Why’s that even relevant if the recipient is the wrong address? Email isn’t particularly secure anywhere, and gmail has forwarding and IMAP and aliases and other services that send emails outside of gmail. But sending sensitive documents to the wrong recipient, which was the topic that started this sub-thread, is a case where it does not matter how secure your servers are.

> [...] and gmail has forwarding and IMAP and aliases and other services that send emails outside of gmail.

No matter what format you hand a recipient a document in, they can always make a photocopy and pass it on.

Sure. How’s that relevant?

That someone might use IMAP is no worse than someone using a photocopier.

Sure it is, and your own comment above about gmail to gmail being fairly secure demonstrated that. Using a photocopier is intentional, and everyone knows what a photocopier is. Most people don’t know what IMAP is, and an email sender does not know if the recipient uses IMAP.

And this is still irrelevant to sending email to the wrong recipient, so I don’t know why you’re stuck on infra security.

Gmail can be fetched via IMAP and leave Gmail's infra entirely. And I don't think Google guarantees that their implementation stays fully on their own owned infra. It's a reasonable assumption but I'd never trust that for a security guarantee.

Email is not an end-to-end secure data protocol without the use of client side encryption/decryption like PGP/GPG, but even then, sender/receiver and time are all in the envelop metadata.

Yeah, that exactly my point - no idea why I’m being downvoted on this

Probably because Law Firms arent necessarily computer security firms. Lots of people have terrible op sec. Additionally if you the recipient are on gmail it stops mattering, now Google knows your legal woes.

Exactly, I’d never use Gmail for anything sensitive. Even for just personal emails I use my own mailserver. (And again, for truly sensitive stuff I don’t use email at all)

If the sender is using GMail, then using your own mail server is less secure than using GMail as the receiver.

Sure even though, as most others, my server supports TLS, having your email not leave gmail at all may be slightly more secure. Part of the point however was that when either server or receiver is using Gmail, your possibly confidential email content is still in Google’s hands. Using a personal server reduces that part of the attack surface. Still this does not mean I vacate my overall point that email in general is suboptimal from a secop standpoint.

Even if the law firm uses a Gmail account - which most of course don’t - Google still has access to your sensitive legal email content. (And that’s apart from the meta data leaking)

if you attach documents by linking to a Google Drive document, sure.

if you attach documents 'inside' the mail (i.e. MIME encoded multipart) that is most definitely not secure.

1) you do not know how that mail gets delivered, not necessarily via servers that support encryption 2) you do not know how that mail, or the attachment, gets stored on the local machine 3) you do now know if the mail, or attachment, is sent to someone else 4) you cannot revoke the access to the document once the Need To Known stops

In our ISMS, sending Highly Sensitive data (ex: customer data) by attaching directly to a mail, is strictly not allowed by the IT charter. We explain it during an on-boarding meeting to all new staff members. And it's a fireable offense.