External attack surface management (EASM) refers to the process of identifying risks originating from Internet-facing assets and systems. Apart from processes, EASM also encompasses the necessary technologies to discover external-facing assets and manage their vulnerabilities, if any.

EASM includes managing servers, credentials, public cloud misconfigurations, and third-party partner software code vulnerabilities that threat actors could exploit to get to their intended targets. At its core, EASM takes an outside-in view into an organization to identify and mitigate threats that exist beyond its network perimeter.

Other interesting terms…

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Before we talk more about EASM, let’s define what an attack surface is.

What Is an Attack Surface?

An attack surface refers to all the possible points where unauthorized users can try to input or extract data from a system or network. That makes keeping an organization’s attack surface as small as possible a basic cybersecurity measure.

In a home, we can say that all of the doors and windows are potential attack entry points (for thieves and other unwelcome visitors). So its owner must keep all of the entryways locked at night or when no one is at home.

EASM is part and parcel of vulnerability and threat management. It encompasses two subprocesses discussed in greater detail in the following section.

What Are the Components of External Attack Surface Management?

EASM primarily involves asset discovery and vulnerability analysis.

Asset Discovery

Asset discovery is all about knowing about every IT asset your organization owns. That is because you can only secure systems and solutions you are aware of. You should know that the most effective way for hackers to bypass security is to access an insufficiently secured or totally unsecured device, normally one that its owner forgot about or decommissioned without deleting from the network.

That said, EASM involves performing an inventory of all your exposed or vulnerable IT assets. It should also look at all of the third parties you have allowed network access to.

Vulnerability Analysis

Knowing assets exist, however, isn’t enough. You should also determine if they have vulnerabilities that threat actors can exploit, putting your organization at great risk.

Any bug should be brought to light as soon as possible. That way, no one can take advantage of it to break into your network.

Vulnerability analysis encompasses prioritization as well. If several bugs are found in systems or solutions, it’s not possible to address them all at once. In such a case, therefore, fixing the worst vulnerability (the one that poses the greatest risk) should be prioritized over others.

What Are the Main Challenges in External Attack Surface Management?

Cloud computing and IT democratization are probably the main factors that made EASM necessary. But as much as they allowed organizations greater flexibility and lower operational costs by empowering users to access and utilize the technologies they wish to, they also caused users to have major blind spots and limited visibility. Companies are no longer as privy to their so-called “shadow IT” and asset exposure on the Internet.

Shadow IT refers to using IT systems, devices, software, applications, and services without explicit IT department approval. Listed below are some challenges related to EASM.

Distributed IT Ecosystems

Today’s organizations no longer have well-defined network perimeters or boundaries. Most have assets in various places due to having regional offices and subsidiaries, working with third-party vendors, and giving access to business partners. As companies expand their network beyond what they have full control and visibility over (inside their firewalls), the more exposed they get.

Siloed Teams

Almost all organizations are divided into several teams. And each team can manage their own set of Internet-connected assets. Sometimes, these assets remain unknown to the company’s IT team. These assets were, in fact, put up so their owners can deliver results faster even if they have to bypass established security protocols and policies. As such, the Internet-facing properties that remain secret from security personnel could put the organization at great risk.

Constantly Evolving External Attack Surfaces

Every addition to your network (a new partner, subsidiary, or team) expands your network. At times, network expansion leads to more shadow IT. Keeping track of all applications and services becomes more complicated and even impossible. Even a wrong click can translate to an additional risk.

The bottom line is, hackers will always find effective ways to bypass organizations’ network perimeters. And often, attacking connected third parties is the way to do that. But due to the sheer number of exposed assets, securing them all could take a lot of resources and may not even be feasible. Many vendors, however, now offer EASM solutions to ease users’ minds.