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What Is Attack Surface Management (ASM)? Complete Guide and Best Practices

Have you ever wondered how hackers actually break into companies?

Most of the time, it’s something shockingly boring. They just find something exposed that no one noticed. And that’s worse than it sounds.

In fact, in 2024, IBM reported that the average data breach cost businesses $4.45 million.

reports average data breach
Source: cyberunit

One of the best ways to be proactive with cyber defense is with an Attack Surface Management (ASM) program. It’s like walking around the house every day, checking every entry point before someone else does.

Sounds obvious, right? But you’d be surprised how many companies skip it or difficult to keep with as different business units procure services or spin up assets.

So, to make sure you don’t do that to your company, here’s what attack surface management is and everything else you need to know about it.

What is Attack Surface Management (ASM)?

Attack Surface Management strategy is the continuous process of discovering, analyzing, and monitoring all the possible points in a system where an attacker could gain access. This includes exposed servers, misconfigured cloud storage, and even outdated software. This is your attack surface.

Let’s simplify this for you.

To simplify the attack surface management definition, think of your digital world as a castle. Your attack surface is every possible door, window, tunnel, or secret passage someone could use to sneak in. And with cloud tools, remote work, and endless SaaS apps, that castle is now huge.

ASM is the process of walking the perimeter every day, finding new openings, fixing weak spots, and staying ahead of intruders.

Why is this such a big deal?

Because, according to a cybersecurity report, 70% of successful breaches started with unknown or unmanaged assets. Even worse news, in the first half of 2025 0-day and 1-day exploits have increased putting an even stronger emphasis on knowing your assets and patching quickly.

Today’s attack surfaces extend far beyond traditional data centers. Driven by remote work, cloud adoption, and third-party partnerships, organizations now face a sprawling digital footprint across the internet. These dispersed assets create ideal conditions for attackers seeking to exploit overlooked vulnerabilities.

What is CAASM? How does it relate to ASM? CAASM v. ASM?

If you are exploring ASM strategies and solutions, you may also come across the acronym CAASM and you’ll learn that they are related, but not quite the same. CAASM is commonly thought of as all assets, internal and cloud and ASM is largely thought of as external assets.

Cyber Asset Attack Surface Management (CAASM) is a modern cybersecurity approach that gives organizations unified, real-time visibility into all their cyber assets—across on-premises, cloud, and hybrid environments. It provides real-time, unified visibility of all cyber assets—including devices, applications, cloud resources, and users—across on-premises, cloud, and hybrid environments. It pulls data from existing tools (CMDBs, EDR, CSPM, vulnerability scanners, IAM, etc.) to create a centralized, queryable inventory.

CAASM goes beyond traditional asset inventory tools by enabling continuous asset discovery, contextual risk analysis, and automated workflows. This helps IT and security teams quickly identify blind spots, reduce exposure, and strengthen overall security posture.

Check out how we helped Pima Community College with Attack Surface Management.

What Makes Up an Organization’s Attack Surface?

Your attack surface is basically every way someone could try to get into your systems. It includes everything that’s connected to the internet, anything running on your network, and even tools or services you didn’t know your teams were using.

And the more your company grows, the bigger that surface gets. Let’s break down the main parts of it:

1. Public-Facing Web Servers

These are your websites, login portals, and anything visible on the internet. If it’s live, it’s a target. Even a simple misconfiguration or unpatched system can give attackers a way in.

2. Cloud Storage

Things like Amazon S3 buckets or Azure blobs are great for storing files and running apps. But if they’re misconfigured, and many are, they become wide open to the public. Some companies have leaked millions of records this way through third-party data breaches.

3. APIs and Microservices

Modern apps rely on APIs to connect everything. But every exposed API is another entry point. If one isn’t secured properly, it could expose sensitive data or allow unauthorized access.

4. Remote Employee Endpoints

With remote work becoming the norm, employee laptops, phones, and personal devices (BYOD) are part of your attack surface. If someone’s home Wi-Fi is weak or their laptop lacks updates, that’s a potential access point.

