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What is External Attack Surface Management (EASM)?

External Attack Surface Management (EASM) refers to the process of identifying, analyzing, and managing an organization's external attack surface.

6 minutes read

External Attack Surface Management (EASM) refers to the process of identifying, analyzing, and managing an organization's external attack surface. The external attack surface specifically focuses on the points that are accessible from outside the organization, such as through the internet.

While proactively identifying and mitigating risks can help to ensure compliance, the primary focus of EASM is safeguarding against potential breaches. In this article, we’ll take an in-depth look at EASM, including important criteria for choosing an effective EASM solution. Let’s get started.

Understanding external attack surfaces

An external attack surface (EAS) refers to digital elements that are exposed for attackers to see, access, or manipulate. From web applications, servers, and APIs to network infrastructure, it’s essential to manage every potential way into your system to minimize the likelihood of a breach. EAS management encompasses processes, services, and tools you can use to manage the security of exposed entry points.

There is a common misconception that EASM is exclusively for large companies, but that couldn’t be further from the truth. Imagine a small company whose web application was built on a cloud computing framework, with their data hosted on a remote server. Their external attack surface expands to include common vulnerabilities of a web application, such as a SQL injection (SQLi) or a cross-site scripting (XSS) attack. Human error is also part of the equation: A misconfiguration of the cloud environment could potentially lead to unauthorized access to sensitive information. 

That’s where an EASM solution comes in. An EASM tool would help this organization by:

  • executing automated scans to uncover vulnerabilities

  • providing a clear prioritization of threats

  • offering continuous monitoring of both the web application and the cloud environment

According to Verizon's Data Breach Investigations Report (DBIR), 83% of security breaches that happened in 2023 were performed by external attackers. In 95% of cases, these external attackers had financial motives, and 24% of all breaches had a ransomware attack component. Simply put, attackers are looking for vulnerable companies to target, so management of your external attack surface is a top priority.

The benefits of external attack surface management

  • Visibility: With its mapping capability and risk prioritization, EASM provides deep visibility into potential threats.

  • Reduced risks: Security risks are greatly reduced because of EASM’s prompt detection.

  • Compliance: EASM helps the compliance team ensure the alignment of their company's resources with standards and regulations, thanks to the automated discovery feature.

  • Swift incident response: EASM supports a swift incident response with its threat intelligence integration.

  • Efficient resource allocation: When prioritizing risks, EASM ensures efficient resource allocation by focusing on criticality and streamlining responses.

EASM’s challenges

One of the main challenges to effective EASM is the dynamic nature of the systems, software, and devices that organizations rely on. Each of these environments have their own setup, parameters, connections, and integrations—adding another layer of difficulty to their management. 

But there’s more complexity to add to the mix. Virtualization, diverse infrastructures, and the use of cloud services all complicate the process of mapping all components accurately. It’s a common problem. In fact, research shows that on average, companies don’t know about 64% of their programs and devices that are connected to the internet. This shadow IT presents a severe security risk and a slew of potential compliance violations. 

Moreover, new technologies are constantly emerging, which can elude existing security measures and introduce new vulnerabilities into your system. In order to close vulnerability gaps in this evolving landscape, an ideal EASM solution must be adaptable enough to continuously update your security protocols. Now let’s turn our attention to other features that robust EASM tools should offer.

Key features for an EASM solution

  • Automated discovery and mapping: Because it’s common to find unauthorized resources being used by employees to assist them on their daily tasks, EASM tools provide automated discovery. With this feature, IT or security teams can detect every internet-facing asset present within an organization’s landscape. After mapping, an EASM solution can perform a vulnerability assessment on each of them. 

  • Continuous monitoring: EASM tools offer monitoring and an integrated threat intelligence model that enables you to detect, analyze, and respond to threats as soon as they emerge.

  • Prioritization of risks: Every vulnerability has a different criticality. EASM shines when it comes to ranking threats according to their risk. This way, organizations can analyze and patch the vulnerabilities that imply a higher risk.

