The Covert Channel Educational Analysis Protocol (CCEAP) is a simple network protocol designed for teaching covert channels (network steganography) to professionals and students. It is also an easy-to-use covert channel traffic generator.
The protocol is explicitly vulnerable against several hiding patterns, i.e. patterns that represent hiding methods (steganographic methods that create covert channels, see here for my GitHub online class on network steganography/covert channels). The protocol's structure is simple and self-explanatory and its implementation is kept at a minimum level of code lines to make it especially accessible to students. There is also a documentation and an academic publication (published under the umbrella of ACM CCS 2016, download link is also in the documentation) available.
Please send requests and feedback to the author: Steffen Wendzel, www.wendzel.de (steffen (at) wendzel (dot) de).
Steffen Wendzel, Wojciech Mazurczyk: Poster: An Educational Network Protocol for Covert Channel Analysis Using Patterns, in Proc. 2016 ACM SIGSAC Conference on Computer and Communications Security (CCS 2016). ACM, New York, NY, USA, pp. 1739–1741, DOI: 10.1145/2976749.2989037.
First, start the server, e.g. on your local host: ./server -P 9999. This lets the server run on IP 127.0.0.1, port 9999.
Then, connect with the client: ./client -D 127.0.0.1 -P 9999. This will make the client send ten simple standard messages to your server. The server should display the received packets' meta-data.
Now, let us create a simple covert timing channel that we use to transfer the file /etc/hosts. And we want to encode 1 and 0 bits with 500ms and 1000ms. Therefore, we start the server again, and then run the client as follows using CCEAP's iat_encode tool which encodes files into inter-arrival times (this would represent the Inter-arrival Time pattern):
./client -D 127.0.0.1 -P 9999 -t ´./iat_encode /etc/hosts 500 1000´
Of course, one could also use dd together with /dev/random as a source of randomness to create a file with random bits and use this file instead of /etc/hosts.
Similarly, the Manipulated Message Ordering pattern can be represented using ./seq_encode /etc/hosts 256 2 instead of ./iat_encode /etc/hosts 500 1000. Check the documentation for details.
More parameters of client can be obtained by running ./client -h.
Additional examples can be found in the sample_exercises directory and in the documentation.