DNS Gurus

SSL Verification Bypassed

The server's SSL certificate could not be verified. The analysis was completed using insecure mode. Data may be less reliable.

Reason:

Hostname Mismatch - certificate is issued for *.groupon.ae, *.groupon.be, *.groupon.ca, *.groupon.co.nz, *.groupon.co.uk, *.groupon.com, *.groupon.com.au, *.groupon.de, *.groupon.es, not for assets1.grouponcdn.com

Cached · just now
72/100 SECURITY SCORE

Certificate Information

Subject
CN=*.groupon.com
Issuer
C=US, O=Let's Encrypt, CN=R13
Valid From
November 19, 2025
Valid Until
February 17, 2026 22 days
Public Key
RSA 2048 bit Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
20:16:A8:93:37:35:79:F9:2C:B1:0A:82:AE:50:18:88:46:B3:EF:F7:43:AC:4E:C1:43:FF:B6:A6:3E:8D:AE:05
Alternative Names
46 domains

Security Configuration

TLS Protocols
TLS 1.2 TLS 1.3
Forward Secrecy
Supported (Modern clients use PFS)

HTTP Security Headers

Status
Strict-Transport-Security
Missing
Not configured
Content-Security-Policy
Missing
Not configured
X-Frame-Options
Missing
Not configured
X-Content-Type-Options
Missing
Not configured
Referrer-Policy
Missing
Not configured
Permissions-Policy
Missing
Not configured
Recommendations
  • • Add Strict-Transport-Security header with max-age of at least 1 year
  • • Add Content-Security-Policy header to prevent XSS attacks
  • • Add X-Frame-Options: DENY or SAMEORIGIN to prevent clickjacking
  • • Add X-Content-Type-Options: nosniff
  • • Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)
  • • Consider adding Permissions-Policy to control browser features

CAA Records (Certificate Authority Authorization)

CAA Records
Not Configured (Any CA can issue certificates)
CAA Issues
  • • No CAA records configured - any CA can issue certificates
Recommendations
  • • Implement CAA records to restrict which CAs can issue certificates for your domain
  • • This adds an extra layer of security against unauthorized certificate issuance
  • • Example: Add CAA record 'example.com. CAA 0 issue "letsencrypt.org"'
  • • Consider adding 'iodef' record to receive security incident reports