Comparing EASM with other solutions and strategies

EASM vs. internal attack management

Unfortunately, threats don’t just come from external sources, making internal attack management a necessity. Monitoring and securing internal assets, systems, and information from threats originating from within an organization’s network infrastructure can be complex. Fortunately, there are some well-known best practices and tools that can fortify internal security:

  • Access controls and user authorizations: By implementing robust access-control policies, organizations can ensure that users have access only to the resources necessary to perform their job. This reduces the risk of unauthorized access and helps prevent threats within the organization’s landscape.

  • Intrusion prevention systems (IPS): IPS solutions monitor network traffic for known attack patterns and automatically block them. With the help of an IPS tool, organizations can prevent unauthorized access attempts, malware infections, and other malicious activities within their network infrastructure.

  • Network segmentation: By dividing the network into isolated segments with their own security policies, organizations can contain the impact of security incidents. Segmentation helps prevent lateral movement—for example, malware trying to quickly spread or an attacker who managed to access one of the network’s segments in order to gain access to the entire system.

  • Security information and event management (SIEM): SIEM tools collect and analyze security events from various sources such as firewalls, servers, and endpoints. They usually provide near real-time visibility of security incidents, allowing security teams to respond to threats promptly.

The main difference between EASM and internal attack management comes down to scope. While EASM focuses on external-facing assets, internal attack management protects internal systems, data, and infrastructure from malware infections, data exfiltration, unauthorized access, and service disruptions, among others.

Or to put it simply, internal attack management is as essential as EASM, but it focuses on elements within an organization. The goal of both approaches is to mitigate threats and vulnerabilities but in different fields of an organization’s landscape. Best practice is to have robust internal attack management complementing your EASM strategy.


EASM focuses on the internet-facing assets, while cyber asset attack surface management (CAASM) takes a broader approach by considering both internal and external assets and their vulnerabilities. Some examples of the assets covered by CAASM are databases, servers, and applications.

When it comes to data sources, CAASM usually requires an integration via API with internal tools (or even with EASM) to passively collect data that can then be queried for deeper analysis. This process requires effort not only from security and IT teams but also from developers, resulting in a costly implementation. On the other hand, EASM directly discovers assets by using the same techniques for every company, meaning no developers have to deal with a complex integration.

CAASM’s implementation can be expensive, but it does provide some interesting benefits too. The most important advantage is a real-time updated view of your asset inventory. CAASM frees up teams who would otherwise be responsible for manual asset inventory, increasing their productivity and presenting a clear attack surface.

Once more, the main challenge is the aforementioned shadow IT. While EASM performs reconnaissance activities to look for all the external-facing infrastructure, CAASM technologies often map assets by being integrated with them. Consider this example: An employee deploys a simple application and exposes it externally for testing reasons. EASM is more likely to find it by scanning the network, while CAASM won’t because it is not integrated with the application.

Finally, one more distinction that also deserves mention is about the vulnerability management process. EASM often automates this process by discovering and prioritizing vulnerabilities by criticality, while CAASM relies more on manual processes.

To sum up, although EASM is much easier to set up, CAASM brings a more holistic response by covering internal and external assets.


External attack surface management is not just another cybersecurity tool. Instead, it’s an essential strategy for properly managing the external attack surface and safeguarding digital assets. In this article, we’ve explored EASM’s challenges and how to overcome them in order to successfully leverage external attack surface management’s key features. When applied correctly, EASM tools empower you to proactively address vulnerabilities, prioritize risks based on their criticality, and keep a vigilant eye on your external attack surface. 

We recommend a comprehensive approach such as the one provided by EASM, combined with the holistic coverage of CAASM and robust internal management to keep you one step ahead in the constantly changing threat landscape. 

Luckily, you don’t have to tackle security alone. If you’re looking to protect everything you build and run in the cloud, look no further than Wiz. Our industry-leading, all-in-one platform is trusted by 40% of Fortune 100 companies to bolster security. Curious about what Wiz can do for you? Book a demo today.

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