5. Shadow IT

This refers to tools or software teams use without telling the IT department. Think of someone spinning up a Trello board, Google Form, or using an AI tool that stores sensitive data. If it’s not tracked, it’s not protected.

6. Third-Party SaaS Tools and Integrations

The tools you rely on every day, such as CRMs, analytics platforms, and email tools, all add to your attack surface. If one of those vendors gets breached, your data could be at risk too.

Are You Sure You Know Everything That’s Exposed?

Most breaches start with something no one saw coming. FortifyData’s Attack Surface Management helps you discover, monitor, and secure every digital asset before attackers do.

Attack Surface Management Lifecycle: How It Works

Let’s understand how attack surface management works behind the scenes when a company takes it seriously. In short, it’s a living process that helps security teams stay ahead of threats in a world that changes every single day.

 

1. Discovery: You Can’t Protect What You Don’t Know

Discovery is the process where your organization examines every digital corner to discover what it actually has out there.

Surprisingly, a lot of companies don’t have a full inventory of their public-facing assets. In fact, in a recent report, 67% of the organizations said they saw their attack surface expand in recent years.

Attack surface management statistics also show that only 29% of them had any visibility over their assets that are connected to the company network. 

This stage includes finding:

  • Known assets like your main websites and APIs
  • Unknown or forgotten assets, like test servers, old subdomains, or unused apps
  • Misconfigured cloud services (like Qualys cloud platform)

Attack surface management platforms use active and passive scanning techniques to do this. Active scanning probes the systems directly, like a flashlight searching for gaps. Passive scanning watches network behavior quietly.

 

2. Classification: What’s Important and What’s Just Noise? 

Once everything’s found, it’s time to organize. Because not every asset is a high-level threat. For example, your customer login page is a bigger risk than an old test site with dummy data.

That’s where classification comes in. ASM tools help break this down by:

  • Identifying which assets are public vs private
  • Fingerprinting the assets and flagging which ones contain sensitive data (like login portals, databases, or admin dashboards)
  • Grouping assets by function (web apps, APIs, user endpoints, etc.)

This step is about context and how to help automatically segment which assets are more critical to business operations than others. It helps security teams focus on what actually matters, rather than wasting time on low-risk issues.

 

3. Prioritization: Fix the Big Holes First

Here’s where things get practical. You’ve got a list of exposed assets.

Now what?

Well, not all risks are created equal. A forgotten subdomain with no traffic is not the same as an unencrypted API that connects to customer data. ASM tools rank these exposures using risk scores that consider four main things:

  • How exposed the asset is
  • How critical it is to your business
  • How likely it is to be exploited
  • Are there active KEVs or CVEs associated with the asset and in use by an APT group

This is where ASM really saves time. It tells your team, “Here’s what’s dangerous, and here’s what can probably wait.”

According to IBM’s 2024 X-Force Threat Intelligence Index, attackers today spend an average of just one week from finding a vulnerability to exploiting it. That’s not much time. Prioritization helps security teams beat that clock.

attackers today

4. Monitoring: Because Things Change Overnight

Discovery and classification aren’t one-time tasks. Your digital environment is always changing. So, ASM tools keep monitoring 24/7.
Every time something new pops up, like a newly launched feature, a third-party integration, or a forgotten endpoint, your ASM system spots it. It’s like having a digital security camera watching your perimeter at all times.
When something important changes, it sends alerts. These can be delivered straight into Slack, email, or connected systems like SIEM or ticketing platforms. That way, your team gets the heads-up before an attacker does.

5. Remediation: Close the Gaps, Fast

Now that you know what’s out there and what’s risky, it’s time to act.

Remediation is where you actually fix the weaknesses. Sometimes that means patching a system, disabling an unused server, or fixing a cloud misconfiguration. Other times, it’s about applying encryption, updating firewalls, or removing public access from sensitive files.

