Avast blocking public WiFi?

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Searched the forum but didn't seem to find a topic covering this ...

I can't really say if I've tried to connect to a public WiFi network which should prompt with an "EULA" dialog since I installed Avast on my Mac, but I've found that I cannot do so.  I suspect it might be Avast because in the system log are messages like this:

Apr 20 13:24:38 <computer name> com.avast.service[592]: wifiguard_callback: Detected unsecured WiFi.

I don't know if this is just a warning and the problem is elsewhere, or an indication that Avast actively blocked this action.  I don't see any configuration setting in Avast which might allow me to change this, and disabling web shield didn't seem to make a difference.  My next step is to uninstall Avast to see if that fixes it, but thought I'd try posting here first.

Is the log message an indication that the network connection *is* being blocked, and if so, is there a configuration setting to change that?  Thanks in advance.

Note: macOS version is 10.12.4, and Avast is 12.6.

[lukas.hasik]

Avast Mac Security shouldn't block any WiFi networks. If it does then it's a bug More details welcome!
Help>Avast Technical Support>Generate support package - will send us logs that might help to analyze it.

[.: Mac :.]

Recent versions DO prompt you when connecting to public unsecured WiFi with a small box to promote the SecureLine VPN Product, however this does not in any way block the connection.

[REDACTED]

Avast Mac Security shouldn't block any WiFi networks. If it does then it's a bug More details welcome!
Help>Avast Technical Support>Generate support package - will send us logs that might help to analyze it.

I started to do this and then, after it seemed to complete, realized it was probably a moot point as I was not connected to any network for it to be uploaded (which I assume is how it works?).    As I've never used this before, I presumed that I needed to be in the middle of the problem (connected to a public WiFi but not getting the EULA) at the time I generate the support package.

But, Avast does seem to be a contributing issue because, taking the brute force approach, I uninstalled Avast, rebooted, and was successfully prompted by the WiFi network with the "EULA" dialog and am now connected and working.

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To clarify, it doesn't seem to be blocking the actual connection to the network, because the indicator in the status bar shows there is a connection.  But I do not get the "EULA" prompt which I presume is needed by the network to "authorize" my using it, and uninstalling Avast seems to have removed that issue. 

Note that even with Avast installed, I was able to connect to both traditional password-protected networks and to those which "authorized" use by vectoring your initial browser request to a "you must accept these terms and conditions to go any further" web page.

[.: Mac :.]

If you disable the Web Shield does the issue still occur? Web Shield does a man in the middle style attack to be able to decrypt SSL/TLS traffic for scanning so the issue could be there.

[tumic]

All the "WiFi login pages" do work only for HTTP "by definition"*, so Avast's SSL scanning should not be the issue here.

* you can't redirect HTTPS to HTTP or to a different HTTPS URL on the "WiFi login portal" - this would be detected by the browser as MITM.

[REDACTED]

If you disable the Web Shield does the issue still occur? Web Shield does a man in the middle style attack to be able to decrypt SSL/TLS traffic for scanning so the issue could be there.

Yes, this is one of the first things I tried, to no effect.

I spoke with a colleague in my company's IT networking group (because another place this failed was on our corporate guest WiFi network).  His understanding is that once the wireless driver connects, it does an HTTP "phone home" (for Mac, he presumes to apple.com) to verify that it can "see the internet", and our wireless LAN controller, when it sees it's a device it doesn't yet recognize, redirects that HTTP request to one with our "EULA" (terms you agree to for using our guest wireless service), and that the pop-up dialog then presented is not your default browser, but a browser-like interface that's part of the OS' wireless software (similar to how it works on your smart phone).  He suspects the other public WiFi networks which were failing probably work similarly, but I admittedly don't know enough about this topic to understand how this differs from networks which prompt you after you open your browser and try to go to the first web page (which I think worked fine with Avast installed).

[DoctorDunc]

Hi.  I know it's a bit of an old thread to be reviving but the same seems to be happening to me.  From what I read the only fix seems to be uninstall Avast so one last chance!  It's an old phone (android 5.0).  I mention this because my brother on a relatively new phone running Avast (he thinks anyway) can log in to NHS wifi but I'm sat next to him and can't.  Neither have I been able to access public council wifi.  It happened again this morning but there was nothing in the activity log and there doesn't seem to be a safe site log.

Thanks, Duncan

[DavidR]

Not only is it an old thread, it is also for Avast Mac Security and you using the Avast Mobile Security for Android product, so this should go in the Avast Mobile Security for Android sub-forum.

There if you can give more details on what version and build number of the Avast Mobile Security for Android that you are using.  You may even find a related topic there.

I'm not even sure if you can use the latest version Avast Mobile Security for Android with Android 5.0