Virus alerts - STARTTLS request missing when connecting to mail server?

Avast Free Antivirus / Premium Security
1

SMTP settings for virus alerts in my avast! free antivirus 6.0.1000 are configured to use authentication. My email server (postfix) receiving the alerts is configured to require TLS before offering authorization (smtpd_tls_auth_only = yes), which is a quite common setting to avoid sending clear text password via an unencrypted channel.

When I am testing the setup using Settings->Virus Alerts->Alert Targets->Test the mail is accepted by my mail server. When an alert is triggered e.g. during a file scan, the mail is not accepted.

The mail log reveals the reason for this behaviour. In the first case avast! issues a STARTTLS command (line 00000022) whereas in a regularly triggered alert during file scanning avast! even reverts to ordinary SMTP (line 00000051)

Is this an intended behaviour or am I missing something?

Thanks and best regards,
Klemens

test using Settings->Virus Alerts->Alert Targets->Test :
00000012 < EHLO w431
00000013 > 250-mail.int.XXXXXX.de
00000014 > 250-PIPELINING
00000015 > 250-SIZE 10485760
00000016 > 250-VRFY
00000017 > 250-ETRN
00000018 > 250-STARTTLS
00000019 > 250-ENHANCEDSTATUSCODES
00000020 > 250-8BITMIME
00000021 > 250 DSN
00000022 < STARTTLS
00000023 > 220 2.0.0 Ready to start TLS
00000024 < EHLO w431
00000025 > 250-mail.int.XXXXXX.de
00000026 > 250-PIPELINING
00000027 > 250-SIZE 10485760
00000028 > 250-VRFY
00000029 > 250-ETRN
00000030 > 250-AUTH PLAIN LOGIN
00000031 > 250-ENHANCEDSTATUSCODES
00000032 > 250-8BITMIME
00000033 > 250 DSN
00000034 < AUTH PLAIN
00000035 > 334
00000036 < XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
00000037 > 235 2.0.0 Authentication successful
00000038 < MAIL FROM:

virus alert triggered during a file scan:
00000041 < EHLO w431
00000042 > 250-mail.int.XXXXXX.de
00000043 > 250-PIPELINING
00000044 > 250-SIZE 10485760
00000045 > 250-VRFY
00000046 > 250-ETRN
00000047 > 250-STARTTLS
00000048 > 250-ENHANCEDSTATUSCODES
00000049 > 250-8BITMIME
00000050 > 250 DSN
00000051 < HELO w431
00000052 > 250 mail.int.XXXXXX.de
00000053 < MAIL FROM:

2

Is any Avast developer around here, who could help me with this issue?
I suppose it could be easily fixed, if my attempt to analyse the problem would be provided to the development team.

Many thanks,
Klemens

3

This section is slightly confusing, since the test email that is sent uses the mail shield, so it can initiate SSL/TLS, but the actual alert email doesn’t use the mail shield, so it doesn’t work. It needs an account that doesn’t require SSL.

FWIW I haven’t managed to get this to work either…

4

Thanks, actually the mail shield seems to be the reason for the different behaviour. When I disable it, the alert email can’t be delivered either, if TLS is required. (Interestingly it isn’t enough to disable/enable the mail shield - additionally a reboot is necessary)

So in the end it is currently not possible to use virus alerts in conjunction with a mail server that requires TLS before authorization.

Because the latter is considered a secure setup, I would appreciate if it could be supported in a future release.