Every organization has something exposed on the internet that they don't know about. A server someone stood up to meet a deadline and forgot to register. A subdomain from a test environment that never got taken down. An entire digital property that got lost during a merger and now belongs to no one.
These forgotten assets sit waiting to be discovered. The only question is who finds them first: your security team or your adversary?
The reality is that 83% of organizations are unable to clearly identify and inventory their exposed digital assets. This is a dangerous position to be in when 73% of cybersecurity leaders report experiencing incidents due to unknown or unmanaged assets. Simply put, you can't protect what you don't know about—and most organizations don't know where their digital presence begins and ends.
But, if you want to protect your business, your people, and your customers, where do you start?
Terms like Attack surface management (ASM), external attack surface management (EASM), and attack surface intelligence (ASI), blur the lines and are often used interchangeably. However, ASM and EASM serve distinct purposes, while ASI provides a much-needed upgrade that’s essential for organizations facing modern threats.
Understanding these differences isn't just for academics when there are real-world consequences. Choosing the wrong approach—or deploying the right one incorrectly—opens up opportunities for attackers to slip through the cracks.
So, let’s cut through the confusion. Read on for clear definitions of ASM, EASM, and ASI. Discover the core differences that matter for your security strategy, find out when to use each approach, and learn why getting this right has become essential for organizations operating in today's threat environment.
Organizations now live on the internet by default. This means an explosion of assets, infrastructure, and vendors, much of it relying on platforms you don't own, services you rent, and systems that exist far beyond the firewalls you control. Cloud environments, social media profiles, third-party platforms, and domain registrars all play their part in spreading your brand across the internet.
Mergers and acquisitions make matters worse, as assets shuffle between organizations, documentation gets lost, employees with institutional knowledge leave, and properties that once had owners become orphans.
The result is "digital residue" that’s nearly impossible to keep track of manually.
And the internet itself is rapidly expanding thanks to generative AI. Josh Mayfield, Senior Director of Product Marketing at ZeroFox, explains that roughly 50% of internet content is now AI-generated, and that number continues to rocket upwards. But it's not just more content. It's more connections between content, increasing the density of the relationships between pages, services, and applications.
All this growth is an unavoidable component of how modern companies operate, but it creates a Gordian knot of complexity that leaves organizations struggling to understand where they begin and end.
On top of the spreading digital sprawl, the threat environment is intensifying. Traditional cyber threats like phishing, typo-squatting, and impersonations are now turbocharged as AI lowers the barrier for attackers to launch sophisticated campaigns.
For instance, drafting a convincing phishing email in a language you don't speak used to be difficult, so phishing attempts were riddled with grammatical errors. They also used generic, broad-spectrum messages that could only fool a small percentage of readers. Today, freely available AI models can mass-produce professional, well-formatted emails, and personally target them using information scraped from social media to trick victims far more effectively. As Jill Cagliostro, Director of Product Management at ZeroFox, notes, this also frees up threat actors to explore new avenues of attack.
Against this backdrop, regulatory pressure is mounting. The SEC has started enforcing cybersecurity rules, the GDPR applies to most global organizations, and California has introduced new regulations. Organizations have seen unprecedented growth in fines for cybersecurity incidents.
What hasn’t changed is that the math still favors the attacker. While security teams have to plug every hole, threat actors only need to find one. This is the key reason you have to discover your own vulnerabilities first and shift the odds back in your favor.
What’s more, companies no longer need to consider only the threat posed by old school cyber criminals.
"There's been a huge uptick in nation-state activity in the last years, and they're not just going after government entities," says Cagliostro.
"If you are defined as critical infrastructure, which is a fairly expansive definition by the U.S, that's exactly what nation-states target. Financial services, communications, the utility and energy sector, healthcare, all of that counts as critical infrastructure."
"So, even smaller organizations that previously flew under the radar because they just weren't big enough to be a target are now starting to see that activity as well, because hacking's getting easier."
While the attack surface was once confined to internal networks, the scope has expanded well beyond traditional IT assets. It now includes everything in your organization that could be exploited by an attacker—every application, device, account, and network connection someone could target.
Mayfield sums up the attack surface as “all the assets you’ve spun up that are reachable and exploitable.”
“It could be a random host that has some Linux application running on it that someone set up that you forgot about,” he says.
“But it's deeply connected to you because it still hosts your services, applications, and content, and information transfers between you and it, and has your users who are authorized to get into it.”
Cagliostro provides a real-world example of a company that discovered a server they had no record of.
