6.5. The Dangers of read and eval

We’ve used both the eval and the read commands in creating a custom Lisp REPL. These commands are very powerful, but also very dangerous. Using them without taking the proper precautions might allow a hacker to attack your software by running malicious commands.

For example, suppose our program needed a function called format-harddrive. This is not a function we would want just any person to have access to, and it could be very dangerous if a hacker somehow tricked our game REPL into calling it.