All GMail Accounts At Risk - Proton

https://proton.me/blog/google-data-breach-gmail-warning

The hack exposed a systemic weakness in Google's Salesforce. It immediately captured all of the customers / client's information for every company that uses Salesforce (just about every company out there that uses e-commerce).

The hackers can generate phising emails that come from actual, validated Google accounts. Telling you that your password has been compromised and then asking you to choose a new one (twice), is as old as the hills without 2FA, but millions of people still fall for it -

One of many reasons why I don't discuss any "hobby" related items with anybody using a GMail account.

The hackers can generate phising emails that come from actual, validated Google accounts. Originally Posted by Anonymous01

No, they can't. To do that they will need password and article clearly states that those were not leaked. They still can impersonate using this data, but email would be different.

Also, it didn't capture data from every company that uses Salesforce. It captured data from Google's Salesforce database. It contained information about small and medium sized businesses that are Google customers. If that information is accurate, it is unlikely that individual gmail accounts are at any increased risk.

Tandy has the thread winning comment here ^^^
atxvitya has a close 2nd place with the impersonate sender comment, which is somewhat easy to do once you know how. aka "email spoofing".

You can learn a bit about email headers from the Googlie here

On some other email tools might be something called "View Source", likely buried under a More or Options tag somewhere.

In particular; look at the "From:" and "Reply To:" tags