78/100 SECURITY SCORE

Certificate Information

Subject
CN=gitbook.io
Issuer
C=US, O=Google Trust Services, CN=WE1
Valid From
September 25, 2025
Valid Until
December 24, 2025 47 days
Public Key
ECDSA 256 bit (P-256) Adequate
Signature Algorithm
ECDSA-SHA256
SHA-256 Fingerprint
8C:B1:5D:2E:76:0E:C4:B3:2B:12:2E:B4:55:9E:3A:08:77:5D:26:46:7C:44:1B:BC:17:C3:A4:BD:1B:56:E6:E2
Alternative Names

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
Configured (Restricts certificate issuance)
Current Issuer
Authorized (Matches CAA policy)
Recommendations
  • Consider using critical flag (flags=128) for stricter CAA enforcement
  • Consider adding 'iodef' records to receive notifications about unauthorized certificate issuance attempts
  • Consider adding 'issuewild' records to control wildcard certificate issuance

Subject Alternative Names

2 domains