In the face of the global epidemic, digital transformation of enterprises is imperative. New business models bring new opportunities, but they also extend more risks. In Q4 2020 alone, over 10 listed companies in Taiwan suffered extortion by professional hacker groups. Tens of millions of dollars of Ransoms caused heavy operating losses. Against long-term latent APT attacks, traditional passive external defenses, such as anti-virus software and firewalls, are no longer sufficient. How can MIS and IT personnel, who stands on the front line of information security, build a comprehensive defense strategy? In this forum, the senior technical manager of UPAS will share the practical experience of UPAS engaged in intranet security management for nearly 20 years: from APT kill chain analysis, ransomware attack types, to each corresponding defense link, introducing a joint defense mechanism, in order to help companies resist targeted ransomware attacks in the post-epidemic era.