Spot and Block Network Attacks With Intrusion Detection and Prevention

An intrusion detection system watches a copy of your network traffic and raises an alert when it sees something that looks like an attack. It doesn't block anything itself. An intrusion prevention system sits in the path of the traffic and can drop it before it reaches its target. Prevention is faster but can only safely block what it's confident about; detection catches the gray areas for a person to judge. Used together, they cover both.

Firewalls inspect traffic coming in from the internet, but many attacks start inside: a laptop infected through a phishing email, or a stolen account signing in from the office. From there, an attacker moves sideways to servers and file shares, and that traffic never crosses the firewall. Watching internal traffic is how that movement gets spotted before it reaches your most important data.

Occasionally. A business application that behaves unusually can look like an attack, and an overly strict rule may block it. That's why prevention is tuned rather than switched on at the strictest setting. BCA starts with rules that catch known attacks with high confidence, watches for anything blocked by mistake and adjusts. If something your team needs is ever blocked, we can usually fix it quickly.

Someone looks at it. We check where the traffic came from, which device was involved and whether it fits normal activity for your business. If it's harmless, we tune the rule so it doesn't fire again for the same reason. If it's an attack, we contain it, usually by isolating the affected device or blocking the source, and then find out how it happened.

Most web traffic is now encrypted, which limits what any inspection tool can see inside it. IDS/IPS still sees where traffic goes, how much there is and how connections behave, which is enough to catch scanning, connections to known malicious addresses and many attack patterns. Some firewalls can also decrypt and inspect traffic, though that takes careful setup. BCA will recommend the right approach for your network.

If you take card payments, PCI DSS requires intrusion detection or prevention to watch network traffic around cardholder data. Cyber insurance applications often ask whether network traffic is monitored, and rules such as the FTC Safeguards Rule call for monitoring more generally. IDS/IPS is one of the controls that shows auditors and insurers you're watching for attacks, not just hoping the firewall holds.