Course

In this exercise, we explore a vulnerability that arises when applications handle zip files or other archives. Specifically, the issue occurs when an archive contains a symbolic link—a special file that points to another file. By uploading a zip file with a symbolic link and extracting it, an attacker can access files outside the web root, such as `/etc/passwd`, which they should not normally be able to access. This vulnerability can be exploited to read arbitrary files from the server, posing a significant security risk.

The video guides you through creating a zip file, adding a symbolic link, and uploading it to the vulnerable application. It shows the steps to verify the contents of the zip file and demonstrates how the symbolic link can be used to gain unauthorized access. This exercise not only focuses on zip files but also highlights how this pattern can be extended to other formats and situations. Understanding and mitigating this vulnerability is crucial for developers to ensure the security of their applications.