Recent hacks make one thing painfully clear: no organization is hack-proof anymore. It's rarely an "if" but "when" your network defenses will get tested. And when breaches happen, the impact can be huge - from significant financial and data fallout to permanent reputational damage.
For business owners and those in charge of IT/cyber security, the pressure to lock things down is higher than ever. But in today's threat landscape, there's no such thing as a single bulletproof security solution. Savvy attackers are adept at finding weak spots and sneaking through wherever there's a gap.
The key is implementing overlapping security in layers across your system. If one defense fails or a lousy actor sips through a crack, the other layers are still standing to minimize impact.
This article outlines such a layered network security approach based on real-world best practices. Consider it your emergency preparedness guide when (not if) the hacking fires flare up.
How Do Networks Work? A Quick Security View
Before diving into security, it helps to set the level of how computer networks operate. The OSI model describes different layers of communication happening behind the scenes when you surf the web or send an email. It's kind of abstract but helpful in visualizing the hidden back-and-forth at each stop along the way. Here's a simple breakdown:
Application Layer: The top layer where you interact with apps and services like Gmail or Slack. There are lots of vulnerabilities here for attackers to target.
Presentation Layer: This layer handles encrypting and decrypting data for secure delivery, like packaging valuables before transport.
Session Layer: Manages the active "session" between apps or services you're accessing. Think real-time chat window - flaws let intruders hijack the session.
Transport Layer: Ships data packets reliably or unreliably depending on whether perfection or speed is a priority. Floods and traffic jams happen here.
Network Layer: The logical traffic controller organizes data routing and addresses between locations. It can get spoofed with fake redirects.
Data Link Layer: More nitty-gritty delivery details - addressing within the local network neighborhood. Prone to neighbor spoofing!
Physical Layer: Actual wires, wireless signals, or hardware channeling the raw ones and zeros. Tap the cables, damage the gear, and cause chaos on this layer.
Why does this matter for security? Because threats can strike at any layer as data moves through your network.
The Outer Shield: Perimeter Defenses
The outermost layer protecting your network is like the walls and gates of a castle - it controls what can enter from the outside. This first line of defense shields your system from external threats trying to sneak in, like blocking unwanted data packets trying to flow in and out.
Think of it as border security: inspecting everything crossing in either direction, only letting approved items through. These key areas help secure the perimeter:
Firewall Rules: Set up guardrails to steer incoming and outgoing traffic to the proper channels. Define what IP addresses, websites, apps, or file types are allowed or not.
VPN Access: Enable secure remote access for workers away from the office through an encrypted tunnel back to the home base. Check user IDs before opening the gate.
Intrusion Detection: Alarm systems to detect suspicious traffic patterns so threats get intercepted at the border. Automatic alerts trigger when something seems amiss.
Web App Defenses: Special firewalls that filter out dodgy traffic trying to flow in from the web to your public servers - watching for attacks like sneaky SQL injections or DDoS floods.
Updates: Can't forget security maintenance on devices facing outward - regularly installing patches and updates on firewalls, routers, and such to meet the latest defenses. Plug those holes and gaps!
The keys are intelligent inspection at checkpoints, encrypted tunnels wherever remote access is needed, alarms to detect sneaky intrusions, filters against web-based attacks, and constant upkeep. Securing the gates, walls, and guard patrols makes it much harder for unwanted data packets to get past the perimeter in either direction.
Managing The Inside: Access Controls
Once unwanted data is blocked at the perimeter, managing access within your networks' walls is the next priority. This means overseeing who or what can view, change, or interact with your systems, devices, apps, and data inside. Some key areas:
Strong Logins: Enforce strict password rules, random passcodes sent to phones/emails (multi-factor authentication), and expiring credentials before they go stale. Keep bad actors out!
Least Access Needed: Only grant users the bare minimum access to do their job and nothing more. Don't let people snoop around areas unrelated to their role - containment prevents infections from spreading.
Joiners and Leavers: Automatically open and revoke access when workers join, switch roles, or leave per HR updates. Avoid negligence around deactivating logins once someone is out the door.
Access Reviews: Double-check that current staff still need all the access their older roles granted them. Fewer hands in the cookie jar means less risk.
Essentially, the goal is to curb unnecessary internal exposure that could allow "lateral movement" - reducing gaps that let threats slip through to infiltrate deeper once perimeter defenses fail. Guard access with strict logins contains users to their discrete domains, promptly adjust permissions as roles evolve, and prune stale access no longer needed. Done right, it's much harder for vulnerabilities to metastasize internally.
Constant Vigilance: Monitoring and Detection
To catch threats that bypass the perimeter or come from inside, continuous security monitoring and anomaly detection are essential across multiple OSI layers:
Log Checkpoints: The first line of sight aggregates activity records from all systems - firewall traffic, server access logs, system events, etc. Into central locations. Analysts review the consolidated feeds to catch abnormalities.
SIEM Alarm Systems: Feeding all those logs into high-tech SIEM platforms that connect the dots in real-time using automation and algorithms to detect suspicious patterns across layers. SIEM can see the whole terrain and trigger alerts on demand.
Behavior Analysis: Machine learning aids the guards by profiling how users and systems typically act day-to-day. Comparing current activity to those set baselines makes spotting imposters easier when something seems off. Is that user accessing files they shouldn't? Did a server talk to a strange destination?
Traffic Monitoring: Additional AI threat hunting is done by continually monitoring patterns and the volume of network traffic for oddities and tuning to listen for deviations that could indicate infiltrators.
With nonstop patrols, early alarm systems, user behavior profiling, and network traffic monitoring - you have 24/7 visibility on activity across the grounds. This vigilance is crucial to catch threats that evade the outer defenses or come from within disguised as friendlies.
Final Word
The key to network security done well is to think of it as layers, starting with locking down outer access points to keep threats from sneaking in undetected. Access controls ensure that only authorized users get in and only access what they absolutely need.
Monitoring systems provide visibility by sounding alarms when they spot something suspicious. A solid frontline defense for endpoints like devices and servers keeps infections contained. It can seem overwhelming, but just take it step-by-step. Start with priorities like firewalls, VPNs, and user access controls. Make sure you've got detection systems in place watching for anomalies. Then keep building out - more endpoints protected, more logs analyzed, more scenarios tested.
It's a continuous process of observing threats, evaluating risks, and adjusting defenses. But with the right layered strategy that evolves along with the landscape - you can stay a step ahead of cyber attackers.