4 ms·

Interesting, including the comments on HN. But personally I wonder more when we can disable old TLS versions for MTAs

jeroenhd 8y ago
A lot of MTAs are improperly configured. There's still a lot of plain text email sent across the Internet. The secure mail servers often have trouble connecting to anything with a TLS version higher than 1.0 (if even that). Many mail servers also don't have a valid server certificate (self-signed, expired or even from the wrong domain). In my opinion, the email ecosystem is hopeless with regards to TLS security. Gmail started showing red padlocks for plaintext or insecurely sent emails a while back and I still see the red pad lock to this day. Bexause of this, disabling old TLS versions could make your server unreachable for large parts of the Internet or have servers fall back to plain text if they're improperly configured. Nobody wants to be that one company that can't receive your grandma's emails so everybody just keeps accepting improper configuration. Another problem is that a lot of MDA servers share their TLS config with the MTA side. I know from experience (worked at a small company that upgraded their email servers to TLS 1.2, at least on the MDA side) that old Microsoft mail clients (Office 2007 and lower, Windows Live Mail 2012) have trouble with TLS 1.2, especially on older Windows versions. Although these clients have all been deprecated for a long time, a lot of users with few tech skills still use them because that's what their PC was set up with years ago when they bought it, or because they don't want to waste their time learning how to deal with a new UI (you can see this with a lot of elderly people). For programs that use the Windows 7 TLS libraries TLS 1.2 is even disabled by default in Windows 7 because at the time Windows 7 launched, other implementations had major bugs. It can be enabled using a registry key though. This includes Office 2010, which still gets security fixes from Microsoft. So, if a large company would disable TLS 1.0/1.1 on their MTAs it might get a large amount of customer support calls from their least technical customer base. You can tell your customers that their program is out of date and that their program is the reason they're getting errors, but in the end the customer will still blame you for "breaking their mail program". Aside from a massive blow to a company's reputation, this would also overload the customer support desk and cost a lot of man hours. <edit> Actually, I've seen the built in mail app for Samsung smart phones fail on TLS 1.2 for Android versions up to Android 8. Other Android vendors generally have trouble up to Android 5/6. With the lack of system updates on the Android ecosystem, this could be an even bigger problem. </edit> I believe disabling old TLS versions is the right thing, but not until large parties such as Microsoft and Google decide to take the first step if you still want your server to receive any email.

A lot of MTAs are improperly configured. There's still a lot of plain text email sent across the Internet. The secure mail servers often have trouble connecting to anything with a TLS version higher than 1.0 (if even that). Many mail servers also don't have a valid server certificate (self-signed, expired or even from the wrong domain). In my opinion, the email ecosystem is hopeless with regards to TLS security. Gmail started showing red padlocks for plaintext or insecurely sent emails a while back and I still see the red pad lock to this day. Bexause of this, disabling old TLS versions could make your server unreachable for large parts of the Internet or have servers fall back to plain text if they're improperly configured. Nobody wants to be that one company that can't receive your grandma's emails so everybody just keeps accepting improper configuration. Another problem is that a lot of MDA servers share their TLS config with the MTA side. I know from experience (worked at a small company that upgraded their email servers to TLS 1.2, at least on the MDA side) that old Microsoft mail clients (Office 2007 and lower, Windows Live Mail 2012) have trouble with TLS 1.2, especially on older Windows versions. Although these clients have all been deprecated for a long time, a lot of users with few tech skills still use them because that's what their PC was set up with years ago when they bought it, or because they don't want to waste their time learning how to deal with a new UI (you can see this with a lot of elderly people). For programs that use the Windows 7 TLS libraries TLS 1.2 is even disabled by default in Windows 7 because at the time Windows 7 launched, other implementations had major bugs. It can be enabled using a registry key though. This includes Office 2010, which still gets security fixes from Microsoft. So, if a large company would disable TLS 1.0/1.1 on their MTAs it might get a large amount of customer support calls from their least technical customer base. You can tell your customers that their program is out of date and that their program is the reason they're getting errors, but in the end the customer will still blame you for "breaking their mail program". Aside from a massive blow to a company's reputation, this would also overload the customer support desk and cost a lot of man hours. <edit> Actually, I've seen the built in mail app for Samsung smart phones fail on TLS 1.2 for Android versions up to Android 8. Other Android vendors generally have trouble up to Android 5/6. With the lack of system updates on the Android ecosystem, this could be an even bigger problem. </edit> I believe disabling old TLS versions is the right thing, but not until large parties such as Microsoft and Google decide to take the first step if you still want your server to receive any email.