I just requested a CSR from my shared web hosting provider, to generate a certificate which I will send back to them to install. (The certificate itself is to be generated properly by an organisation I work for who can provide certificates for our official use.) The hosting company promptly sent me the CSR but also the private key! They even CC'd someone else, and it's in Gmail so Google has presumably already ingested it for advertising purposes.
In my humble opinion this seems like a terrible thing to do. I am about to write back to them rejecting this one, and asking to renew the CSR and this time keep the private key - private.
Before I make a fool of myself, I'd like to confirm that the private key for an "SSL" (TLS) certificate should never leave the server?
I've been working in security-related industries for many years, and used to be a crypto programmer, so I feel I know the topic a little - but I know things change over time.
I have read this related question: What issues arise from sharing a SSL certificate's private key?
Meta Update: I've realised I've written a poor-quality question format for Stack Exchange - as it's now difficult to accept a specific answer. Apologies for that - all answers covered different and equally interesting aspects. I did initially wonder how to word it for that purpose but drew a blank.
Update: I have followed this though with the host and they did "apologise for any inconvenience", promised to keep future private keys "safe" and issued me a new, different CSR. Whether it's generated from the same exposed private key I am currently unsure of. I now also wonder, as it's a shared host, if they've sent me the key for the entire server or if each customer/domain/virtual host gets a key pair.
It's an interesting lesson how all the crypto strength in the world can be rendered null and void by a simple human error. Kevin Mitnik would be nodding.
Update 2: In response to an answer from user @Beau, I have used the following commands to verify the second CSR was generated from a different secret private key.
openssl rsa -noout -modulus -in pk1.txt | openssl md5 openssl req -noout -modulus -in csr1.txt | openssl md5 openssl req -noout -modulus -in csr2.txt | openssl md5
The first two hashes are identical, the third is different. So thats good news.