MASTER BOOT RECORD: PERSONAL COMPUTER

Introduction

The second CTF developed by MBR.

Beginning

Intruction found in their official website:

087 101 108 099 111 109 101 032 098 097 099 107 032 116 111 032 116 104 105 115
032 110 101 119 032 099 104 097 112 116 101 114 013 010 097 110 111 116 104 101
114 032 114 105 100 101 032 105 110 116 111 032 116 104 101 032 112 097 115 116
013 010 070 114 111 109 032 097 032 116 105 109 101 032 105 116 032 119 111 117
108 100 032 098 101 032 104 097 114 100 101 114 013 010 084 111 032 107 110 111
119 032 101 118 101 114 121 116 104 105 110 103 032 115 111 032 102 097 115 116
013 010 013 010 066 097 099 107 032 116 111 032 115 101 099 114 101 116 032 119
097 121 115 032 111 102 032 115 104 097 114 105 110 103 013 010 109 101 115 115
097 103 101 115 032 116 111 032 117 110 107 110 111 119 110 032 112 097 108 115
013 010 116 097 108 107 105 110 103 044 032 099 104 097 116 116 105 110 103 032
119 105 116 104 111 117 116 032 098 111 117 110 100 097 114 105 101 115 013 010
119 105 116 104 111 117 116 032 112 114 101 106 117 100 105 099 101 115 032 111
114 032 098 097 110 115 013 010 013 010 084 117 110 110 101 108 032 116 111 032
109 121 032 111 108 100 101 115 116 032 115 105 116 101 013 010 102 111 108 108
111 119 032 109 101 032 097 108 111 110 103 032 116 104 101 032 115 116 114 101
101 116 115 013 010 121 111 117 032 119 105 108 108 032 102 105 110 100 032 116
104 101 032 099 111 100 101 115 032 116 111 032 111 112 101 110 013 010 097 108
108 032 116 104 101 032 098 111 120 101 115 032 102 111 114 032 116 104 105 115
032 103 105 102 116 013 010 013 010 068 111 110 039 116 032 100 101 115 112 097
105 114 032 105 116 039 115 032 106 117 115 116 032 097 032 103 097 109 101 013
010 065 108 108 032 121 111 117 032 110 101 101 100 032 097 114 101 032 116 111
111 108 115 032 110 111 116 032 115 107 105 108 108 115 013 010 082 101 097 100
032 109 121 032 116 105 112 115 032 097 108 111 110 103 032 116 104 101 115 101
032 108 105 110 101 115 013 010 097 110 100 032 103 101 097 114 032 117 112 032
119 105 116 104 032 115 111 109 101 032 103 111 111 100 032 119 105 108 108 013
010

QuXTAUZByO4q13QU8etfs68qb7CUgKo/mzKQ3Itp+4M/WkOnAdWUmi8OylJRZrZvIC81lHGt5+xpdflh
70qRJsznz+FCZ4054NCy4gQnE9p09VR3WhQ284mdORl6XlrBCpT8Z6RXxDoI8Dq7BuA+Vl6gDg+A0c4c
1IIAlzBtzWtKvlGt0Ch2hOrcPOafPiX3rSZz81oOiznAdUWJrfTZYfVuiPU5uX9Co5S1mC5orWM3MmSq
1KizCd3nPw2o1HUlVOm2X3TTySfZWeYJO1S3reMIGjeVXY9eIbfVUn/9gZVA5hcUH4oQXj9JxCICPzB3
HWIEyHzipRkvHVbLgHrVdwuxMnIldTPzMcRAdU7qVqb6tD/KI58n4KEnHAphdJ7qdDQfn3IFSF4i1Tfd
xSmU7tAU3fn2UwSwenTVdwXyHpfksmexaBi7zoXvnVEUTb+VDgFOzO3m4JwSIn7hTdEwsnSKFmKWSzDq
n6ySLIVAwZt4DAkXn49cJ+Gmiu7ZScJyDzEaSSnzxKzeSzgtCNwvyGjGlGmxLb/T8wPMrNa5VsJ4SdYd
NgDVn+e9bV/jQ3QD+2zt2s4ighVkXjGadtdPsemYejZk4RM1HKMau+0id+f3Jbv0qkJmpY4n9jhiFjkJ
JQKOqxkbqbCKznyti+RK/Zz/Ejhz3AiwD89M4HAc1SM=