Most modern ASM platforms also integrate with tools your team already uses, like Jira or ServiceNow, so security fixes can be tracked just like any other task.

And here’s a reality check for you. The average time to contain a data breach is 73 days, according to IBM’s 2024 report. But companies with strong ASM processes cut that time in half.

Faster fixes = fewer losses.

time to identify and contain
Source: Govtech

Four Attack Surface Management Platforms (2025 Edition)

With attack surfaces growing every day, choosing the right ASM tool can make a big difference in how fast you detect risks. Here’s a quick look at four of the top Attack Surface Management platforms in 2025 and what sets them apart:

1. FortifyData Attack Surface Management Platform

FortifyData demo

Organizations that extensively implement security automation and AI save an average of $2.2 million per breach compared to those that don’t.

FortifyData offers a full Attack Surface Management solution with real-time discovery, continuous monitoring, and smart risk prioritization.

What makes it stand out is how fast it identifies unknown assets, including shadow IT and third-party risks, and how clearly it maps them into a clean, visual dashboard.

It’s handy for security teams that want deep visibility without drowning in noise. FortifyData also integrates easily with SIEMs and ticketing systems to speed up response times.

Get a Free ASM Assessment

2. Microsoft Defender EASM

Built into the Microsoft Defender suite, External Attack Surface Management (EASM) is ideal for organizations already in the Microsoft ecosystem.

It helps security teams identify internet-facing assets and misconfigurations across domains, cloud services, and endpoints. One of its strengths is the seamless connection with other Microsoft tools like Sentinel and Purvie.

3. Palo Alto Cortex Xpanse

Xpanse is known for its ability to scan the entire internet and identify assets from the outside. It provides real-time insights into unknown or forgotten systems.

Moreover, it prioritizes exposures by risk level and helps automate responses with integrations. For enterprises with large digital footprints, Xpanse brings visibility that’s hard to match.

4. CyCognito

CyCognito takes a unique approach by focusing on attacker-exposed assets, not just known ones. It maps your attack surface across subsidiaries, vendors, and even M&A targets, helping security leaders uncover blind spots before hackers do.

Its automated risk scoring and context-rich asset profiles make it a strong choice for companies dealing with complex third-party ecosystems.

Best Practices for Attack Surface Management (ASM)

Knowing what ASM is and why it matters is a great start, but actually doing it well is where the real security gains happen. Below are some of the best practices every organization should follow to make sure its Attack Surface Management program is effective.

1. Treat ASM as a Continuous Process

Attack surfaces can change daily. New tools get added, employees spin up test environments, cloud apps update silently, and new vulnerabilities or exploits are discovered. That’s why attack surface management should be running 24/7, not just during quarterly audits.

Use an ASM platform that supports continuous identification, monitoring, and alerting. Set regular review cadences to go over what’s new, what’s changed, and what needs immediate attention.

Look for an ASM provider that can identify all your assets and assess all ports and services. Not a passive assessment of the most common ports, we’re talking about all 65,535 ports and services.

2. Reducing Your Attack Surface

Once you’ve gained visibility into your digital footprint, the next step is reducing it. Not every exposed asset needs to stay online—and each one is a potential doorway for attackers. Attack surface reduction means eliminating what’s unnecessary: shut down unused services, close open ports that no longer serve a function, and decommission domains or infrastructure that’s no longer active you’d be surprised at how many times we experience clients with unmaintained DNS records. The smaller and more intentional your exposed surface is, the harder it is for adversaries to find a way in.

Key Practices for Effective Attack Surface Reduction

Track DNS and Certificate Activity
Keep a close eye on new domain registrations and renewal expirations, SSL/TLS certificate expirations, and lookalike domains that may signal phishing or impersonation attempts. These are common blind spots attackers exploit to hijack trust and intercept communications.

