On 1 December, ZD Net reported that the FBI says that cyber-criminals are increasingly relying on email forwarding rules in order to disguise their presence inside hacked email accounts. It says the technique has been seen and abused in recent BEC (Business Email Compromise) attacks reported over the summer.
https://www.zdnet.com/article/fbi-warns-of-email-forwarding-rules-being-abused-in-recent-hacks/
I had omitted the following link (as it did not seem to generate much interest!), but it seemed time to add it again and say that, if you would like to make a (polite) gesture and help me with my removal and computer costs, I have a page at https://www.buymeacoffee.com/KoIvM842y