OverTheWire: Bandit 11-15
Welcome to another post on our series of OverTheWire Bandit! This post covers my walkthrough of levels 11-15. If you would like to jump to specific level then each level with be accompanied with the username and password. I will be appending consecutive levels as I have to time to post. Enjoy!
Bandit 11
http://overthewire.org/wargames/bandit/bandit11.html
The password for the next level is stored in the file data-orginal.txt, which contains base64 encoded data
Lucky for us there is a utility called base64. Let see what the built-in help tells us.
bandit10@bandit:~$ base64 --help
Usage: base64 [OPTION]... [FILE]
Base64 encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --decode decode data
-i, --ignore-garbage when decoding, ignore non-alphabet characters
-w, --wrap=COLS wrap encoded lines after COLS character (default 76).
Use 0 to disable line wrapping
--help display this help and exit
--version output version information and exit
The data are encoded as described for the base64 alphabet in RFC 4648.
When decoding, the input may contain newlines in addition to the bytes of
the formal base64 alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Full documentation at: <http://www.gnu.org/software/coreutils/base64>
or available locally via: info '(coreutils) base64 invocation'
Seeing as the data-orginal.txt file is encoded the -d or --decode parameter looks like what we need.
bandit10@bandit:~$ base64 --decode data-orginal.txt
The password is IFukwKGsFW8MOq3IRFqrxE1hxTNEbUPR
Username: bandit11 Password: IFukwKGsFW8MOq3IRFqrxE1hxTNEbUPR
Bandit 12
http://overthewire.org/wargames/bandit/bandit12.html
The password for the next level is stored in the file data-orginal.txt, where all lowercase (a-z) and uppercase (A-Z) letters have been rotated by 13 positions
This means that it was encrypted with the ROT13 algorithm. In order to decrypt it, we have to replace every letter by the letter 13 positions ahead thus abc..xyz becomes:
Input ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz Output NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm
A useful tool to use would be tr. This tool can translate, squeeze, and/or delete characters from standard input.
bandit11@bandit:~$ cat data-orginal.txt | tr A-Za-z N-ZA-Mn-za-m
The password is 5Te8Y4drgCRfCx8ugdwuEX8KFC6k2EUu
Helpful Reading Material
Username: bandit12 Password: 5Te8Y4drgCRfCx8ugdwuEX8KFC6k2EUu
Bandit 13
http://overthewire.org/wargames/bandit/bandit13.html
First we need to make a temporary directory as suggested to unzip the files. Then copy data-orginal.txt and convert the ASCII text to binary (basically hexdump the content), for that we’ll be using xxd.
bandit12@bandit:~$ mkdir /tmp/me0w
bandit12@bandit:~$ cp data.txt /tmp/me0w/data-orginal.txt
bandit12@bandit:~$ cd /tmp/me0w
bandit12@bandit:/tmp/[me0w$ ls
data-orginal.txt
bandit12@bandit:/tmp/me0w$ xxd -r data-orginal.txt > data.bin
Next we want to figure out what the properties of the file are, for that we’ll use file.
bandit12@bandit:/tmp/me0w$ file data.bin
data.bin: gzip compressed data, was "data2.bin", from Unix, last modified: Fri Nov 14 10:32:20 2014, max compression
Awesome! Let’s decompress it.
bandit12@bandit:/tmp/me0w$ gzip -d data.bin
gzip: data.bin: unknown suffix -- ignored
Uh oh! gzip expects a proper extension, let’s rename it.
bandit12@bandit:/tmp/me0w$ mv data.bin data.gz
bandit12@bandit:/tmp/me0w$ gzip -d data.gz
bandit12@bandit:/tmp/me0w$ ls
data data-orginal.txt
Let’s inspect it again with file like we did before.
bandit12@bandit:/tmp/me0w$ file data
data: bzip2 compressed data, block size = 900k
Looks like this one is compressed via bzip. No worries we’ll just do the same as before except we need to rename the file extension to .bz2.
