A study of APT campaigns from 2008 to 2020 found that APTs rarely rely on zero-days during campaigns User tweedge, in the cybersecurity subreddit, 20 May 2022
[2205.07759] Software Updates Strategies: a Quantitative Evaluation against Advanced Persistent Threats User digicat, in the For [Blue|Purple] Teams in Cyber Defence subreddit, 19 May 2022