Writing and defending a MSc thesis is an important part of the Cyber Security curriculum, as it shows that you can go deep into a specific cyber security research area. This page gives a rough overview over the process, but details should be discussed with your supervisor. This overview part is given according to the assumption that you are following 4 semester study plan and aim to defend in June period. If you want to defend in January, then you can adjust the planning phases accordingly.
Generally the process should start during the first year, by finding a topic-area of interest and by identifying a suitable supervisor. At the end of the second semester, you should have an idea about your topic and you should have discussed this with your supervisor.
It is recommended that you take the literature review seminar in the 3rd semester. The purpose of this seminar is two-fold: (a) you need to do a literature review for your thesis anyway (e.g., see here), and (b) learning from others about research-papers they have read for their thesis broadens your overall horizon and should help you in discussing challenges you are facing in your own literature review.
The purpose of the literature review is that you obtain a good understanding of the state-of-the-art research in your selected area of research. Typically during this reading phase, the problem statement (the question you aim to address/solve in your thesis) will be refined/changed. You should aim to have a solid problem statement fixed and agreed with your supervisor during the 3rd semester, ideally well before December.
In early December, you should submit a problem statement and research design document. Sending this document is considered as registration to the defence that will take place in next term.
The next step in the process would be conducting the research. Please reserve sufficient time for this, as this is going to be the main contribution of your thesis. Plan to finish this work early April, so that your supervisor can review your thesis, give you feedback and you have time to address the feedback before your thesis is being sent to the reviewer/opponent. Jointly with your supervisor you should then make a decision if your work is ready to be submitted for June defence (or if you need more time and prefer to submit for a January defence). For students planning to defend in June, expected deadline to submit your thesis for review, to be around late April. For students aiming to defend in January, expect early December. The opponent will review your thesis and give you feedback. Clearly, you will be allowed to continue working on your thesis, but keep in mind any results or insights that you produce during that time won't be visible to your opponent. You can and should, however, include them in the final copy of your thesis and defence presentation. Expect that you should receive the review from your opponent about a week or two before the final deadline. This will allow you to make minor modifications, e.g., fix some typos or clarify some sections, which the reviewer pointed out.
At the final submission deadline, you will have to submit your thesis. On the day of defence, you are expected to give a 15 minute presentation of your work, followed by Q&A from the opponent, committee, supervisor and audience. Make sure you prepare your 15 min presentation well, this should not be left for the evening before the defence.