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Dovecot SSL Errors in Freshly Provisioned WHM VPS

Comments

7 comments

  • cPanelMichael
    Hello :) Did you modify any of the SSL Cipher settings for Dovecot before noticing this error message? Thank you.
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  • gn0s1s
    No, as far as I am aware nothing was modified. But it appears that the fix above has not worked in this instance, since I got this again today.
    **Unmatched Entries** dovecot: imap-login: Error: SSL: Stacked error: error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol: 2 Time(s) dovecot: master: Dovecot v2.2.21 (5345f22) starting up for imap, pop3 (core dumps disabled): 1 Time(s) dovecot: pop3-login: Error: SSL: Stacked error: error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol: 2 Time(s)
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  • gn0s1s
    Some more unmatched entries today. Would love to get to the bottom of why they keep recurring.
    dovecot: pop3-login: Error: SSL: Stacked error: error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol: 3 Time(s) dovecot: pop3-login: Error: SSL: Stacked error: error:1408A0C1:SSL routines:SSL3_GET_CLIENT_HELLO:no shared cipher: 42 Time(s) dovecot: pop3-login: Error: SSL: Stacked error: error:1408A10B:SSL routines:SSL3_GET_CLIENT_HELLO:wrong version number: 20 Time(s)
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  • cPanelMichael
    Please post the output from the following commands:
    grep openssl_options /etc/exim.conf grep ssl_protocols /etc/dovecot/dovecot.conf
    Thank you.
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  • gn0s1s
    Please post the output from the following commands:
    grep openssl_options /etc/exim.conf grep ssl_protocols /etc/dovecot/dovecot.conf

    Here it is.
    root@obscured [~]# grep openssl_options /etc/exim.conf openssl_options = +no_sslv2 +no_sslv3 root@obscured [~]# grep ssl_protocols /etc/dovecot/dovecot.conf ssl_protocols = !SSLv2 !SSLv3 root@obscured [~]#
    So from what I can gather these are attempts by someone to connect using an old protocol that's turned off (and turned off with good reason, if my reading is right). Is this correct?
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  • cPanelMichael
    So from what I can gather these are attempts by someone to connect using an old protocol that's turned off (and turned off with good reason, if my reading is right). Is this correct?

    Yes, you are using the default entries, and the messages suggest the person connecting is using an unsupported protocol. This can indicate the user attempting to make the connection needs to update their email client to the latest version. Thank you.
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  • gn0s1s
    Yes, you are using the default entries, and the messages suggest the person connecting is using an unsupported protocol. This can indicate the user attempting to make the connection needs to update their email client to the latest version.

    There are no sites set up on this VPS yet and in fact, no domain or hostname associated with it, so there should be no users trying to access it with any protocols. I'm just trying to figure out processes for dealing with intrusion attempts and false positives in security scans before I start moving actual sites over. It seems like someone is probably using a script to move through IP ranges and trying to exploit a POODLE vulnerability using these protocols. They're gonna get the banhammer. :-)
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