SSL Certificate Analysis for e.developer.yahoo.co.jp - Security Grade & TLS Configuration

Certificate Information

Subject

C=JP, ST=Tokyo, L=Chiyoda-ku, O=LY Corporation, CN=gw01.yahoo.co.jp

Issuer

C=JP, O=Cybertrust Japan Co., Ltd., CN=Cybertrust Japan SureServer CA G4

Valid From

November 19, 2025

Valid Until

December 18, 2026 334 days

Public Key

RSA 2048 bit Adequate

Signature Algorithm

SHA256-RSA

SHA-256 Fingerprint

36:C0:83:43:45:99:9E:A2:4D:AE:D9:34:96:22:CA:05:53:31:CC:B2:28:B8:CD:43:5E:06:38:6B:C3:18:16:3E

Alternative Names

74 domains

Security Configuration

TLS Protocols

TLS 1.2

Forward Secrecy

Limited (Check cipher configuration)

Warnings

• TLS 1.3 is not supported (recommended)

HTTP Security Headers

Status

Strict-Transport-Security

Good

max-age=31536000 ; includeSubDomains

Content-Security-Policy

Missing

Not configured

X-Frame-Options

Excellent

DENY

X-Content-Type-Options

Good

nosniff

Referrer-Policy

Missing

Not configured

Permissions-Policy

Present

unload=()

Recommendations

• Consider adding 'preload' to HSTS for maximum security
• Add Content-Security-Policy header to prevent XSS attacks
• Add Referrer-Policy header (recommended: strict-origin-when-cross-origin)

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