Agent skill

performing-ssl-tls-inspection-configuration

Configure SSL/TLS inspection on network security devices to decrypt, inspect, and re-encrypt HTTPS traffic for threat detection while managing certificates, exemptions, and privacy compliance.

View SKILL.md on GitHub Repository
Stars 0
Forks 0

Install this agent skill to your Project

npx add-skill https://github.com/autohandai/community-skills/tree/main/performing-ssl-tls-inspection-configuration

SKILL.md

Performing SSL/TLS Inspection Configuration

Overview

SSL/TLS inspection (also called SSL decryption, HTTPS inspection, or TLS break-and-inspect) intercepts encrypted traffic between clients and servers to inspect the cleartext content for malware, data exfiltration, policy violations, and command-and-control communications. The inspection device acts as a trusted man-in-the-middle, terminating the TLS session from the client, inspecting the plaintext content, and establishing a new TLS session to the destination server. With over 95% of web traffic now encrypted, organizations without TLS inspection have a massive blind spot. This skill covers configuring TLS inspection on next-generation firewalls, deploying trusted CA certificates, managing exemptions for certificate-pinned applications, and ensuring compliance with privacy regulations.

Prerequisites

  • Next-generation firewall or secure web gateway with TLS inspection capability
  • Internal Certificate Authority (CA) for signing inspection certificates
  • Endpoint certificate management (GPO, MDM, or manual deployment)
  • Privacy and legal review for TLS inspection scope
  • Understanding of PKI, X.509 certificates, and TLS handshake

Core Concepts

SSL/TLS Inspection Modes

Mode Direction Description
SSL Forward Proxy Outbound Intercepts client-to-internet HTTPS connections
SSL Inbound Inspection Inbound Decrypts traffic destined for internal servers
SSH Proxy Both Inspects SSH tunneled traffic

Forward Proxy Process

Client                  Firewall/Proxy              Web Server
  │                         │                          │
  │──TLS ClientHello──────→│                          │
  │                         │──TLS ClientHello───────→│
  │                         │←─TLS ServerHello────────│
  │                         │  (real server cert)      │
  │                         │                          │
  │                         │  [Validates server cert]  │
  │                         │  [Generates proxy cert   │
  │                         │   signed by internal CA]  │
  │                         │                          │
  │←─TLS ServerHello───────│                          │
  │  (proxy-signed cert)    │                          │
  │                         │                          │
  │──Encrypted data────────→│  [Decrypt, Inspect]      │
  │                         │──Encrypted data────────→│
  │←─Encrypted data─────────│  [Decrypt, Inspect]      │
  │                         │←─Encrypted data─────────│

Certificate Trust Chain

Enterprise Root CA
  └── Subordinate CA (SSL Inspection)
        └── Dynamically Generated Server Certificates
             (CN matches requested server)

Implementation Steps

Step 1: Generate Internal CA for SSL Inspection

bash
# Create private key for SSL Inspection CA
openssl genrsa -aes256 -out ssl-inspect-ca.key 4096

# Create CA certificate (5 year validity)
openssl req -new -x509 -key ssl-inspect-ca.key \
  -sha256 -days 1825 \
  -out ssl-inspect-ca.crt \
  -subj "/C=US/ST=California/O=Corp Inc/OU=Network Security/CN=Corp SSL Inspection CA" \
  -extensions v3_ca \
  -config <(cat <<EOF
[req]
distinguished_name = req_dn
x509_extensions = v3_ca

[req_dn]

[v3_ca]
basicConstraints = critical,CA:TRUE,pathlen:0
keyUsage = critical,digitalSignature,keyCertSign,cRLSign
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always
EOF
)

# Verify certificate
openssl x509 -in ssl-inspect-ca.crt -text -noout

Step 2: Deploy CA Certificate to Endpoints

Windows (Group Policy):

powershell
# Import CA cert to trusted root store via GPO
# Computer Configuration > Policies > Windows Settings >
# Security Settings > Public Key Policies > Trusted Root CAs

