Config files : Improper perception of data

Shells differ greatly in the way they handle unescaped parentheses, square brackets, and arrays, which are passed as multiple arguments in eval expressions. eval command is used to execute arguments like a shell command. Arguments are joined in a string and taken as input for the shell command to execute the command. If eval passes data which is not correctly processed, the attacker will be able to find out, change or delete sensitive information from the system.