[http://ctf.infosecinstitute.com/] Level2 writeup
Link: http://ctf.infosecinstitute.com/ctf2/exercises/ex2.php Very simple challenge. About php eval function: http://php.net/manual/en/function.eval.php PHP code injection: https://www.owasp.org/index.php/Direct_Dynamic_Code_Evaluation_('Eval_Injection') eval funtion takes our input and excutes it as php code. Two operands must be number so we will inject our code in to into operator. Thinking for a while I come up with this.