Security Best Practices

TLS/SSL Security Best Practices

Use Modern TLS Protocols

Chef Automate supports TLS 1.2 and TLS 1.3. For optimal security, use the following configuration:

Recommended Configuration (Production)

[load_balancer.v1.sys.ngx.http]
ssl_protocols = "TLSv1.2 TLSv1.3"
ssl_ciphers = "ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256"
ssl_ciphersuites = "TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256"

This configuration:

• Supports both TLS 1.2 (for legacy clients) and TLS 1.3 (for modern clients)
• Prioritizes strongest ciphers
• Provides forward secrecy with ECDHE key exchange
• Disables weak and deprecated protocols

High Security Configuration (TLS 1.3 Only)

For environments where all clients support TLS 1.3:

[load_balancer.v1.sys.ngx.http]
ssl_protocols = "TLSv1.3"
ssl_ciphersuites = "TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256"

Deprecated and Insecure Protocols

TLS Cipher Selection Guidelines

TLS 1.3 Cipher Suites (Priority Order)

1. TLS_AES_256_GCM_SHA384 (Highest Security)

   • AES-256 encryption with GCM mode
   • 384-bit SHA hash
   • Best for environments requiring maximum security

2. TLS_CHACHA20_POLY1305_SHA256 (Mobile Optimized)

   • ChaCha20 stream cipher with Poly1305 MAC
   • Optimized for ARM processors (mobile devices)
   • Excellent performance without AES hardware acceleration

3. TLS_AES_128_GCM_SHA256 (High Performance)

   • AES-128 encryption with GCM mode
   • Lower computational overhead
   • Still provides strong security

TLS 1.2 Ciphers (Priority Order)

1. ECDHE-ECDSA-AES256-GCM-SHA384 / ECDHE-RSA-AES256-GCM-SHA384

   • Elliptic Curve Diffie-Hellman Ephemeral (forward secrecy)
   • AES-256-GCM (strongest symmetric encryption)
   • Preferred for high-security environments

2. ECDHE-ECDSA-CHACHA20-POLY1305 / ECDHE-RSA-CHACHA20-POLY1305

   • Forward secrecy with ECDHE
   • ChaCha20-Poly1305 (optimized for non-AES-hardware)
   • Excellent for mobile and IoT devices

3. ECDHE-ECDSA-AES128-GCM-SHA256 / ECDHE-RSA-AES128-GCM-SHA256

   • Forward secrecy with ECDHE
   • AES-128-GCM (high performance, strong security)
   • Good balance of security and performance

Testing TLS Configuration

Verify TLS 1.3 Support

# Test TLS 1.3 connection
openssl s_client -connect your-automate-fqdn:443 -tls1_3

# Expected output should show:
# - Protocol: TLSv1.3
# - Cipher: TLS_AES_256_GCM_SHA384 (or configured cipher)

Verify TLS 1.2 Support

# Test TLS 1.2 connection
openssl s_client -connect your-automate-fqdn:443 -tls1_2

# Expected output should show:
# - Protocol: TLSv1.2
# - Cipher: ECDHE-RSA-AES256-GCM-SHA384 (or configured cipher)

Verify Weak Protocols are Disabled

# These should fail with connection errors:
openssl s_client -connect your-automate-fqdn:443 -ssl3     # Should fail
openssl s_client -connect your-automate-fqdn:443 -tls1     # Should fail
openssl s_client -connect your-automate-fqdn:443 -tls1_1   # Should fail

Security Compliance

Compliance Checklist

Use this checklist to verify TLS/SSL security compliance:

• TLS 1.2 and/or TLS 1.3 enabled
• SSLv2, SSLv3, TLSv1, and TLSv1.1 explicitly disabled
• Strong ciphers configured
• Weak ciphers excluded
• Forward secrecy enabled
• Valid certificate from trusted CA
• Certificate key size >= 2048-bit RSA or 256-bit ECDSA
• Certificate expiration monitoring in place

Ensuring autocomplete remains disabled on the login screen.

A configuration maintained in Chef Automate’s nginx.conf file determines the autocomplete functionality.

add_header Cache-Control "no-cache, no-store, must-revalidate";

Please ensure you don’t update or change this configuration.