Open
Cached
·
just now
89/100
SECURITY SCORE
Certificate Information
Subject
CN=slack.com
Issuer
C=US, O=Let's Encrypt, CN=R13
Valid From
September 30, 2025
Valid Until
December 29, 2025
56 days
Public Key
RSA
2048 bit
Adequate
Signature Algorithm
SHA256-RSA
SHA-256 Fingerprint
83:AB:2A:75:4F:45:D9:20:A7:DE:7D:8C:1E:D6:FE:C5:76:5B:C9:E3:B3:04:D2:F0:7D:D0:8B:F1:22:8F:D8:FC
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
Excellent
max-age=31536000; includeSubDomains; preload
Content-Security-Policy
Missing
Not configured
X-Frame-Options
Good
SAMEORIGIN
X-Content-Type-Options
Missing
Not configured
Referrer-Policy
Good
no-referrer
Permissions-Policy
Missing
Not configured
Recommendations
- • Add Content-Security-Policy header to prevent XSS attacks
- • Add X-Content-Type-Options: nosniff
- • 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)
Authorized CAs
digicert.com
; account=455b15ed272bed097725c6ea50e89921fc57379c5338a29305c05771df65fff1
letsencrypt.org
; accounturi=https://acme-v02.api.letsencrypt.org/acme/acct/1532134906
Incident Reporting
mailto:[email protected]
Recommendations
- • Consider using critical flag (flags=128) for stricter CAA enforcement
- • Consider adding 'issuewild' records to control wildcard certificate issuance