Rating:
# Catch This Flag!
- Category: PPC
- Rating: medium
This was a really fun challenge involving a healthy amount of cats.
We are given a ip to connect to along with 10 ports, `46470-46479`, connecting to any of them usually gets us this response
```bash
Sorry, No cats here... # As I remember it
```
but every once in a while you get this
```bash
_._ _,-'""`-._
(,-.`._,'( |\`-/|
`-.-' \ )-`( , o o) # Closest approximation I could find to ascii nyan cat
`- \`_`"'-
Your part of the flag is:63
Next port: 46473
```
But when we go there we just get this again
```bash
Sorry, No cats here...
```
No dice. We need to automate this.
# Solution
Summoning pwntools and re makes the code a breeze. We just hammer the ports till we get a response, then we parse the next port and hammer that one until we get its part of the flag and so on...
```python
#!/usr/bin/env python
import re
from pwn import *
context.log_level = 'critical'
port = 46470
flag = ''
started = 0
prev = ''
while True:
con = remote('188.130.155.66', port)
text = con.recv()
# print text
if "cats" in text: # No cats here...
if started == 0:
port += 1
con.close()
continue
elif "flag" in text: # Your part of the flag is:43
started = 1 # Next port:46473
port = int(re.findall('4647.',text)[0])
prev = re.findall('Your part of the flag is:..', text)[0][-2:]
if prev == flag[-2:] and flag != '':
continue
flag += prev
print flag
con.close()
```
This is how running it looked like during the CTF
# Flag
`InnoCTF{49fe100103cbc466c7ba22c373636a56d}`
