Browser Blacklists: Fixing Certificate Issues

TL;DR

Browsers use blacklists to warn you about dodgy websites and invalid security certificates. Sometimes legitimate sites get blocked by mistake, or your system clock is wrong causing certificate validation failures. This guide explains how to check if a site is blacklisted, fix common problems with your browser, and update your system time.

1. Checking if a Site is Blacklisted

Several free tools can tell you if a website is on common blocklists. Here are a few:

• VirusTotal: https://www.virustotal.com/gui/domain/example.com (Replace example.com with the website you’re checking).
• Google Safe Browsing: https://transparencyreport.google.com/safe-browsing/search
• URLVoid: https://www.urlvoid.com/

If a site is listed, it usually means it’s been flagged for malicious activity (phishing, malware etc.). Contact the website owner to report the issue.

2. Fixing Browser Certificate Errors

Browser certificate errors often happen because of:

• Incorrect System Time: Certificates are only valid during a specific date range.
• Outdated Root Certificates: Browsers rely on root certificates to verify website identities.
• Corrupted Browser Cache: Sometimes old, incorrect data causes problems.

2.1 Check Your System Time

Make sure your computer’s date and time are correct.

• Windows: Right-click the clock in the taskbar → Adjust date/time → Ensure “Set time automatically” is turned on.
• macOS: System Preferences → Date & Time → Enable “Set date and time automatically”.

If automatic setting doesn’t work, manually set the correct date and time.

2.2 Update Your Browser

Outdated browsers often have outdated root certificates. Update to the latest version:

• Chrome: Click the three dots → Help → About Google Chrome. It will automatically check for updates.
• Firefox: Click the three lines → Help → About Firefox. It will automatically check for updates.
• Edge: Click the three dots → Help and feedback → About Microsoft Edge. It will automatically check for updates.

2.3 Clear Browser Cache

Clearing your browser cache can remove corrupted data.

• Chrome: Click the three dots → More tools → Clear browsing data. Select “Cached images and files” and click “Clear data”.
• Firefox: Click the three lines → Settings → Privacy & Security → Cookies and Site Data → Clear Data. Select “Cached Web Content” and click “Clear”.
• Edge: Click the three dots → Settings → Privacy, search, and services → Choose what to clear → Select “Cached images and files” and click “Clear now”.

3. Understanding the Symantec-Google Certification Debacle

In 2015/2016, Google removed trust from several Symantec certificates due to mis-issuance practices. This caused widespread problems for websites using those certificates.

• What happened: Symantec incorrectly issued certificates for domains they didn’t control.
• Google’s response: Gradually removed trust in affected certificates, starting with Extended Validation (EV) certificates.
• Impact: Websites using these certificates showed security warnings to users.

Most browsers have since updated their root stores to address this issue. However, if you’re still encountering problems related to Symantec certificates, ensure your browser is fully up-to-date (see section 2.2).

4. Advanced Troubleshooting

If the above steps don’t fix the problem:

• Check Your Antivirus/Firewall: Some security software can interfere with certificate validation. Temporarily disable it to see if that resolves the issue (be careful when doing this!).
• Reset Browser Settings: As a last resort, you can reset your browser to its default settings. This will remove all extensions and customizations.
  Warning: This will delete your bookmarks and saved passwords, so back them up first!