I assume Safari is working normally on those sites?
The latest version of avast! Web Shield includes a feature to filter your web connections for potential threats. In order to filter secure sites, it must present a 'fake' certificate for the site to Firefox, so it can be 'in the middle' and read your secure communications. If Firefox is not set up to trust the fake certificates, then you will get warnings for every secure site.
You might want to turn this feature off as a test to see whether the problem goes away.
If that works, but you want to use the feature, you'll need to import Avast's certificate into Firefox's 'Authorities' tab so Firefox accepts its fake certificates (there might be an automated way AVAST intended for you to do this, or you might need to export from IE and then import into Firefox).
Here is some discussion on avast!'s forum about how this is supposed to work: Issues and questions on HTTPS Scanning - Avast Internet 2015
What is HTTPS scanning in Avast Antivirus?
Adding Specific Shield (File System, Mail, or Web) Exception into Avast 2018 On the screenshot above, you can see many items are excluded from the File System Shield scan by default. We haven’t added any of them. Web Shield includes a feature to filter your web connections for potential threats. In order to filter secure sites, it must present a 'fake' certificate for the site to Firefox, so it can be 'in the middle' and read your secure communications.
Web Shield is an additional layer of active protection in Avast Security. It scans data that is transferred when you browse the internet in real-time to prevent malware, such as malicious scripts, from being downloaded and run on your Mac. Avast, a security solution designed to protect your business data and computers from most types of cyberattacks, uses a set of modules to scan various parts of your system. One module, Web Shield. My avast progeam is not running, and won't let me fix or start it from my desktop. Just search your email account for any Avast related emails. You can find the product key in one of them. Ask Your Own Computer Question. It said the web was not. There is no longer a shield in the bottom tool tray. Email & Web Shield: Email shield will prevent you from sending and receiving the malicious email attachments whereas web shield blocks dangerous downloads, and prevents malicious websites from injecting malware to Mac.
HTTPS scanning is a feature of Web Shield in Avast Antivirus and is automatically enabled when Avast is installed. HTTPS scanning decrypts and scans encrypted traffic to detect potential mawlare contained on sites using HTTPS connections.
What is HTTPS?
HTTPS (Hyper Text Transfer Protocol Secure) is a more secure version of the standard HTTP connection. HTTPS adds encryption which prevents others from eavesdropping, and helps ensure that you are connected to the intended server.
For detailed information about HTTPS, refer to the wikipedia page below:
What is the benefit of HTTPS scanning?
While an HTTPS connection ensures that the connection can not be modified by anyone else, it does not guarantee that the content contained on the site is clean. Malware scripts and binaries can be placed into an HTTPS page that appears to be safe. The HTTPS scanning feature prevents you from downloading malicious content from sites secured with an HTTPS connection onto your PC.
Is the HTTPS connection still secure when Avast scans it?
When the Web Shield in Avast Antivirus scans the HTTPS connection, the data being scanned remains encrypted and secure. While HTTPS scanning is in effect, the Web Shield and your browser are on the same PC.
Is all my web traffic sent to the Avast servers?
No, all scanning occurs locally on your PC during the HTTPS connection. No one outside of your PC can read or decipher the connection.
Does Avast scan all HTTPS connections?
When HTTPS scanning is enabled, Avast scans all HTTPS connections for potential malware except for verified sites which have been added to our whitelist. This list primarily contains banking sites. If your bank is not on this list, or you want to exclude a certain site from HTTPS scanning, you can verify the site's security certificate and submit it via email to banks-whitelist@avast.com.
Alternatively, you can disable the HTTPS scanning feature.
How do I disable HTTPS scanning?
While it is recommended to keep HTTPS scanning enabled, you can disable the feature.
- Open the Avast user interface and select
☰Menu ▸ Settings ▸ Protection ▸ Core Shields. - Scroll down to Configure shield settings, click the Web Shield tab.
- Untick the box next to Enable HTTPS scanning.
For detailed instructions, read the following article:
- Avast Premium Security 19.x
- Avast Free Antivirus 19.x
- Avast Omni 1.x
- Avast Premier 19.x
- Avast Internet Security 19.x
- Avast Pro Antivirus 19.x
Mac Mail And Outlook
- Microsoft Windows 10 Home / Pro / Enterprise / Education - 32 / 64-bit
- Microsoft Windows 8.1 / Pro / Enterprise - 32 / 64-bit
- Microsoft Windows 8 / Pro / Enterprise - 32 / 64-bit
- Microsoft Windows 7 Home Basic / Home Premium / Professional / Enterprise / Ultimate - Service Pack 1, 32 / 64-bit