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I received a spam text message and interrogated the domain name:

$ openssl s_client -servername https://example.com -connect example.com:443

What I want to know, is how likely it is that I should see the following

write:errno=0
no peer certificate available
No client certificate CA names sent
SSL handshake has read 0 bytes and
written 301 bytes
Verification: OK
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)

Cipher = none? That seems very suspicious to me. As far as I know, the encryption aspect is the only part that actually secures against manipulation. Am I talking to who I think I'm talking to?

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  • Welcome to the community. I would assume that there is no SSL certificate meaning that the connection is unencrypted and over HTTP. That doesn't mean much I think, even if most serious websites use HTTPS (meaning uses SSL certificates). Mar 15, 2023 at 20:14
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    The first line of the session display for a good connection is "New, {protocol}, Cipher is {ciphersuite}" -- thus that first "(NONE)" before Cipher means there was no handshake (as Steffen also confirms from "handshake has read 0") and since the ciphersuite is a result of the handshake with no handshake it is completely impossible for there to be a ciphersuite. This is like if you have no children then you can't fill in their age(s) on your tax return because people who don't exist don't have an age. Mar 15, 2023 at 23:41

1 Answer 1

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There are likely more messages which you did not include in your question. But obviously the server did not even reply, just closed the connection:

write:errno=0
...
SSL handshake has read 0 bytes and
written 301 bytes

This means there was no successful TLS handshake.

Apart from that the -servername argument should only be the hostname, not a URL. I.e. instead of

$ openssl s_client -servername https://dom.ain -connect dom.ain:443

use

$ openssl s_client -servername dom.ain -connect dom.ain:443
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  • You are correct. I had an omission of: (line #1: "CONNECTED(00000003)") Mar 15, 2023 at 20:14

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