MAPNA CTF

MAPNA CTF WriteUP

Hello comrades, I’m glad you came here to read my article about MAPNA CTF

Let’s start now

PLC I

I opened plc.pcap and read it once, what caught my eye was the form flag lol 1: MAPNA{y

Ok then I understand, just search and arrange in order :_)

MAPNA{y0u_sHOuLd_4lW4yS__CaR3__PaADd1n9!!}

What next?

from Crypto.Util.number import long_to_bytes

def decrypt(enc, KEY):
    m = enc ^ KEY
    return long_to_bytes(m).decode('utf-8')

# Given values
KEY = 23226475334448992634882677537728533150528705952262010830460862502359965393545
enc = 2290064970177041546889165766737348623235283630135906565145883208626788551598431732

# Decrypt the flag
flag = decrypt(enc, KEY)

print("Decrypted flag:", flag)

MAPNA{R_U_MT19937_PRNG_Predictor?}

Flag Holding

Now let’s use Burp Suite to intercept the request from the web, then throw it through the Repeater

And here, the topic says you are not from this address http://flagland.internal/

Then we will add the header Referer:http://flagland.internal/

And it says Unspecified "secret"

So we just need to add param “secret” to the request and because this is a GET request, the url will be inserted

We have received the next hint secret is the protocol that both the server and browser use to communicate, so we add http

Noo !!!

The problem says there is no accept GET but FLAG, so let’s change GET to FLAG @~@

MAPNA{533m5-l1k3-y0u-kn0w-h77p-1836a2f}

goodbye, thank you for reading until now //~//