Hotmail Certificate & Connection Security

TL;DR

This guide helps you check if your connection to Hotmail (now Outlook.com) is secure and that the certificate used by Microsoft is valid. We’ll cover how to verify this in your browser, using online tools, and understanding common errors.

Checking Certificate Validity

1. Check Your Browser’s Security Indicator: Most browsers show a padlock icon in the address bar when connected securely (HTTPS). Click it for details.
2. View Certificate Details:
   • Chrome/Edge: Click the padlock > Connection is secure > Certificate is valid. Then click on ‘Certificate’.
   • Firefox: Click the padlock > Connection Secure > More Information > View Certificate.
3. Verify Certificate Information: Look for these key details:
   • Issued To: Should be Microsoft Corporation or a related entity (e.g., outlook.com).
   • Issued By: A trusted Certificate Authority (CA) like DigiCert, Sectigo, or Let’s Encrypt. Don’t trust certificates issued by unknown CAs.
   • Validity Period: The certificate should be within its ‘Valid from’ and ‘Valid to’ dates. Expired certificates are a major security risk.

Using Online SSL Checker Tools

These tools provide detailed analysis of the website’s SSL/TLS certificate.

1. SSL Labs: https://www.ssllabs.com/ssltest/ Enter outlook.com and run the test. Pay attention to the overall rating (A+ is best) and any warnings or errors reported.
2. DigiCert SSL Installation Diagnostics Tool: https://www.digicert.com/help/ This tool checks for common certificate installation issues.

Understanding Common Errors

1. “Your connection is not private” / “NET::ERR_CERT_AUTHORITY_INVALID”: This usually means:
   • The certificate has expired.
   • The certificate doesn’t match the website address (e.g., a certificate for example.com on outlook.com).
   • Your computer doesn’t trust the Certificate Authority that issued the certificate. This can happen if your root certificates are outdated.
2. Expired Certificate: If the certificate is expired, Microsoft should automatically renew it. However, sometimes browser caches cause issues. Try:
   • Clearing your browser cache and cookies.
   • Trying a different browser.
3. Root Certificate Issues: Update your operating system’s root certificates.
   • Windows: Windows Update usually handles this automatically. You can also manually update via

     certutil -urlcache * delete

     in an elevated command prompt, followed by restarting your computer.

   • macOS: macOS updates root certificates as part of system updates.
4. Man-in-the-Middle (MITM) Attack: If you suspect a MITM attack, do not enter any sensitive information on the website. Contact Microsoft support immediately.

Ensuring Connection Security

Always ensure you are using HTTPS when accessing Hotmail/Outlook.com.

1. Check the Address Bar: The address should start with https://, not http://.
2. Avoid Public Wi-Fi: Public Wi-Fi networks are often insecure. Use a VPN when connecting to public Wi-Fi.
3. Keep Your Browser Updated: Newer browsers have better security features and can detect more threats.