Q10. On average, how long does it take to discover a breach in a network?

On average, how long does it take to discover a breach in a network? (Q10 from #GCAchat 21 May 2020)

(@basquecscentre) Response: The most optimistic estimates show that it takes at least 49 days to discover that someone has accessed your network without authorization. It is essential to keep our devices up-to-date.