Avast WEBforum

Consumer Products => Avast Free Antivirus / Premium Security (legacy Pro Antivirus, Internet Security, Premier) => Topic started by: yemyslf on March 06, 2019, 03:32:43 PM

Title: Web Shield blocking a large amount ofwebsites
Post by: yemyslf on March 06, 2019, 03:32:43 PM

I'm experiencing issues with Avast blocking websites and some of the PCs I support. The reason for the block is url:blacklist and the notification states it was blocked by the web shield.  Adding the website to the exceptions list or even turning off the web shield has no impact and it continues to notify me of the blocked traffic. There is a mixture of different Avast versions and products ranging from Avast Free 19.2.2364, Avast Internet Security 19.2.2364, and even one running Avast Free 18.4084.409.

These PCs are all running Zscaler which essentially acts like a Proxy server and forwards all requests to their cloud.  On most PCs the URL being blocked is www.zscaler.com:80 but we've also seen other urls that are known to be safe, for example: http://update.avastbrowser.com:443.  As Avast is blocking this initial connection to Zscaler, traffic is not being forwarded properly.

I suspect that Avast doesn't like something in how Zscaler is forwarding web traffic but don't have any evidence to back this up. Unfortunately, I've been unable to reproduce this issue on any test devices so I'm wondering if a previous version or signature of Avast introduced this issue. We first started seeing this on 2/13/19.  We've tried updating the impacted devices and also tried a repair install but these didn't resolve the problem. 

Has anyone else experienced something similar?

Title: Re: Web Shield blocking a large amount ofwebsites
Post by: LukasJ on March 06, 2019, 03:54:48 PM

Hi,
Detection will be fixed in next update.

Regards
Lukas

Title: Re: Web Shield blocking a large amount ofwebsites
Post by: yemyslf on March 07, 2019, 03:28:53 AM

Thanks Lukas. When will this release be? Do you have any more information on what is impacted specifically(is it proxied traffic?) and what versions are impacted? Curious why I haven't been able to reproduce and why were aren't seeing it on all devices with Avast installed.

Title: Re: Web Shield blocking a large amount ofwebsites
Post by: bob3160 on March 09, 2019, 11:01:37 PM

Quote from: yemyslf on March 07, 2019, 03:28:53 AM

Thanks Lukas. When will this release be? Do you have any more information on what is impacted specifically(is it proxied traffic?) and what versions are impacted? Curious why I haven't been able to reproduce and why were aren't seeing it on all devices with Avast installed.

Update expected on Monday.

Title: Re: Web Shield blocking a large amount ofwebsites
Post by: james.gunn on April 19, 2019, 03:25:54 PM

I'm still experiencing this problem - has the update been released ?

BWs
James

Title: Re: Web Shield blocking a large amount ofwebsites
Post by: bob3160 on April 19, 2019, 03:36:52 PM

Quote from: james.gunn on April 19, 2019, 03:25:54 PM

I'm still experiencing this problem - has the update been released ?

BWs
James

Are you running the latest version ???
https://forum.avast.com/index.php?topic=226462.0