Translated (ASCII):

Welcome back to this new chapter
another ride into the past
From a time it would be harder
To know everything so fast

Back to secret ways of sharing
messages to unknown pals
talking, chatting without boundaries
without prejudices or bans

Tunnel to my oldest site
follow me along the streets
you will find the codes to open
all the boxes for this gift

Don't despair it's just a game
All you need are tools not skills
Read my tips along these lines
and gear up with some good will

Based on the introduction we can assume that:

You will have to retread some of the port numbers from the previous CTF

Important things to note (same thing as INTERNET PROTOCOL):

It's not recommended to use Telnet or PuTTY

Hidden in Plain Sight

A binary sequence is hidden in the instruction page above the ASCII string.

01110010 01100101 01101110 01100101 01110111 01100001 01101100 01101001 01110011 01101000 01100101 01110010 01100101

renewalishere

Decode the Base64 string from the instruction using the above phrase.

In the depths of rodent's lair
an enormous code to swallow
turn the words into jpegs
to reveal the way to follow

When the sky is turning black
and there's no moon there to shine
You will find a wall of words
Where the people leave their signs

There's a rider right behind me
who's the holder of the key
Look around and try to find me
In the networks open sea

Once the key is in your hands
Come back home to get your file
One in twenty one you'll find
there still waiting for your trial

Let's break this down by each stanza:

First stanza: The "rodent's lair" probably refers to Gopher and the "words into jpegs" foreshadows one of the text files that contains jpeg raw data
Second stanza: The "wall of words" where "people leave their signs" points to a graffiti wall.
Third stanza: A "rider right behind me" who's the "holder of the key" is something to keep in mind
Fourth stanza: "Come back home to get your file" and the key mentioned previously might hint to the key being a password to an unspecified file.

Rodent's Lair

Access MBR's Gopher server and download followme.txt. Convert the Base64 string into hexadecimal and paste it into an empty jpg file using a hex editor. Then you're supposed to find the location of where the picture was taken by finding the coordinates found in the metadata.

Paste the coordinates into a map and look around until you find a "rider" on the wall (Wilson).

Did you see the code?

Those who played INTERNET PROTOCOL might have noticed a locked file in the FTP directory. Putting in "Wilson" as the password unlocks PC.RAR.

file.wav when viewed as a spectrogram reveals a number sequence.

readme.txt:

Did you see the code written in the fabric of reality?

CALL MY BBS TODAY AND REDEEM YOUR PRIZE NOW!

Spread The Code

Heavy Metal is not dead.

Log in to MBR's BBS server and look through the message board until you find a message with "PERSONAL COMPUTER" as the subject:

IpIRM7T9GQwWZduOkXqLWhEqtk001Nkz/f/DDJUnssy5JozGMYZ8QdtggSyg
1+Ym8GmJTk8i+POlMEQksz4NpWgOMxXiZ/eo0MPAd8ln1Rd45M2d+9qMczYM
6ygvJw4DGDLc4qW1/rA/yUupa/eysiofnhSLvwRbpaBdsjWTf28LW6RKTjk+
ALFr6OwaxLZArsEEPlNEg/nLhFCPvkOd5DmhxzqhuQt5pJMex9lgm6wYoicz
eEIx73E0AyP05/R+w6cAuWKLu1OzFvmG2icAgPIGymafFnIQdraPdceNfOVn
ZFCp/uskRU+nc3G5U1DoGVLmp/CcFCP3HaV8NrogWA==

MASTER BOOT RECORD
Heavy Metal is not dead. It was just not evenly synthesized.

Using the number sequence in the spectrogram (71341721) as the key, decode the Base64 string using AES-256 to obtain the codeword.

End

Once you found the codeword, use that as the key to decrypt the string found in the BONUS page.

Bonus track: Advanced Micro Devices.wav