So we're all sitting here staring at the QRadar dashboard, convinced we've got total visibility, while half the network traffic is sliding by under the TLS blanket. The official line is, of course, "use the QRadar Flow Collector with a decryption device or mirror from your edge." Great. In theory.
But let's get practical. If you're actually trying to do this for threat detection and not just compliance checkboxing, the architecture gets... interesting.
Are you guys doing passive decryption at the firewall and mirroring cleartext to a Flow Collector? Or are you deploying the Packet Capture appliances in strategic choke points? I've seen setups where the performance hit from decryption on busy web applications makes the network team revolt, so the "strategic" inspection ends up being just the guest Wi-Fi and the printer VLAN. Not exactly a treasure trove of threats.
And then there's the certificate management nightmare. How are you handling the internal CA, device trust, and exemptions for health checks, payment processors, etc.? The moment you start making exemptions is the moment your coverage plot develops more holes than swiss cheese.
I'm curious about real-world data volumes too. Once you start feeding decrypted metadata into QRadar, does your event/flow rate double? More? Are you actually building useful rules off the decrypted app-layer data, or is this just an expensive way to watch your HTTPS traffic go up and down?
just sayin'
Data over dogma.
You've identified the core tension perfectly: the theoretical model of full decryption collides with practical constraints on performance and manageability.
Our approach evolved from a similar "decrypt everything" stance. We found that attempting passive decryption at the firewall for all traffic introduced unacceptable latency jitter, particularly for internal microservice communication. We shifted to a targeted model based on explicit network trust zones. The "choke point" strategy only works if you define the choke points by risk, not just by topology.
The certificate management is indeed the hidden cost. We maintain a separate, short-lived internal CA purely for inspection, which automates device trust provisioning but creates its own operational overhead. Exemptions are inevitable, but you can contain the damage by defining them at the service or domain level via a policy engine, rather than making ad-hoc IP-based rules. This still leaves blind spots, but they become a conscious architectural decision rather than a configuration accident.
brianh