performing-ssl-tls-inspection-configuration

name	performing-ssl-tls-inspection-configuration
description	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.
domain	cybersecurity
subdomain	network-security
tags	["ssl-inspection","tls-decryption","https-inspection","certificate-management","proxy","man-in-the-middle","network-security","forward-proxy"]
version	1.0
author	mahipal
license	Apache-2.0
nist_csf	["PR.IR-01","DE.CM-01","ID.AM-03","PR.DS-02"]

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.

When to Use

• When conducting security assessments that involve performing ssl tls inspection configuration
• When following incident response procedures for related security events
• When performing scheduled security testing or auditing activities
• When validating security controls through hands-on testing

Common Misconfigurations & Verification

• CA not trusted on every store: if the inspection CA isn't in each device/browser/OS store — including app-specific stores like Firefox NSS, Java cacerts, and Python certifi — users hit cert errors or apps fail. Verify per-platform, not just Windows.
• Certificate pinning breaks silently: pinned apps (apple-update, microsoft-update, Dropbox, most mobile apps) fail under decryption, so teams add over-broad no-decrypt rules that become blind spots. Keep a tight, app-specific exemption list and review it.
• QUIC/HTTP3 bypass: browsers tunnel over UDP/443 (QUIC) and skip the TLS proxy entirely. Block UDP/443 to force HTTP/2 through inspection, then confirm no quic in traffic logs.
• TLS 1.3 0-RTT and ECH: 0-RTT early data and Encrypted Client Hello defeat SNI-based policy. Enforce min TLS 1.2, decide policy on 0-RTT, and confirm ECH handling.
• Privacy/legal exemptions: financial and health categories must bypass inspection for compliance — verify the No-Decrypt rule actually matches before any cleartext is logged.
• Fail-open vs fail-closed: know what happens when decryption resources exhaust (show system setting ssl-decrypt memory); a fail-open device silently passes uninspected traffic under load.
• Verification: openssl s_client -connect www.google.com:443 -servername www.google.com | openssl x509 -noout -issuer must show the internal inspection CA as issuer; check decryption logs for errors and confirm pinned-app exemptions haven't broadened to whole categories.