Enforce Strong Patch and Configuration Hygiene
Many breaches occur due to unpatched systems or default configurations. Maintain a consistent, disciplined process for applying security updates and hardening internet-facing systems against known vulnerabilities.

Review Access and Eliminate Shadow IT
Overprovisioned user access and unsanctioned tools widen your attack surface. Conduct regular audits of user permissions, remove dormant accounts, and implement identity and access management (IAM) best practices to maintain control.

Embed ASM in Zero Trust and DevSecOps
Attack surface management should inform how you build and secure technology. Feed ASM findings directly into DevSecOps pipelines to address risks earlier in the lifecycle, and align with zero-trust principles to limit exposure and prevent lateral movement.

3. Involve Multiple Teams, Not Just Security

ASM isn’t just the security team’s job. DevOps, IT, cloud teams, and even marketing (yes, really) often launch new tools or web assets. If they’re not communicating, your attack surface management program or system won’t have the full picture.

Build a cross-functional response team and educate departments on the importance of reporting new digital assets. Make security a shared responsibility.

4. Prioritize Based on Risk

It’s easy to get overwhelmed when you suddenly discover hundreds or thousands of assets. But not all of them are urgent. Some are harmless, while others could lead to a breach tomorrow.

Once you’ve mapped out your organization’s digital assets and identified where they’re exposed, the next step is to determine which risks deserve your immediate attention. This means analyzing each vulnerability or misconfiguration to understand where an attacker would most likely focus. Apply business context to assess what could cause the most disruption—put yourself in the mindset of a threat actor to prioritize your defenses effectively.

Enrich with threat intelligence and correlate exposures with known threats
The FortifyData ASM platform has many threat intelligence feeds that map vulnerability databases and feeds to your discovered assets to uncover any known exploits. This helps you identify which exposures are actively being targeted in the wild.

Weigh technical issues against business impact
Not all vulnerabilities are equal. A flaw on a low-traffic microsite may be far less critical than the same flaw on a customer portal or internal application tied to sensitive data. Context is key when assessing risk.

Identify and classify critical assets
Evaluate assets based on sensitivity, business function, and exposure. High-value systems that are publicly accessible—or reachable without strong authentication—should be treated as high-risk. With FortifyData you can assign business criticality to assets via auto-discovery or individual management based on the type of data being stored, transmitted or processed on specific assets. This is continuously updated to produce a risk-based remediation prioritization list, with recommended actions, of the most critical risks.

Prioritize with risk scoring tools
Use automated tools that assign contextual risk scores to vulnerabilities and assets. This enables your team to focus efforts on the most impactful issues, especially when resources are limited. With FortifyData we have built in risk-scoring components to automate this process without having to engage yet another tool.

Use risk scoring to focus on high-value exposures. Look at asset sensitivity, public accessibility, and potential impact before reacting. Fix what matters most, first.

5. Map Third-Party and Shadow IT Risks

organizations experience breaches due to third party exposure

According to a Gartner report, 45% of organizations experience breaches due to third-party exposure. And most businesses have shadow IT tools in use that they don’t even know about.

It’s best to use Attack surface management tools that specialize in identifying third-party, subsidiary, and shadow assets. Also, review vendor exposure regularly and remove any unused services immediately.

6. Integrate ASM Into Existing Security Workflows

Attack surface management framework works best when it’s plugged into your current processes, like ticketing, SIEMs, incident response platforms and management reporting. That way, when something risky pops up, it flows into the same system your teams already use.

Coordinate teams and workflows: Establish clear ownership for handling asset discovery alerts, managing risk evaluations, and responding to changes across IT, security, and DevOps. Aligning people and processes ensures efficient triage and reduces gaps in coverage. Automate alerts and ticket creation through platforms like Jira, ServiceNow, or Splunk. This shortens response time and makes tracking easier.

Incorporate ASM into existing security operations: Connect attack surface management with your existing security techstack—ingest findings into SIEMs, SOAR tools, incident response workflows, and DevSecOps pipelines. This integration ensures discovered risks are actioned promptly, not lost in isolation.