# Or deploy via PowerShell
Import-Certificate -FilePath "\\server\share\ssl-inspect-ca.crt" `
  -CertStoreLocation "Cert:\LocalMachine\Root"

# Verify deployment
Get-ChildItem Cert:\LocalMachine\Root | Where-Object {
    $_.Subject -like "*SSL Inspection CA*"
}

macOS (MDM profile or manual):

bash
# Install via command line
sudo security add-trusted-cert -d -r trustRoot \
  -k /Library/Keychains/System.keychain ssl-inspect-ca.crt

Linux:

bash
# Ubuntu/Debian
sudo cp ssl-inspect-ca.crt /usr/local/share/ca-certificates/
sudo update-ca-certificates

# RHEL/CentOS
sudo cp ssl-inspect-ca.crt /etc/pki/ca-trust/source/anchors/
sudo update-ca-trust

Step 3: Configure Palo Alto SSL Forward Proxy

# Import CA certificate to firewall
# Device > Certificate Management > Certificates > Import

# Set as Forward Trust CA
set shared certificate SSL-Inspect-CA forward-trust-certificate yes

# Create Decryption Profile
set profiles decryption Corporate-Decrypt ssl-forward-proxy block-expired-certificate yes
set profiles decryption Corporate-Decrypt ssl-forward-proxy block-untrusted-issuer yes
set profiles decryption Corporate-Decrypt ssl-forward-proxy block-unknown-cert yes
set profiles decryption Corporate-Decrypt ssl-forward-proxy restrict-cert-exts yes
set profiles decryption Corporate-Decrypt ssl-forward-proxy strip-alpn no

# Minimum TLS version
set profiles decryption Corporate-Decrypt ssl-protocol-settings min-version tls1-2
set profiles decryption Corporate-Decrypt ssl-protocol-settings max-version max

# Decryption policy - decrypt outbound HTTPS
set rulebase decryption rules Decrypt-Outbound from Trust to Untrust
set rulebase decryption rules Decrypt-Outbound source any
set rulebase decryption rules Decrypt-Outbound destination any
set rulebase decryption rules Decrypt-Outbound service any
set rulebase decryption rules Decrypt-Outbound action decrypt
set rulebase decryption rules Decrypt-Outbound type ssl-forward-proxy
set rulebase decryption rules Decrypt-Outbound profile Corporate-Decrypt

Step 4: Configure Exemptions

Certain applications and categories must be excluded from TLS inspection:

# Exempt certificate-pinned applications
set rulebase decryption rules No-Decrypt-Pinned from Trust to Untrust
set rulebase decryption rules No-Decrypt-Pinned application [ apple-update microsoft-update dropbox-base ]
set rulebase decryption rules No-Decrypt-Pinned action no-decrypt

# Exempt privacy-sensitive categories
set rulebase decryption rules No-Decrypt-Privacy from Trust to Untrust
set rulebase decryption rules No-Decrypt-Privacy category [ health-and-medicine financial-services ]
set rulebase decryption rules No-Decrypt-Privacy action no-decrypt

# Exempt specific high-trust domains
set rulebase decryption rules No-Decrypt-Trusted from Trust to Untrust
set rulebase decryption rules No-Decrypt-Trusted destination [ bank-of-america.com chase.com healthcare.gov ]
set rulebase decryption rules No-Decrypt-Trusted action no-decrypt

Step 5: Configure Inbound Inspection for Internal Servers

# Import server certificate and private key
# Device > Certificate Management > Certificates > Import

# Inbound inspection policy
set rulebase decryption rules Inspect-WebServers from Untrust to DMZ
set rulebase decryption rules Inspect-WebServers destination [ 10.0.20.10 10.0.20.11 ]
set rulebase decryption rules Inspect-WebServers service service-https
set rulebase decryption rules Inspect-WebServers action decrypt
set rulebase decryption rules Inspect-WebServers type ssl-inbound-inspection
set rulebase decryption rules Inspect-WebServers profile Corporate-Decrypt

Step 6: Validate SSL Inspection

bash
# Test from client - verify certificate issuer is internal CA
openssl s_client -connect www.google.com:443 -servername www.google.com 2>/dev/null | \
  openssl x509 -noout -issuer -subject

