The IDF dismissed the idea that an attack of that nature would take place so they were taken by surprise. They supposedly had some intelligence warning them but didn't act on it. This article is from CNN, but I've read other articles that say the same things. It was an intelligence failure by the IDF with grave consequences.

https://www.cnn.com/2023/12/01/middleeast/israel-hamas-gaza-intelligence-intl/index.html

I don't know if Israel sacrificed the "red heifer" during passover this year. Probably not, so we still have time.