Track performance and refine over time: Monitor metrics like asset discovery speed, time-to-remediation, and recurring misconfigurations. Use this data to track performance improvements, uncover bottlenecks, and build a case for continued investment in attack surface reduction initiatives.

7. Don’t Ignore the Human Factor

Humans still make mistakes. In fact, 74% of all breaches involved the human element, whether through errors, social engineering, or misuse of privileges. That means nearly three out of four breaches could have been prevented with better human awareness.

Train teams to understand ASM basics. Provide simple playbooks or checklists to help them spin up new digital assets or make sure they understand your company’s process for procurement new vendor services. Make secure behavior part of your company culture, not just your tech stack.

Don’t Wait for an Attack to Show You What You Missed

If there’s one thing the modern threat landscape has made clear, it’s this: you can’t protect what you don’t know exists. Attackers aren’t waiting for your security team to catch up. They’re already scanning your external assets, probing for shadow IT, and watching for exposed ports.

However, if you’re not sure where your exposures are or how to prioritize them, that’s not just risky, it’s dangerous. But you don’t have to figure it out alone.

Why FortifyData for Attack Surface Management

Continuous, contextual awareness of an entire external attack surface is table stakes for today’s cybersecurity leaders.. FortifyData’s ASM platform delivers real-time discovery, risk prioritization, and remediation guidance to help security teams stay ahead of threats. Unlike static tools or periodic scans, FortifyData continuously monitors your internet-facing assets and surfaces the exposures that matter most to your business.

Key Benefits of FortifyData ASM:

  • Continuous Asset Discovery: Automatically identifies domains, IPs, subdomains, and exposed services across your entire digital footprint—including shadow IT.
  • Risk-Based Prioritization: FortifyData combines threat intelligence, exploitability, asset value, and considers compensating controls to prioritize vulnerabilities that pose real risk.
  • Live Data, Not Snapshots: Scans are conducted weekly or more frequently to provide up-to-date visibility, new asset identification and changes into new exposures.
  • Integrated Remediation Guidance: Each finding includes actionable steps, helping teams close gaps quickly and efficiently.
  • Modular & Scalable: Easily integrates with internal vulnerability data and other FortifyData modules (like TPRM or Compliance Management) for a broader security view.
  • Supports GLBA, NIS 2 & Other Regulations: Helps organizations comply with regulations that require visibility and management of externally exposed systems.

“It’s an easy tool to use to get a holistic look from an attack surface standpoint, which at the end of the day attack surface is your biggest vulnerability, that’s what your trying to protect. There’s one thing to have a tool to have a tool that gives you information you do nothing with, it’s a whole other thing to get a tool that gives you information you can take action on, it’s making us better.”

Isaac Abbs, CIO, Pima Community College

FortifyData’s Attack Surface Management platform was built for the challenges of attack surface management.

With FortifyData, you can discover every exposed asset across your digital footprint and know precisely where you’re vulnerable.

Schedule a demo today!

FAQs

Use automated ASM tools like FortifyData to continuously scan for all external-facing assets, including forgotten domains, servers, or third-party integrations. These tools uncover what’s publicly accessible, even shadow IT, so nothing slips through the cracks.

Yes. Traditional scanners rely on known IPs and systems, but ASM discovers unknown assets too. It provides a hacker’s view of your environment and monitors constantly, helping you reduce risks before vulnerabilities are even exploited.

Once isn’t enough. Threats change daily. Use a solution that performs continuous, real-time discovery and scanning. This helps you detect risky exposures immediately and stay ahead of evolving attack tactics.

Pen tests are point-in-time and often scoped, but designed to identify the exposures in your attack surface and then penetrate them to learn what other information they can gather, move laterally to other systems or identify what other havoc that they can cause.. ASM is continuous and wide-reaching, showing your full external exposure at all times. Think of it as having a persistent hacker’s view without the risk.

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