“Perhaps it was one of those things that got lost in transition during an M&A. I'm sure it was probably in someone's spreadsheet in a shared drive at one point, but that information was long gone,” she says.
“But you really don't want to be that guy who finds out about this website that you didn't know you owned because law enforcement knocks on your door and tells you it's serving malware.”
Previously, assets like this might be found through penetration testing that you ran once a year.
“But your teams are standing up websites faster than that now to meet the evolving needs of the business, and threat actors are finding them even faster. So, you can't really wait anymore. You need to always be in a continual discovery approach, or you're going to miss things that are part of your attack surface.”
What’s more, Cagliostro highlights that the attack surface is expanding beyond digital assets and becoming more physical:
“It's not just websites, domains, credentials, the usual suspects, but it's also things like your brand or social media accounts, your physical location, and your executives or even their child’s school,” she says.
“Are there protests going on near your retail stores? Or against your organization?”
"It's also more about physical threats against your people than ever before."
“We're starting to see the risk of your digital attack surface, like sharing a speaking engagement, becoming more of a kinetic threat in business settings, where it's never been like that in my lifetime, and not my parents' either, right? You weren't putting your life on the line by running a company, traditionally. And, unfortunately, that attack profile has changed.”
In a nutshell, the modern attack surface encompasses:
Attack Surface Management is a broad category that asks, "What could someone attack if they were inside or outside our walls?" It covers the full scope of assets an organization needs to protect, both internal and external. That includes:
Mayfield says that, traditionally, ASM focuses on the internal network:
“It looks at those hard assets you know about within your perimeter firewall, the IPs you've documented, the servers you've inventoried, those things that are largely holdovers from a bygone age.”
However, Cagliostro explains that ASM has since come to be used as a more generic term that “applies to just about anything: internal assets, external assets, physical devices, and office locations”.
“But it’s an inherently reactive approach, because attack surface management solutions are focused on the known unknowns.”
“You give them a list of IPs to scan, you tell it what you think your assets are, and it’ll check the vulnerabilities on them, which is very important. But it doesn't do a great job of detecting the unknown unknowns, assets that exist but aren't on any official inventory.”
External Attack Surface Management (EASM) is focused on discovering, validating, and managing digital assets that exist outside your traditional network perimeter, far beyond the firewall, in the external space where businesses must operate but don't fully control.
EASM is best thought of as a security discipline—practices you follow, programs you implement, strategies with projects, goals, and mandates. It’s a specialized component within broader ASM strategy, and the relationship between the two is complementary, not competitive.
Where traditional ASM works from the inside out (you tell it what to scan), EASM provides an "outside-in perspective"—the same view a threat actor would have when looking for ways into your organization. What’s more, it doesn't wait for you to provide a list of assets—it goes looking for anything connected to your organization and surfaces what it finds. Together, they provide broad coverage. Separately, you're left with blind spots that attackers will notice before you do.
EASM finds things like:
“EASM tackles the attack surface you care most about, the real new perimeter, which is much farther out in that E space,” says Mayfield.
“It's external to things that you control. It's on platforms that you don't own like clouds, socials, and other internet systems.”
“That’s why, in today's conversations in most enterprises, it's around EASM, because they want to go to the farthest reaches of the edge attack surface to exert influence and control to keep threats far away, instead of letting them get close.”
“EASM is about putting a security focus on asset management. So the first reason why people really buy it, is for discovering and understanding what their attack surface is. The second is then managing it from there in a prioritized way.”
Cagliostro points to coping with the rapidly expanding attack surface as another advantage of EASM:
“Businesses are growing so fast, and expanding into so many spaces, it's hard for organizations to actually understand themselves, where they exist, and where they're at risk,” she says.
“And so you have to find other ways to find your exposed assets, other than your employees documenting them and hoping everyone follows the process so you can find threats before law enforcement comes knocking.”
However, a lot of organizations struggle with balancing the needs of the business versus the needs of security. Security is often seen as a cost center, and there’s a belief that upgrading it always disrupts business.
“What we also often see is that the security team struggles to communicate the level of risk in a way that the receiving team can understand, right? To them, it just seems like everything's always a fire, and that security's always crying wolf, if you will,” Cagliostro says.
“But, what if you can marry the perspective of what you have, where it sits in your organization, with the likelihood that someone's going to actually exploit it?”
Achieving that synthesis begins with putting risk mitigation systems in place, such as an external attack surface management solution, to increase visibility, protect yourself, and increase efficiency.
“Regardless of the severity of a vulnerability, if there are no known exploits and no threat actors are targeting that kind of asset, it can wait if your business needs it to.”
