Once a variable is tainted, Perl will allow you to use it in a system() , exec() , piped open, eval() , backtick , or unlink command.

Question

Quizplus · Accepted Answer

Perl does not allow the use of tainted variables in sensitive operations like system(), exec(), piped open, eval(), backticks, or unlink command to prevent security vulnerabilities such as code injection attacks. Taint mode is specifically designed to track untrusted user input and prevent it from being used in a potentially dangerous manner.

Once a Variable Is Tainted, Perl Will Allow You to Use