The Cyber Grabs CTF Walkthrough
I am going to explain Crypto Challenge in this walkthrough, so going ahead.
First I want to thank to my partner @mohit. We were part of this CTF (team:BYT3_3XPL0!T) ) and we secured 29th position. We both were happy since it was unexpected :P .
Now lets start
1. Training
In this challenge the string was given which was in hexadecimal form , so we used online tool to convert this Hex into ASCII and found our flag.
2. binary_binary
This challenge was about “how strong is your binary skills”. In this challenge long Binary(1 and 0) string was given. So we have to convert it into ASCII. After converting it, we found this string “IF YOU WANT TO GET FLAG DECODE THIS 666c61677b434f4e47524154537d”. Since it was in hex, we decoded it and found our flag.
3. mr_robot
The above binary value was given, so we used CyberChef (Best online tool for Crypto challenges) to decode it, after decoding we found base32 value(there was “==” in the last). So after decoding it again we received our flag :)
4.Based
In this challenge we have to download this txt file. after downloading we received below long string “UEsDBAoACQAAAEG8BlHgDIXfNgAAACoAAAAJABwAZmxhZzEudHh0VVQJAAMSRixfEkYsX3V4CwABBOgDAAAE6AMAAFsOM9iwtX7srByZEWmCvS8sJehZbFTufs9nMmT9yafuoqmg2o5G/ze0gqIkJh6FIKOobZdx5FBLBwjgDIXfNgAAACoAAABQSwECHgMKAAkAAABBvAZR4AyF3zYAAAAqAAAACQAYAAAAAAABAAAAtIEAAAAAZmxhZzEudHh0VVQFAAMSRixfdXgLAAEE6AMAAAToAwAAUEsFBgAAAAABAAEATwAAAIkAAAAAAA==”
Then we decoded this string by our cyberchef and we got this
We identified there was a flag1.txt file in the output. Now our challenge was to find this flag1.txt file.
There are lot of online tools which converts base64 into file. So we used https://base64.guru/converter/decode/file and got our file named “application.zip”. During the extract this zip file, we required password. Here we used our favourite tool fcrackzip and rockyou password list for bruteforce to get our password
Now we got our password “hacker”. So extracted the zip file and got our flag.
Amazing !!
5. Ancient one
Those who play CTF regularly, can easily recognise this cipher is Morse.
So we used https://www.boxentriq.com/code-breaking/morse-code to decode and then we got “DECRYPTTHEFOLLOWING 66 6C 61 67 7B 4D 30 72 73 33 5F 43 30 64 33 7D”. After decoding this hex string and received our flag.
6. not_for_you
This challenge is solved by my team mate. In this challenge they gave us hint as some language , so we used google translator
So we found this text is in Filipino language and in next block we found a string and cipher “bazeries”. So we decoded it “tvmdukvfhdcho” by bazeries cipher and got our flag.