“However, if you have something that's internet accessible, that a threat actor that's known to target your industry is actively exploiting, and it's on the CISA known exploit list, then you probably want to prioritize that more urgently.“
With an effective EASM strategy, you can show leadership exactly what your external attack surface looks like—with context about which threats are actively targeting which assets—and conversations about prioritization become productive. Business teams can make informed decisions about which systems need immediate attention and which can wait.
“And that improved self-knowledge also helps you operate more confidently in every other aspect of your business to expand into new markets, to develop new services and products, and avoid fines in the process,” Cagliostro adds.
What’s more, EASM helps you to meet compliance obligations by providing robust attestation capabilities that prove what assets you have and what controls are applied.
“Everyone should have EASM, is the crux of it. It's impossible to run a business in today's modern world without leveraging technology, right? And if you're leveraging technology, and you're on the internet, you've got to be aware of where exactly you're on the internet and how that makes you vulnerable.”
Attack Surface Intelligence (ASI) is ZeroFox's specific solution that transforms EASM from a discovery tool into a threat-informed intelligence platform. The key difference is that while most EASM tools stop at visibility and data aggregation—helping teams "study" or "understand" risk—ASI is built to turn observation into action and actually eliminate threats. By fusing EASM with Cyber Threat Intelligence (CTI) and Digital Risk Protection (DRP) in a single platform, ASI finds assets and threats, validates them against billions of signals to filter noise, then actively disrupts bad actors by removing their infrastructure from the internet.
If EASM is comparable to having a high-resolution satellite map of your property that shows every open window, door, and gate, ASI is more like sharing a live satellite feed with a private security force that sees the burglars approaching, knows their specific tools, and instantly boards up the windows and intercepts the intruders before they can step onto your lawn.
Mayfield explains that EASM discovery creates an inventory and a database, but typically lacks the threat intelligence that adds context and enables disruption.
"I would actually caution people not to go down the EASM path unless you're ready with that context to make it meaningful," he says.
| EASM vs. ASI | ||
| Feature | EASM | ASI |
| Primary Goal | Asset discovery and visibility | Threat-informed defense and disruption |
| Scope | Internet-facing infrastructure | Infrastructure + Brand + CTI + Social + Dark Web |
| Methodology | Identification and "studying" risk | Continuous Discover, Validate, Disrupt cycle |
| Action | Alerts and reports | Takedowns and active threat elimination |
| Context | Vulnerability/asset status | Adversary intent and active targeting |
ZeroFox's approach to ASI centers on the three-part methodology of Discover, Validate, and Disrupt. This means that, unlike competitors that stop at visibility, ZeroFox builds each capability to drive action—not just observation. Let’s take a closer look at how it works.
ZeroFox uses reconnaissance techniques similar to those attackers deploy—an army of headless browsers that crawl the internet, clicking every link, seeing what's connected, and scraping everything to understand how each webpage operates, who owns it, and what applications fuel it.
This discovery process finds:
The platform then builds a "living inventory" that adapts as your digital environment changes, using continuous scanning to mirror the recon and discovery behavior of real attackers.
ZeroFox provides a "discovery path" for every asset, showing exactly how the platform found it—whether through a shared SSL certificate, DNS record, or other connection. This visual relationship mapping lets analysts see how assets connect across the ecosystem, speeding up investigations and revealing hidden chains of exposure. By automatically fingerprinting environments, you can identify whether an asset sits in a specific cloud account (AWS, Azure) or belongs to a third-party vendor or partner. This attribution capability addresses one of the biggest headaches in EASM: determining whether a discovered asset is actually yours. Mayfield notes this builds trust into the data because you can see precisely how each finding was attributed to your organization. ZeroFox's AI discovery has reached 99% accuracy in determining asset ownership—approaching human-level discernment and eliminating the tedious manual tasks that plague other solutions.
The platform also captures visual evidence of web-facing assets directly within asset and vulnerability cards. This instant visual context helps analysts quickly spot threats like unauthorized login portals, clone sites designed for fraud, or other suspicious content without leaving the platform.
An inventory without context is just a database, and when everything looks equally urgent, nothing gets prioritized effectively. That’s why ZeroFox fuses discovery with threat intelligence to add the context that fuels action.
Every discovered asset gets enriched with:
And because not every vulnerability carries equal weight. ZeroFox scores and ranks findings by:
Threat intelligence integration and vulnerability ranking let you "play hot and cold" with priorities, as Jill Cagliostro puts it. Threats against asset classes you weren't even tracking can jump to the top of your list if intelligence shows active campaigns against them, while assets you'd worried about might drop lower because the threat landscape has moved elsewhere.
