How to Check if a Website is Safe Before You Click

1. Inspect the URL Carefully

• Is it HTTPS? (padlock icon in browser)
• Does the domain match exactly? paypa1.com ≠ paypal.com
• Suspicious TLDs: .tk, .ml, .gq, .cf are frequently used for phishing
• Unusually long domains: paypal-secure-login-verify.malicious.com

2. Check the SSL Certificate

# View certificate details from command line
openssl s_client -connect suspicious-site.com:443 2>/dev/null \
  | openssl x509 -text -noout

# Quick check — issuer and expiry
openssl s_client -connect suspicious-site.com:443 2>/dev/null \
  | openssl x509 -issuer -dates -noout

# Is the cert still valid?
echo | openssl s_client -connect suspicious-site.com:443 2>/dev/null \
  | openssl x509 -checkend 0
# Exit code 0 = valid, 1 = expired

3. Check Security Headers

# Check all security-relevant headers
curl -sI https://suspicious-site.com | grep -iE \
  "strict-transport|content-security|x-frame|x-content-type|referrer-policy"

# What good headers look like:
# Strict-Transport-Security: max-age=31536000; includeSubDomains
# Content-Security-Policy: default-src 'self'
# X-Frame-Options: DENY
# X-Content-Type-Options: nosniff
# Referrer-Policy: strict-origin-when-cross-origin

4. Check Against Threat Feeds

# URLhaus (malware URL database)
curl -s "https://urlhaus-api.abuse.ch/v1/url/" \
  -d "url=https://suspicious-site.com"

# Check domain age (recently registered = red flag)
whois suspicious-site.com | grep -iE "creation date|registered"

# Check if domain is in Spamhaus DNSBL
host suspicious-site.com zen.spamhaus.org

5. Check for Mixed Content

# Find HTTP resources on an HTTPS page (security risk)
curl -s https://suspicious-site.com | grep -oP 'src="http://[^"]*"'
curl -s https://suspicious-site.com | grep -oP 'href="http://[^"]*"'

External Resources

• Qualys SSL Labs — Deep SSL/TLS analysis
• Mozilla Observatory — Security headers scanner
• SecurityHeaders.com
• VirusTotal — Multi-engine URL scanner