How to Reduce an Attack Surface

Every device, application, and system connected to the internet represents a potential entry point for cyber attackers. Collectively, these points of exposure form what is known as your organisation’s attack surface.

From hardware and software to mobile devices and cloud services, each connection is an opportunity for threat actors to exploit weaknesses, for financial gain or to cause disruption.

Research shows that over 80% of organisations report that changes to their external attack surface contribute to security incidents, yet many lack mature processes to manage these exposures.

In other words, as businesses introduce new systems, services, or devices, they can unintentionally create vulnerabilities without fully understanding or controlling the associated risks.

Minimising your attack surface is a central goal of any effective cybersecurity strategy. The smaller and more controlled your exposure, the easier it is to protect critical systems and sensitive data.

However, this is not a one-off task. As technology evolves and attackers develop new methods, your attack surface must be continuously assessed and monitored to ensure your defences remain effective.

We’ll cover how to reduce an attack surface below, so you can gain clarity on where your organisation, including its extended network of suppliers, may be vulnerable.

What Is an Attack Surface In Cyber Security?

An attack surface is the total of all points where a hacker could potentially gain access to your systems and data. Every connection, device, or application that interacts with your network adds to this surface, creating opportunities for exploitation.

Each of these points of exposure is known as an attack vector, a specific route a hacker could use to breach your systems.

Attack vectors can include expired certificates, weak or stolen credentials, vulnerable software, and human behaviour, such as falling for phishing attacks.

Attack surfaces can be grouped into three main categories:

Digital Attack Surface: All internet-facing hardware, software, and applications. Hackers can scan these remotely to identify weaknesses.

Human Attack Surface: Risks arising from employee behaviour, whether intentional or accidental, that could expose sensitive information.

Physical Attack Surface: On-site assets, including laptops, servers, network hardware, and other equipment that could be accessed or tampered with.

Identifying your attack surface and its associated vectors is a crucial step in understanding risks and protecting critical systems.

Every connection, device, or application that interacts with your network adds to your attack surface, creating opportunities for exploitation.

How to Reduce Your Attack Surface

With a clear picture of your attack surface, you can now take practical steps to reduce vulnerabilities, limit potential entry points, and strengthen your organisation’s overall security.

Analyse Your Attack Surface

The first step in reducing your organisation’s attack surface is understanding all the points where systems, data, and users could be exposed.

This process, called attack surface analysis, maps your network, applications, devices, and user access to identify vulnerabilities before attackers can exploit them.

Key steps include:

Inventory assets: Document all systems, applications, devices, and data paths that could be accessed externally.
Review user access: Focus on roles and permissions to see where potential risks lie.
Assess vulnerabilities: Scan for weaknesses such as outdated software, exposed code, or weak credentials.
Evaluate risk: Prioritise vulnerabilities based on potential impact and likelihood.
Plan mitigation: Reduce exposure by patching weaknesses, restricting unnecessary access, and strengthening security practices.

Regular attack surface assessments help your organisation keep pace with evolving threats and stay ahead of potential attackers.

The first step in reducing your organisation’s attack surface is understanding all the points where systems, data, and users could be exposed.

Use Network Segmentation to Limit Risk

Network segmentation is a powerful strategy for reducing your attack surface by containing potential security incidents.

By dividing your network into smaller, isolated segments, you can restrict how far an attacker can move if they gain access to a part of your systems.

Key steps to effective segmentation include:

Divide the network into zones: Group systems and devices based on their function, applying tailored security policies and access controls to each segment.
Control communication between segments: Use firewalls and access rules to ensure only authorised traffic can pass between zones.
Monitor and log activity: Deploy monitoring tools to detect suspicious behaviour and track potential intrusions within the network.
Isolate critical systems: Place high-value assets, such as servers and databases, in dedicated segments to make them harder for attackers to reach.

These techniques can limit the impact of a breach and improve overall security management.

Implement a Zero Trust Security Model

A zero-trust security approach assumes that no user or device, whether inside or outside your network, can be automatically trusted. Every access request is verified, ensuring that only authorised users and devices can reach sensitive systems or data.

Key elements of a zero-trust security model include:

Multi-factor authentication (MFA): Requires multiple forms of verification, such as passwords combined with security tokens, to make it harder to compromise accounts.
Granular access control: Apply fine‑grained permissions based on roles, attributes, or context to ensure users can only access the data and systems essential for their work.
Continuous monitoring: Track network traffic and device activity in real time, potentially using AI-driven tools, to quickly detect and respond to unusual behaviour.
Least Privilege Principle: Ensure users and devices are granted only the minimum access necessary to perform their tasks, reducing the risk of misuse or lateral movement within the network.

A zero-trust security approach assumes that no user or device, whether inside or outside your network, can be automatically trusted.

Implement Strong Encryption Policies

Encryption is one of the most effective ways to protect sensitive data and reduce your organisation’s attack surface.

Even if information is intercepted, leaked, or moved outside your systems, strong encryption ensures it remains secure and unreadable to unauthorised parties.

A solid encryption strategy should cover:

Encryption methods: Use modern, secure cipher suites and replace legacy systems that cannot support strong encryption.
Data classification: Identify which information is sensitive or critical, including personal, financial, or proprietary data.
Data location: Map where classified or sensitive data is stored across servers, databases, and cloud environments.
Compliance alignment: Ensure encryption policies meet industry or regulatory requirements, such as healthcare standards or government guidelines.

Implementing these measures can help organisations safeguard sensitive information, reduce the risk of data exposure, and strengthen their overall cyber security posture.

How Can We Help

If you’re wondering how to reduce an attack surface, it starts with understanding your systems, limiting exposure, and continuously monitoring for risks.

However, internal security measures alone aren’t enough. Your external systems, cloud services, and supply chain can introduce hidden vulnerabilities that traditional security tools can miss.

That’s where our External Attack Surface Management (EASM) service comes in. We help organisations discover vulnerabilities, monitor third-party risks, and prioritise the more critical threats for effective remediation.