This prioritization cuts through the noise and enables small analyst teams to focus on high-priority issues rather than getting bogged down in lower-risk work.
This is where ZeroFox surges far ahead of competitors. When the platform flags a threat, it doesn't just raise an alert—it provides step-by-step, AI-driven remediation recommendations tailored to each exposure. This guidance is based on years of analyst experience baked into the models, enabling rapid mitigation even for small teams without deep expertise in every technology.
As one satisfied client put it, "ZeroFox EASM AI-based remediation recommendations blow their competition out of the water, delivering immense value to our organization."
ZeroFox also uses its Global Disruption Network to actively remove threats—for example by taking down fraudulent domains, blocking phishing operations, and eliminating impersonation accounts.
ZeroFox disruption actions include:
The choice between ASM vs. EASM, vs. ASI depends on your organization's size, complexity, and what you're trying to accomplish. Here’s a brief guide to what matters when.
Traditional ASM remains essential for internal assets—the servers, endpoints, and network infrastructure behind your firewall. Their vulnerabilities haven't gone away; they’ve just been joined by external concerns that demand additional attention.
If you're a small organization with a manageable footprint, traditional ASM with basic vulnerability scanning may be sufficient. As Cagliostro explains, "If you're just a few people, you can go talk to everyone and confirm no one's standing up websites without telling anyone.” When you can walk down the hall and verify your asset inventory, you don't necessarily need sophisticated discovery tools.
For most of today’s organizations, the digital-first nature of modern business means maintaining confidence in your asset inventory is nearly impossible without dedicated EASM tooling.
For example, EASM means you no longer need to rely on employees correctly documenting every new social account, webpage, or cloud connection. EASM also protects you against threats from a supply chain which likely involves numerous third-party connections across multiple regions with distributed infrastructure.
ASI is necessary for anyone who wants to move beyond visibility and take action. When your challenge isn't just knowing what assets you have, but understanding which ones are actively being targeted and doing something about it, ASI provides that capability.
ASI is particularly useful when:
The ZeroFox approach to ASI addresses not just what assets you have, but the liability and costs associated with potential attacks on those assets, and gives you the tools to prevent them.
As Jill Cagliostro puts it: "That's the ROI—finding that asset before a bad guy or law enforcement does. The alternative is learning about your infrastructure from law enforcement or discovering a breach after the damage is done.”
AI is promoted everywhere these days, and the ASM and EASM spaces are no exception. Many platforms offer end-to-end AI solutions that promise complete external asset discovery, continuous, automated monitoring, and external, agentless operation. However, AI puts a lot of ownership on the consumer to validate, understand, and ultimately process the avalanche of data it provides. ZeroFox leverages AI for scale, speed, consistency, and correlation and the other areas where it performs best. But we also understand its limitations, so we always make sure a human is in the mix.
“Fighting bad actors is as much about psychology as it is technology,” says Cagliostro.
“AI can’t match a human's ability to understand the context of what the threat actor on the other side is trying to do. Our team of industry veterans have been in the threat intel space for as long as it's existed commercially. They know how to put themselves in the minds of the adversary and know exactly how bad guys are trying to exploit organizations. So, they can find things better than AI or even other people.”
This level of expertise allows ZeroFox threat intel analysts to read between the lines and work backwards to get ahead of bad actors.
“It's a cat-and-mouse game. The second you figure out how to stop one adversary tactic, they're going to move on to another,” Cagliostro says.
“But because we have an intelligence team that is constantly operating in the dark web and conducting research, we're able to keep pace with the changing attack vectors in a way that most organizations can't, because they don't have the information. But we do, and we can deliver those insights back from technology to an end user.”
To ensure intelligence converts directly into action rather than accumulating in a separate system, the platform connects into existing workflows by providing integrations with:
Measuring success in attack surface management can be challenging because it often involves “proving a negative,” or demonstrating that, because an attack did not happen, your organization is now safer. However, there are specific metrics and strategic outcomes you can use to define success and demonstrate a Return on Investment:
Organizations using ZeroFox EASM report measurable improvements in Mean Time to Detect (MTTD) and Mean Time to Respond (MTTR). For example, one multinational luxury goods company reported a significant drop in detection and response times for external vulnerabilities. AI-based remediation can slash MTTR from 18 days to just 5.
Traditional EASM discovery often produces fuzzy results. A tool might see an IP address close to your ASN block range and conclude the asset is "probably" yours. But if 29% of discovered assets turn out to be false positives, you won't know which 29% until you've manually reviewed everything.
