Uploaded malicious files always pose a great threat to web applications. An attacker tries to upload code to the system to be attacked; later that code is supposed to be executed. Usually, the “attack” only needs to find a way to get the code executed to own the system.
The consequences vary: it could be shell commands to be executed later; it could be just an image to declare that the web site has been hacked; or it could be more severe, including system takeover, forwarding attacks to back-end systems, and many more that also include side channel attacks. When a computer system ...
