Here is the video demonstration of how one can snoop on each command entered by a user, essentially a keylogger. This can be done by creating a malicious bash binary and replacing with original bash binary on the system with it.
The first task is to grab the raw source code of bash and than analyze about placing our malicious code.
Once this is done, we inject malicious code to send off every command to a UDP server, which we can implement using python.
NOTE : Only for PROOF OF CONCEPT PURPOSES. Do not use this methodology for malicious purposes.