# Expected output (with inspection active):
# issuer= /C=US/O=Corp Inc/OU=Network Security/CN=Corp SSL Inspection CA
# subject= /CN=www.google.com

# Verify no certificate errors in browser
# Check firewall decryption logs for errors

# Test with curl
curl -v https://www.example.com 2>&1 | grep "issuer"

# Check decryption statistics on firewall
show system setting ssl-decrypt memory
show system setting ssl-decrypt certificate-cache
show counter global filter category ssl

Performance Considerations

Factor Impact Mitigation
CPU overhead 50-80% increase per session Hardware SSL acceleration, dedicated decrypt appliance
Throughput reduction 40-60% typical Size decryption hardware for peak encrypted traffic
Latency increase 1-5ms additional Place inspection close to users
TLS 1.3 0-RTT Cannot inspect 0-RTT data Block 0-RTT or accept risk
Certificate pinning Inspection fails Add to exemption list
QUIC/HTTP3 Bypasses traditional proxy Block QUIC, force HTTP/2

Compliance and Privacy

  • Employee Notice - Notify users that network traffic is subject to inspection
  • Privacy Exemptions - Exclude healthcare, financial, and legally privileged traffic
  • Data Handling - Inspected cleartext must not be logged or stored unnecessarily
  • GDPR Compliance - Document lawful basis for processing encrypted personal data
  • Certificate Pinning - Maintain exemption list for applications using HPKP or built-in pins

Best Practices

  • Start with Logging - Deploy in detect-only mode first to identify certificate-pinned applications
  • Maintain Exemption List - Keep a curated list of applications requiring decryption bypass
  • Block QUIC - Block UDP/443 to force HTTP/2 through TLS inspection
  • Monitor Certificate Errors - Track decryption errors in firewall logs
  • TLS 1.2 Minimum - Enforce TLS 1.2 as minimum version; block SSLv3 and TLS 1.0/1.1
  • Key Protection - Store inspection CA private key in HSM for production environments
  • Regular CA Rotation - Plan for CA certificate rotation before expiration

References

Recommended Agent Skills

Expand your agent's capabilities with these related and highly-rated skills.

autohandai/community-skills

mapping-mitre-attack-techniques

Maps observed adversary behaviors, security alerts, and detection rules to MITRE ATT&CK techniques and sub-techniques to quantify detection coverage and guide control prioritization. Use when building an ATT&CK-based coverage heatmap, tagging SIEM alerts with technique IDs, aligning security controls to adversary playbooks, or reporting threat exposure to executives. Activates for requests involving ATT&CK Navigator, Sigma rules, MITRE D3FEND, or coverage gap analysis.

0 0
Explore
autohandai/community-skills

hunting-for-spearphishing-indicators

Hunt for spearphishing campaign indicators across email logs, endpoint telemetry, and network data to detect targeted email attacks.

0 0
Explore
autohandai/community-skills

analyzing-malicious-url-with-urlscan

URLScan.io is a free service for scanning and analyzing suspicious URLs. It captures screenshots, DOM content, HTTP transactions, JavaScript behavior, and network connections of web pages in an isolat

0 0
Explore
autohandai/community-skills

implementing-zero-standing-privilege-with-cyberark

Deploy CyberArk Secure Cloud Access to eliminate standing privileges in hybrid and multi-cloud environments using just-in-time access with time, entitlement, and approval controls.

0 0
Explore
autohandai/community-skills

implementing-pam-for-database-access

Deploy privileged access management for database systems including Oracle, SQL Server, PostgreSQL, and MySQL. Covers session proxy configuration, credential vaulting, query auditing, dynamic credentia

0 0
Explore
autohandai/community-skills

detecting-t1003-credential-dumping-with-edr

Detect OS credential dumping techniques targeting LSASS memory, SAM database, NTDS.dit, and cached credentials using EDR telemetry, Sysmon process access monitoring, and Windows security event correlation.

0 0
Explore

Didn't find tool you were looking for?

Be as detailed as possible for better results