Port Knocking

Challenge

During target enumeration, you find information that suggests if you port knock the sequence TCP/1000, TCP/2000, TCP/3000, this will open some firewalled ports on the box

Solution

hping3

# -n : numeric output
# -c 1 : 1 packet
# -i 1 : wait 1 second between packets
# -S : set the TCP SYN flag on the packet
for port in {1000,2000,3000}; do sudo hping3 10.9.9.14 -n -c 1 -i 1 -S -p "$port"; done