Avast recently started blocking our application

We have an application that our clients would like to use for their daily work, but recently Avast (and other antivirus software) started doing some rather nasty things.

By which I mean silently taking files (we have a few .exe and a few .dll files that we need), or silently blocking the main exe from running at all. Keyword here being: silently.

There’s no pop-up that it had found a virus. The files work fine with Avast disabled. The files are detected to be clean when Avast is asked to check the directory.

How about telling us what the problem is instead of silently doing stuff?

What OS/SP ?
What exact version of avast ?
What VPS version ?
Any other security (related) software installed ?

Have a look in the log files to see if there is any information.

Upload and test your program here www.virustotal.com if tested before, click rescan for a fresh result
Post link to scan result here

https://www.virustotal.com/en/file/6cbbff668b7f7ba94c9d774342908dee7f961abf9a9b3d93262e66d5d8899ccf/analysis/1449656215/ seems all fine to me.

We’ll look into this more precisely the next time we have access to the machine. No idea about the avast client’s version, but the virus definitions are the newest. My coworker said it was win8 or win10.

submit a ticket here https://support.avast.com/support/tickets/new

you may give link to this topic

Thanks, submitted.

Please let us know if you have received word from avast.
The answer may help others.

I have, we have yet to investigate a few more things though, so I cannot provide more detailed answer yet.

No need to rush with the risk overlooking things.
Take the time that is needed.

Well, sorry to necro this topic and sorry for not checking back for a long time, but here it is.

Avast Support recommended upgrading to a newer version of Avast, and that of course didn’t change anything. In fact, the issue is still present with more recent builds of our software, with fresh and new installs of Avast (and various other common antivirus software). As always, virustotal says it’s perfectly clean: https://www.virustotal.com/en/file/f09b25555d8b37896fb692ff4b87faa5cd1cc91271de9902b1bb12253352db41/analysis/1510310305/

All the files we ship in this thing (it’s an ActiveState self-hosting executable, no installer, it just extracts various dlls and shipped files and executables during run) are also virus-free (and still more often than it’s comfortable, they either get silently blocked from running, or silently quarantined; or when run separately also get sent for analysis and blocked, even though they had been run before from within the main software).

Eg. https://www.virustotal.com/en/file/3f8bb63867ecf5f446cfefcf71a3d5db3fe604c32c0e99c1695336153dd9a75d/analysis/1510310847/

Adding the directory that holds the shipped files to the white list doesn’t help with the default settings of Avast, and we can’t expect all our users to mess around with the antivirus settings.

Avast Support recommended using some Uninstall Tool I had never heard about to uninstall the old Avast and then install a new one — that was kinda strange, but whatever. Windows’ built-in uninstall has always been sufficient.

I’m not sure what else we could do to not trigger heuristics simply due to our software not being used by millions of people.


On my test system (a Windows 7), here’s the current versions of Avast:

  • Avast: 17.7.2314 (Build 17.7.3660.244)
  • Virus definitions: 171110-0

Start a new topic in V&W: https://forum.avast.com/index.php?action=post;board=4

Hello,
use https://www.avast.com/false-positive-file-form.php

Milos

Submitted, thank you!

As you’re a developer, read here…

https://support.avast.com/article/229/
https://support.avast.com/article/228/