Google Chrome attacker or wifi playing up?

[stucky]

I've been having trouble with Google Chrome and avast for the past few weeks. I have discovered Avast has been replacing certificates with their own. I tested this out with IE and Avast does the same. I removed Avast and reinstalled a customised version. Since then no problem from them.
But I am still getting the message from Google Chrome: Your connection is not private. Attackers might be trying to steal your information from www.xxxx.com.
www.xxxx.com normally uses encryption to protect your information. When Google Chrome tried to connect to www.xxxx.com this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be www.xxxx.com, or a Wi-Fi sign in screen has interrupted the connection. Your information is still secure because Google Chrome stopped the connection before any data was exchanged.

Date and time are correct. There's no extensions in my browser but google's own. Have cleared browsing history, cache and cookies. Have tried using a different AV (Avira) but Google chrome still give me this message. When using full Avast, this message would appear at different times. Example, logging into twitter but not every time I log into twitter. No consistency when it would appear.

I have a theory but I don't know if this is possible... I am on the internet, I don't know that my router has lost connection, I try to go to a websites THEN that Google Chrome message appears. My wifi comes back on then no more messages for all the time I am surfing. Since installing a customised Avast, this is the only time this message appears.

Could it be that Google Chrome thinks I am under attack because the wifi was lost before the webpage I was going to had loaded?

 

[Calculagator]

When you see the error in Chrome, look for a link for more information. You can also click the little lock/page icon in the address bar. These should list information about the certificate that is being used to secure your connection and what specific problems Chrome thinks the certificate has. This information will tell you the source of the problem. If you visit google.com and the certificate is owned by avast, then avast is still causing problems. If you need more help, post the content of the error messages you are getting.

 

[stucky]

Today Avast showed up again after not showing for a few days. Unknown to me I had lost wi-fi and Avast messages appeared saying the certificate has expired. I have since uninstalled Avast and have chosen Avira instead.
Google Chrome hasn't given me the message Your connection is not private. Attackers might be trying to steal your information. Not since I last posted here anyway.
I guess only time will tell but it's a pain because it doesn't happen that often I could be fine or it could pop up days later.

Is it safe to do online banking in the meantime? I've got stuff to do but don't want to if there is a security risk.

If Google Chrome does give that message again I will check out the certificate like you have said and report back here.

 

[u2desire420]

I would suspect infection but I would also check what Chrome extensions you have installed.

 

[u2desire420]

Your problem is not Avast. I have been using Avast for 13 years and have never had the problem you describe so you have malware. Go to Avast forums and ask for help in the virus and worms section follow the steps https/forum.avast.com/index.php?topic=53253.0 than start your own thread. Chances are the malware is still on your computer and Avira (over bloated piece of crap IMHO) isn't picking it up.

 

[u2desire420]

I should also add that it could also be a router infection. I would reflash firmware to the latest version or better yet use DD-WRT on it.