returning true, which poses a significant security risk. This allows any hostname in the certificate to be accepted, regardless of the URL being connected to, making it susceptible to Man-in-the-Middle (MitM) attacks.
The code starts by importing necessary libraries and creating a class called Fetcher with a method named fetch that takes a string URL. Inside this method, the code sets a default HostnameVerifier that always returns true, effectively bypassing any hostname verification. This means an attacker with a valid TLS certificate can intercept the TLS connection because the hostname in the certificate is not verified against the URL. The code then opens an HTTPS connection, reads the data, and prints it. Finally, it handles exceptions by printing the stack trace for debugging purposes.