As Josh Mayfield notes: "That is a time suck, but it's eliminated with our AI discovery." ZeroFox's AI discovery has reached 99% accuracy in determining asset ownership—eliminating the cleanup headache that plagues new deployments.
With ASI streamlining workflows and unifying visibility, security teams operate more efficiently. Our multinational luxury goods client manages hundreds of websites across multiple brands and found that consolidating tools into a single platform simplified operations and let their small analyst team support fix teams across the organization. A large financial institution integrating the ZeroFox platform with Vulcan can expect to see a 60% drop in redundant findings.
High-profile breaches make headlines for all the wrong reasons and destroy customer confidence. So, managing your external attack surface helps safeguard reputation and maintain customer trust.
EASM capabilities address threats like counterfeit products, social media impersonation, credential leaks, and fraudulent domains that damage brand integrity. When you prevent incidents, stakeholders can see their data and interactions remain secure.
Organizations implementing continuous threat and exposure management—for which ASI is the starting point—are three times less likely to suffer a breach. Gartner predicts that in 2026, organizations prioritizing security investments through this approach will see a two-thirds reduction in breaches.
A better security posture doesn't just prevent bad outcomes, it enables growth. Understanding your attack surface lets you take calculated risks rather than flying blind. For example, EASM helps evaluate the digital risk profile of potential acquisitions before integration and surfaces inherited exposures afterward. You can move fast without leaving doors open behind you.
Modern businesses depend on complex webs of partners, suppliers, and vendors—each with their own systems connecting to yours. EASM helps verify that external partners meet security standards and identifies connection points that could introduce supply chain vulnerabilities.
EASM and ASI let you monitor SSL certificates across domains and alerts you when they're expiring—protecting both security and customer experience. It also identifies server misconfigurations, open ports, and risky services that create exposure.
Threat actors constantly target organizations with spoofed domains, fake websites, cybersquatting operations, and fraudulent social media accounts. With ASI and EASM you can identify brand impersonation and counterfeit operations that steal revenue and damage reputation.
ASI and EASM can find attackers hosting your content on their phishing servers, detect suspicious connections between your legitimate marketing systems and unknown servers, and flag content cloak operations that let criminals pass as you.
EASM integrated with threat intelligence monitors for compromised credentials appearing on the dark web. The disruptive approach goes beyond alerting—automatically triggering password resets when customer credentials are exposed.
By correlating discovered assets with threat intelligence—including CISA's Known Exploited Vulnerabilities list, active threat campaigns, and real-world attacker behavior—you can prioritize which vulnerabilities to patch first.
EASM creates an inventory of externally visible software across your organization. You can then monitor for known vulnerabilities and exploits specific to that software, track chatter on the dark web about threat actor groups targeting it, and see how you're impacted when new vulnerabilities emerge.
Monitoring for non-standard ports can reveal threat actor activity. This is especially valuable when attackers create subdomains that were never registered, making them invisible to traditional security tools.
In a threat landscape that has become more personal and more physical, ASI monitors for threats made against executives online, giving organizations time to respond before digital threats become kinetic.
Regulations like GDPR, SEC cybersecurity rules, and NYDFS requirements legally require businesses to secure their data and prove they've done so. ZeroFox provides attestation capabilities—demonstrating what assets you have and what controls are applied.
"You think you're compliant, we'll see if you really are, and prove it,” Mayfield says.
“The attestation part, that's where ASI comes really handy."
The bottom line is that figuring out the key differences between ASM vs. EASM vs. ASI is valuable for building an effective security strategy.
But the practical reality is that these aren't generally either/or options. Trust ASM to handle your internal assets, use EASM to discover your external footprint, and leverage ASI to weaponize that discovery with threat intelligence and disruption capabilities. For most organizations, the question isn't which one to use, but how to layer them appropriately based on where your greatest risks lie.
ZeroFox delivers robust ASM, EASM, and ASI using its Discover, Validate, Disrupt methodology. The platform doesn't just surface your external attack surface—it enriches findings with real-world threat intelligence, prioritizes based on actual adversary activity, and actively eliminates threats through its Global Disruption Network.
As Jill Cagliostro puts it: "Unlike competitors, we don't just tell you about a problem, we help you fix it."
“Organizations can trust ZeroFox for their attack surface intelligence and beyond because we've been doing this for forever. We know what we're doing.”
Ready to see your attack surface the way attackers do, and stop threats before they start? Learn how ZeroFox can help you discover your unknown exposures, validate which ones matter most, and disrupt the threats targeting your organization.
