Telling your contacts not to use Google nor Meta/Facebook. If everyone you email use gmail, then Google has all your emails.

Knowledge of the account is an obvious caveat. Yubikey-based MFA is an added layer of protection for accounts, so any kind of attack against MFA assumes the attacker already knows which account to target.

It’s like saying “our door lock is flawed, but the attacker would need to have knowledge of the door”.

The cost and complexity is what’s noteworthy and is more relevant. Although attack cost and complexity usuallu goes down with advances in tooling and research. So it may be a good idea to plan a progressive retirement of affected keys.

While that’s true, but there’s no indication of Microsoft brute forcing with million of combinations.

The article you link says Microsoft is only trying a few obvious passwords: the filename, and words found in the plaintext message.

Proper encryption isn’t just about using a strong algorithm. It’s also about proper key management, ie not sending the password in the clear via the same channel as the encrypted files.

ZIP isn’t a good way to encrypt, but what Microsoft is doing is simply reading the email, and decrypting zips with the password found in the email body.

All encryptions schemes can be trivially broken if you have the key. It’s not even breaking, it’s just normal decryption.

Quite the contrary.

Password hashing is standard nowadays.

When a database is compromised, brute forcing hashes is necessary to recover passwords, and the short ones are the first ones to be recovered.