• You can sign up to this mailing list set up by HOPO to receive information about available theses and projects advertised by professors
• You can also check projects published on SiROP
• IBM research often publishes Master thesis proposals on their website
• You can always approach the professor / PhD student from a group of interest

You might want to have a look at the following course before starting your thesis to get comfortable using the shell: The Missing Semester of Your CS Education