HakTip 88 – Cryptcat: Netcat Using Two-Fish Encryption

This week on HakTip Shannon is trying out Cryptcat, Netcat with Encryption!

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Cryptcat is another command line tool that is built on top of Netcat and works almost exactly the same. We’ve discussed the fact that Netcat usage is transmitted in plain text, meaning there is no encryption and anyone can see what you are doing across computers. Cryptcat gives you a version of Netcat using two-fish encryption. I was able to download it on my Linux Mint machine by simply typing into the terminal: sudo apt-get install cryptcat.

Now type Cryptcat -h. You’ll notice that a lot of the options for Cryptcat are the same as Netcat. It also uses the same commands.

Here’s an example for you:

On my computer – I type “cryptcat -k mypassword 1337”. Cryptcat opens cryptcat. -k does enables the password or the symmetric key (which means both of us need to know that key). The next word if my password, then the ip address of the other computer. The last bit is my port.

On Darren’s computer, he will type “cryptcat -k mypassword -l -p 1337”. Cryptcat again, opens cryptcat. -k does enabled the password. Again, Darren puts in our shared password, then -l listens. -p 1337 means listen on port 1337.

Now on to the fun part. Cryptcat says it’s encrypted. I’m going to open wireshark with “gksudo wireshark &” to make sure. I’ll choose eth0 for my LAN, and type “tcp.port == 1337” into the filter box at the top. Now lets try chatting again.

You’ll notice a bunch of packets get transmitted between us, but all of them are encrypted.

Now, if we chat via Netcat. I’ll be the listener this time. Open with “nc -l -p 1337” and Darren uses “nc 1337”.

Now, lets go back to Wireshark and watch the packets roll in as we chat. You’ll notice that these chats ARE NOT encrypted.

Do you use Cryptcat? Send me a comment below or email us at [email protected]

And be sure to check out our sister show, Hak5 for more great stuff just like this. I’ll be there, reminding you to trust your technolust.


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