Java Snippet #03
This challenge covers the review of a snippet of code written in Java
The Code Review Snippet challenges are designed to test your ability to identify vulnerabilities in small code snippets. Initially, you should attempt to find any issues on your own. If you need assistance or want to confirm your findings, you can watch the accompanying video. In this challenge, the focus is on a Java class named MyParser that processes XML input. The method parseData takes a user-supplied string, converts it into a byte array, and parses it as an XML document.
The key issue in this code is that it uses DocumentBuilderFactory to parse XML without disabling support for XML entities. This can be exploited to load local or external files, potentially leading to Server-Side Request Forgery (SSRF) or local file read vulnerabilities. It’s crucial for developers to disable XML entity support when dealing with untrusted XML input to prevent such attacks. This challenge highlights the importance of properly configuring XML parsers to avoid severe security flaws.