What is not online cannot be hacked. In today’s digital landscape, that simple truth is more relevant than ever. As organizations expand their online presence through cloud services and third-party integrations, their attack surface grows with it. Every exposed domain, subdomain, open port, or misconfigured service becomes a potential entry point for attackers.

That’s why organizations today must take proactive steps to reduce the attack surface. By minimizing your exposed footprint, you not only reduce the number of potential vulnerabilities but also make it significantly harder for bad actors to find a way in. A leaner, more controlled digital presence improves your organization’s resilience and makes opportunistic attacks less likely.

In this article, we’ll explore what the attack surface is and how to minimize it effectively.

What is an attack surface?

An attack surface refers to all the points in your IT infrastructure where an unauthorized user (typically a cyber attacker) could try to enter or extract data from an environment. This includes all hardware and software, as well as anything that is internet-facing or externally accessible. For example:

• Public websites and web applications
• IP addresses and open ports
• Software applications
• Cloud infrastructure and services
• Third-party integrations
• Physical access points to devices/networks
• Unused or forgotten subdomains and assets

External attack surfaces — which specifically refers to all internet-facing assets — are particularly vulnerable these days thanks to their rapid proliferation. As companies try to keep up with trends like cloud migration, AI, and remote work, their external attack surface grows larger and larger. And as it grows, it becomes more and more difficult for IT teams to keep track of what they actually have exposed online.

The more assets you expose online, the greater your risk; each entry point can be exploited if left unpatched or unmonitored. In fact, research revealed that 76% of organizations reported an attack due to an exposed asset in 2024.

That’s why reducing your attack surface is such a vital and necessary part of modern cybersecurity strategies. Keeping your attack surface manageable and visible is key to being able to defend it against external threats.

What is attack surface reduction?

Attack surface reduction is the process of minimizing the number of potential entry points attackers can exploit within an organization’s digital environment. This involves identifying and eliminating unnecessary or outdated internet-facing assets, like exposed servers, subdomains, open ports, and misconfigured services.

Organizations that actively reduce attack surface exposure are better equipped to prevent data breaches and cyber incidents.

5 key steps to reduce the attack surface

Minimizing your attack surface isn’t a one-time project; it’s a continuous, evolving process. Here are four essential steps your organization can follow to reduce digital exposure and stay ahead of attackers:

1. Map all internet-facing assets and check them regularly

Reconnaissance is the first step in a cybercriminal’s attack plan. They begin by gathering as much information as possible about the target organization.

To stay ahead of this, every organization needs a clear and complete understanding of its digital footprint. This might include:

• Active and inactive subdomains
• IP addresses and open ports
• Web servers and applications
• Cloud resources
• Exposed development or staging environments
• Forgotten assets from past marketing campaigns or brand acquisitions

Simply put: you can’t protect what you don’t know you have.

2. Prioritize and classify risk

Not all assets carry the same level of risk. After discovering what you have exposed, the next step is to classify and prioritize it based on the potential threat. This means evaluating assets based on things like:

• Business criticality
• Data sensitivity
• Known vulnerabilities
• Configuration issues
• Exposure level (public/private)

Even the largest teams usually have limited resources to deal with threats, so it’s really important to be able to identify which are the most critical and focus first on high-risk, high-impact assets.

3. Eliminate or remediate unnecessary assets

Digitalization is everywhere, and it’s accelerating. That’s why it’s essential to track and monitor your organization’s digital transformation from the very beginning. This includes not only your internal assets but also the third-party providers supporting your business operations.

Once you know what you have exposed and how risky it is, begin reducing your attack surface by removing unused, unknown, or unnecessary assets. If something is no longer needed, remove it from the network — because what isn’t online, can’t be hacked.

Eliminating unnecessary assets may include:

• Decommissioning unused systems (e.g. old test environments or legacy applications)
• Closing unnecessary open ports
• Retiring domains or subdomains that are no longer tied to active business use
• Patching or reconfiguring misconfigured assets

4. Adopt a zero-trust mindset

A critical and often overlooked way to reduce the attack surface is by implementing a zero-trust security model. Unlike traditional perimeter-based defenses that assume everything inside the network is trustworthy, zero trust assumes breach and requires verification for every access request, regardless of where it originates.

Thanks to remote work, rapid cloud adoption and third-party integrations, there’s no such thing as a clearly defined network perimeter. Users, applications, and data live everywhere, and attackers will absolutely take advantage of that decentralization.

By removing implicit trust and requiring authorization for every access attempt, you can dramatically reduce the chances of lateral movement after an initial breach.

5. Continuously monitor for vulnerabilities

Visibility over your assets shouldn’t rely on one-off scans or best-effort attempts — it needs to be continuous and up to date. That means knowing which hosts are active, how they’re configured, which web applications are exposed, identifying security issues, and detecting any sensitive data unintentionally shared in the cloud.

Using dynamic, real-time vulnerability assessments instead of relying only on static, periodic scans allows your team to respond to threats as they emerge and keep pace with your constantly evolving environment.

Outpost24’s External Attack Surface Management (EASM) solution continuously scans your entire attack surface for known and unknown IT assets, identifying blind spots so you can take control of them and ultimately improve security. Interested in how this could help reduce your organization’s attack surface? Book a free demo today.

How to identify attack surface reduction candidates

Identifying and inventorying candidates for attack surface reduction can be a challenge, but the Outpost24 EASM solution can help. Our platform maps your entire attack surface, monitoring all your internet-facing assets and identifying candidates for removal.

Websites & domains

From a websites and domains perspective, our EASM platform helps identify assets that may no longer serve a business purpose. For example, why leave an old marketing site exposed — especially if it’s running unpatched third-party code from two years ago?

Similarly, domains from previously acquired brands might still be online, untracked, unsecured, and outdated. These forgotten assets can create easy entry points for attackers, and your company’s reputation could be at stake if exploited.

The Outpost24 EASM platform delivers the situational awareness you need by continuously monitoring all your hosts, domains, websites, and more, so you can take action before issues become incidents.

Third party providers

The Outpost24 EASM solution allows you to identify unknown outliers across your third-party provider landscape. It identifies small clusters or isolated assets that may be overlooked but still pose risk. By revealing these low-volume, potentially unnecessary components, you can take steps to verify, consolidate, or remove them — making your attack surface leaner while also reducing unnecessary costs, such as recurring hosting or service fees.

Shadow IT

Because our EASM platform maps your external attack surface from an outside-in perspective, it provides visibility into assets that are often overlooked, commonly referred to as shadow IT. These are systems, applications, or services that exist outside the awareness of your IT or security teams, often without formal approval or proper oversight.

Shadow IT not only consumes valuable resources and budget without delivering traceable business value, but it also introduces serious security risks. Untracked assets are often unpatched, misconfigured, or completely unmanaged, making them prime targets for attackers.

By continuously scanning your internet-facing perimeter, our EASM identifies these blind spots so you can take control of them and ultimately improve security.

Simplify attack surface reduction with Outpost24 EASM

Our Outpost24 External Attack Surface Management platform is purpose-built to help organizations reduce and manage their external attack surface. Through continuous discovery and prioritized risk insights, we give security teams the visibility and control they need to act fast and stay ahead of threats.

Ready to reduce your attack surface and take control of your organization’s external exposure? Schedule your personalized demo with one of our experts today.