bandit12@bandit:/tmp/me0w$ mv data data.bz2
bandit12@bandit:/tmp/me0w$ bzip2 -d data.bz2
bandit12@bandit:/tmp/me0w$ ls
data data-orginal.txt
bandit12@bandit:/tmp/me0w$ file data
data: gzip compressed data, was "data4.bin", from Unix, last modified: Fri Nov 14 10:32:20 2014, max compression
Only a few more times…
bandit12@bandit:/tmp/me0w$ mv data data.gz
bandit12@bandit:/tmp/me0w$ gzip -d data.gz
bandit12@bandit:/tmp/me0w$ ls
data data-orginal.txt
bandit12@bandit:/tmp/me0w$ file data
data: POSIX tar archive (GNU)
Meanwhile… 
Did you watch it until the end? Okay sorry let’s get back to it…
bandit12@bandit:/tmp/me0w$ mv data data.gz
bandit12@bandit:/tmp/me0w$ gzip -d data.gz
bandit12@bandit:/tmp/me0w$ ls
data data-orginal.txt
bandit12@bandit:/tmp/me0w$ file data
data: POSIX tar archive (GNU)
bandit12@bandit:/tmp/me0w$ mv data data.tar
bandit12@bandit:/tmp/me0w$ tar -xvf data.tar
data5.bin
bandit12@bandit:/tmp/me0w$ file data5.bin
data5.bin: POSIX tar archive (GNU)
bandit12@bandit:/tmp/me0w$ mv data5.bin data5.tar
bandit12@bandit:/tmp/me0w$ tar -xf data5.tar
bandit12@bandit:/tmp/me0w$ tar -xf data5.tar
bandit12@bandit:/tmp/me0w$ mv data5.bin data5.tarl^C
bandit12@bandit:/tmp/me0w$ ls
data-orginal.txt data5.tar data6.bin
bandit12@bandit:/tmp/me0w$ rm data5.tar
bandit12@bandit:/tmp/me0w$ file data6.bin
data6.bin: bzip2 compressed data, block size = 900k
bandit12@bandit:/tmp/me0w$ mv data6.bin data6.bz2
bandit12@bandit:/tmp/me0w$ bzip2 -d data6.bz2
bandit12@bandit:/tmp/me0w$ ls
data-orginal.txt data6
bandit12@bandit:/tmp/me0w$ file data6
data6: POSIX tar archive (GNU)
bandit12@bandit:/tmp/me0w$ mv data6 data6.tar
bandit12@bandit:/tmp/me0w$ tar -xf data6.tar
bandit12@bandit:/tmp/me0w$ ls
data-orginal.txt data6.tar data8.bin
bandit12@bandit:/tmp/me0w$ rm data6.tar
Is this ever going to end?! 
bandit12@bandit:/tmp/me0w$ file data8.bin
data8.bin: gzip compressed data, was "data9.bin", from Unix, last modified: Fri Nov 14 10:32:20 2014, max compression
bandit12@bandit:/tmp/me0w$ mv data8.bin data8.gz
bandit12@bandit:/tmp/me0w$ gzip -d data8.gz
bandit12@bandit:/tmp/me0w$ ls
data-orginal.txt data8
bandit12@bandit:/tmp/me0w$ file data8
data8: ASCII text
bandit12@bandit:/tmp/me0w$ cat data8
The password is 8ZjyCRiBWFYkneahHwxCv3wb2a1ORpYL
Got it!
Username: bandit13 Password: 8ZjyCRiBWFYkneahHwxCv3wb2a1ORpYL
Bandit 14
http://overthewire.org/wargames/bandit/bandit14.html
The password for the next level is stored in /etc/bandit_pass/bandit14 and can only be read by user bandit14. For this level, you don’t get the next password, but you get a private SSH key that can be used to log into the next level. Note: localhost is a hostname that refers to the machine you are working on
This one is fairly simple. Just ssh into the next host using the private key provided.
bandit13@bandit:~$ ls
sshkey.private
bandit13@bandit:~$ ssh bandit14@localhost -i sshkey.private
Could not create directory '/home/bandit13/.ssh'.
The authenticity of host 'localhost (127.0.0.1)' can't be established.
ECDSA key fingerprint is SHA256:98UL0ZWr85496EtCRkKlo20X3OPnyPSB5tB5RPbhczc.
Are you sure you want to continue connecting (yes/no)?
...
bandit14@bandit:~$
Here’s a brief diagram explaining how SSH Private/Public keys work: 
Now we just have to cat the password file for the current level like so.
bandit14@bandit:~$ cat /etc/bandit_pass/bandit14
4wcYUJFw0k0XLShlDzztnTBHiqxU3b3e
Username: bandit14 Password: 4wcYUJFw0k0XLShlDzztnTBHiqxU3b3e (Also uses sshkey.private file)
Bandit 15
http://overthewire.org/wargames/bandit/bandit15.html
The password for the next level can be retrieved by submitting the password of the current level to port 30000 on localhost.
For the sake of being brief within this post I would suggest learning about a tool called netcat aka ncat - The Network Swiss Army Knife. Essentially netcat is a utility capable of establishing a TCP or UDP connection between two computers, meaning it can write and read through an open port.
bandit14@bandit:~$ cat /etc/bandit_pass/bandit14
4wcYUJFw0k0XLShlDzztnTBHiqxU3b3e
bandit14@bandit:~$ cat /etc/bandit_pass/bandit14 | ncat localhost 30000
Correct!
BfMYroe26WYalil77FoDi9qh59eK5xNr
For all you Network+ guys think client-server model. The beauty of ncat is that it is capable being both the client and the server aka listener and sender. This is a great tool for sysadmins, network engineers, and hackers.
nc <options> <host> <port>
Username: bandit15 Password: BfMYroe26WYalil77FoDi9qh59eK5xNr