-page-....-2f-2f....-2f-2f....-2f-2fetc-2fpasswd _best_ -

. It occurs when a web application takes user-supplied input and passes it directly to a file-handling function (like PHP's ) without proper sanitization. The Expectation : The server expects a request like ?page=contact.php and looks for it in /var/www/html/pages/ The Reality : The attacker sends ?page=../../../../etc/passwd The Result

If page=../../../etc/passwd%00 (null byte injection in older PHP), the server might read /etc/passwd . -page-....-2F-2F....-2F-2F....-2F-2Fetc-2Fpasswd

: This is a common "bypass" technique for ../ (parent directory). By using multiple dots or specific encoding, attackers try to trick security filters that only look for the standard ../ pattern. : This is a common "bypass" technique for

: Storing passwords in /etc/passwd was historically done but considered insecure. Modern systems use shadow passwords stored in /etc/shadow , which is only readable by root, enhancing security. Modern systems use shadow passwords stored in /etc/shadow