The Evolution of Networking: SDN to Zero Trust Firewalls

When we discuss lateral movement in a cyber attack, there’s a tendency to highlight the manner in which hackers attempt to move stealthily within a network, once they’ve made the initial inroad. And if you have been looking into firewall security or Zero Trust strategies, you know how critical it is to prevent these sleight of hand operations before they make a tremendous impact. In this blog post, we cover how firewalls prevent the spread of threats within your network.

What You Should Know About Lateral Movement

Lateral movement is like an intruder shuffling from one room to another in a building. When hackers get a foot in the door, they don’t simply hold still. They attempt to explore your network, hop between systems, search for sensitive data or gain higher-level access. This makes early detection of them incredibly important.

Why is this so dangerous?

• They are undetected as they don’t cause enormous alarms
• They fill the quiet slowly and find the juiciest targets
• They get ready for larger attacks, such as ransomware

Therefore, stopping lateral movement isn’t merely locking the front door, it’s closing their gateway behind you from the inside.

Firewall-Based Segmentation

This is the point at which firewall security comes into play. Firewalls could be considered as virtual walls of your circuit. Firewalls create smaller rooms or sections instead of one giant open office.

Firewall segmentation means:

• Segmenting your network into smaller subnets
• Rules for limiting exactly which segments can say what to whom
• Watch and prevent any unauthorized attempt to move across these segments

Benefits you get:

• Attackers who break in have their leg in one barrel
• They cannot wander freely or access all parts of the network
• You contain the blast radius of any breach

The operative phrase here is Zero Trust. In a Zero Trust model, firewalls don’t trust anything on the internal side of the network by default. Even if requests are originating from inside, every access request is validated.

Least Privilege Policies

If users and systems have too much access, firewalls alone can’t save them. That’s where least privilege policies come into play. So you want a user, device, or application to have only the permissions needed to do its job — and no more.

Adopting least privilege means:

• Regularly reviewing who requires access to what
• Setting up firewall rules that lock in these limited permissions
• Restricting users or devices access from reaching beyond their scope of resources

The method works in tandem with firewalls. The permissions are tight, so even if attackers steal credentials, they can’t move laterally.

Think about:

• Service accounts accessing only certain databases
• Employees accessing only what they need for their job role
• Only communicating with what is necessary of the network

Threat Containment

Firewalls don’t merely block unauthorized access; they’re also effective in containing threats once they’ve been detected. How? By immediately blocking connection requests that appear suspicious.

Key methods include:

• Dynamic firewall rules that respond to suspicious traffic patterns
• Isolate infected computers with network disconnection
• Blocking further communication with well known bad IPs or Devices

Containment mitigates the damage and buys your security teams time to react. These controls are needed to prevent the attacker from running free while you play catch-up.

We want to detect threats early and hold them under wraps.

Network Traffic Analysis

Firewalls are also eyes and ears to analyze network traffic. Armed with proper tools, they monitor and flag suspicious behavior such as streamlined data flow between different segments or unanticipated connections.

Some of the things firewalls call your attention to are:

• Sudden spikes in traffic in areas that typically lie dormant
• Unexplained times or routes of communication
• Spammed attempts to access high-value assets

Firewalls help in threat hunting and investigation by analyzing the traffic. They also offer vital context that can help identify lateral movement attempts before any real damage is done.

Many firewalls are integrated with logging and alerting and integrated with wider security systems that automate some responses.

Combating lateral movement requires a defence-in-depth methodology. A combination of firewalls designed using the tenets of Zero Trust, coupled with a strict least privilege ethos, segmentation of the network, containment of an attack in real-time and analysis of traffic offers an excellent line of defense against internal threats.

Just a reminder, perimeter defense is not sufficient in today’s cyber threat landscape. Zero Trust firewalls work to lock down your network like never before—closing off those invisible paths attackers love to take.

To protect your business, you need to start with lateral movement and improve firewall security as a strategy of Zero Trust to protect your business.