Description
This guy named Simon gave me a bunch of tasks to complete and not a lot of time. He wants to run a unique zoo but needs the names for his animals. Can you help me?
nc challs.actf.co 31402
Approach
when we connect to the server using nc we receive a prompt: Combine the first 3 letters of {animal name} with the last 3 letters of {animal name}
However, we are need to provide the correct answer within 5 seconds and repeat this more than 10 times. Manually doing this task is not feasible, but this can be easily automated with a python script
#!/usr/bin/env python3
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('challs.actf.co', 31402))
while True:
response = s.recv(1024).decode().strip()
if response.startswith("actf{"):
print(f"Received flag: {response}")
break
words = response.split()
if len(words) < 7:
print(f"Invalid response: {response}")
break
answer = f"{words[6][:3]}{words[-1][-3:]}"
print(f"Request: {response}")
print(f"Response: {answer}")
print("\n")
s.sendall(answer.encode() + b"\n")
s.close()
I attempted to run the script on my local machine, but didn’t recieved any flag. However, when I used Google Shell, it worked without any issues. I think this could be latency issue.
Flag: actf{simon_says_you_win}