Author Topic: Avast replaces SSL certificates in Firefox  (Read 7548 times)

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Offline Djfe

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Avast replaces SSL certificates in Firefox
« on: November 25, 2014, 09:43:03 PM »
Why does Avast replace/change the certificates of websites before they arrive?

I mean of course I want to allow Avast to check my mails, but it isn't supposed to replace certificates by Facebook and other popular websites...
It should only replace stuff in Thunderbird, Windows Live Mail, Outlook etc.

I'm using Firefox 33.1 on Win7 64bit
Avast 2015
I uninstalled the browser extension, because I prefer WOT.

Offline Eddy

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Re: Avast replaces SSL certificates in Firefox
« Reply #1 on: November 25, 2014, 09:53:41 PM »
You are mixing up things.
There is the email scanner and the web (https) scanner.
For avast to be able to scan https it needs that certificate.

REDACTED

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Re: Avast replaces SSL certificates in Firefox
« Reply #2 on: November 30, 2014, 06:48:12 PM »
Hi Eddy,
the problem is that avast is currently blocking the use of some sites that are accessed via https as it puts an self created cert into the connection and the browser (Chrome+Firefox) throws an error.
Some examples:
web.de uses (without avast) a cert which is issued by T-Systems International GmbH.
with avast enabled I get "generated by avast! antivirus for untrusted server certificates"
Firefox tells me that this certificate couldn't be verified as the issuer is unkown


same for leo.org .

For  freenet.de login it gives:
(auth.freenet.de verwendet ein ungültiges Sicherheitszertifikat. Dem Zertifikat wird nicht vertraut, weil keine Zertifikatsausstellerkette angegeben wurde. (Fehlercode: sec_error_unknown_issuer))

Once disabled the web shield can't be enabled again without a reboot.

I've reinstalled avast and after the installation of version 10.0.2206.692 all works as expected. Then avast come up with an application update to version 10.0.2208 and it doesn't work anymore.

I'm going to disable avast until a new update. hopefully it will fix these problems. I've tried to open a support ticket with these informations but I'm not sure if it was transmitted as the browser jumped back to the first support page and I didn't got a confirmation mail.