"Application of Neural Networks in Cybersecurity," There are publications of various applications, which allows you to choose the one that is most related to your interests.
Kind regards
Professor Legon.
Hint: A quick Google scholar search will give you many examples
As you are most interested in conducting research on the implementation of machine learning in cyber security, so I propose the following research topic for your thesis: Analysis of the technological and economic determinants of the feasibility and validity of implementing machine learning technologies to improve cyber security systems and instruments. Within the framework of this topic, you can consider the possibilities of combining machine learning technology with other Industry 4.0 technologies to increase the possibility of improving cyber security systems and instruments. This topic may refer to improved cyber-security systems and instruments in public institutions, commercially operating non-financial business entities, or in banks and other financial institutions offering their services and financial products via the Internet, i.e., through online and mobile banking. An important element of the aforementioned issue of improving cyber-security systems and instruments through the use of machine learning and possibly other Industry 4.0 technologies is improving the performance of spam filters, whose task is to catch fake e-mails falling into e-mail inboxes containing hidden malware, ransomware viruses, viral Trojan horses, etc.