You want how many citations for ransomware, malware, side channel attacks, impersonated apps, cyber attacks?
I can provide 100,000.
But if you haven’t noticed 100,000 items in the news in recent times then there is something deeply wrong with you.
And Tim Cook certainly has noticed these 100,000 items in the news.
Steve Jobs himself said in 2008 that unscrupulous developers were trying to hide malicious activity inside their binaries.
If you don’t know that, you need to sit back, observe, learn and be a good student of life.