Netcat 😼

Using Netcat for file transfers

• Original article

Netcat is like a swiss army knife for geeks. It can be used for just about anything involving TCP or UDP. One of its most practical uses is to transfer files. Non *nix people usually don’t have SSH setup, and it is much faster to transfer stuff with netcat then setup SSH. netcat is just a single executable, and works across all platforms (Windows,Mac OS X, Linux).

On the receiving end running,

nc -l -p 1234 > out.file

will begin listening on port 1234.

On the sending end running,

nc -w 3 10.11.74.136 777 < out.file

will connect to the receiver and begin sending file.

For faster transfers if both sender and receiver has some basic *nix tools installed, you can compress the file during sending process,

On the receiving end,

nc -l -p 1234 | uncompress -c | tar xvfp -

On the sending end,

tar cfp - /some/dir | compress -c | nc -w 3 [destination] 1234

A much cooler but less useful use of netcat is, it can transfer an image of the whole hard drive over the wire using a command called dd.

On the sender end run,

dd if=/dev/hda3 | gzip -9 | nc -l 3333

On the receiver end,

nc [destination] 3333 | pv -b > hdImage.img.gz

Be warned that file transfers using netcat are not encrypted, anyone on the network can grab what you are sending, so use this only on trusted networks.

What to do after receiving the file?

• Try to analyze it with VirusTotal