A public-facing web application, a forgotten cloud workload, a remote-access portal created for a supplier, an exposed storage bucket or an old subdomain can all become routes into the business.
In context: external and internal attack surfaces
This article focuses mainly on the external attack surface: the domains, applications, cloud services, remote-access systems and other assets attackers can identify and reach from outside the organization.
But the wider attack surface also includes internal systems, identities, network connections, software weaknesses and business processes. External attack surface management is therefore one part of a broader exposure-management program, alongside vulnerability management, identity security, application security and network segmentation.
The value of external ASM is that it helps organizations identify the routes an attacker may use to gain an initial foothold – before that exposure leads to internal access, disruption or data loss.
Some are documented and actively managed, while others sit outside formal asset inventories, belong to recently acquired companies, or were created for a short-term project and never properly retired.
Attack surface management, or ASM, helps organizations find these exposures before an attacker does.
ASM is not a one-off scan or a long list of technical findings, but a continuous process for discovering externally visible assets, understanding which ones matter, reducing unnecessary exposure.
What is attack surface management?
An attack surface is the set of points where an attacker can potentially enter a system, cause an effect or extract data. In today’s enterprises, this extends far beyond the corporate network. It can include:
- Internet-facing applications and APIs
- Domains, subdomains and DNS records
- Public IP addresses and open ports
- Cloud workloads, storage and management interfaces
- Remote access services, such as VPNs and virtual desktop gateways
- SaaS applications and third-party integrations
- Exposed development environments and code repositories
- Credentials and other sensitive information that has been leaked or published online
- Connected devices and operational technology systems that are visible from the internet.
This exposure is far from theoretical. According to Kaspersky research, exploitation of public-facing applications accounted for nearly 44% of the initial attack vectors observed in 2025, making it the most common route into affected organizations.
Attack surface management is the discipline of discovering, assessing and reducing these exposures from an outside-in perspective. So instead of asking, “What does our CMDB (configuration management database) say we own?”, it asks, “What could an attacker identify, reach or exploit?”
This is important because while internal asset inventories are essential, they may not capture cloud services deployed outside standard processes, abandoned domains, unmanaged SaaS accounts, temporary systems or infrastructure created by third parties.
Why is attack surface management important?
Digital businesses never stand still. Infrastructure changes every day as teams deploy new applications, move workloads between cloud providers, connect suppliers, open remote access, launch regional websites or integrate acquired businesses.
This creates an operational problem: the organization’s view of its estate can become incomplete quickly.
Security teams may know about core systems but lack a reliable picture of externally visible assets across business units, cloud accounts, development teams and third-party environments. This can leave unknown or poorly controlled systems exposed for far longer than intended.
Attackers don’t need an organization chart, an approved asset list or permission to look. They use public information, internet scanning, certificate records, DNS data, exposed services and leaked information to build their own picture of the environment.
Attack surface management gives defenders a way to do the same thing first, and more systematically.
For CISOs, the value is not just better visibility, but a more credible basis for risk decisions. Teams can identify which exposed assets support critical services, which lack clear ownership, which are unnecessarily accessible from the internet and which deserve immediate attention.
How effective attack surface management works
Effective ASM follows a repeated cycle rather than a single project.
1. Discover what’s visible
The first step is to build an external view of the organization.
This typically involves identifying domains, IP ranges, cloud services, exposed applications, certificates, open ports, public code repositories and other internet-visible infrastructure associated with the organization. Discovery should include subsidiaries, regional entities, acquired companies and known third parties where appropriate.
A useful starting question is: “Which assets would surprise us if an attacker found them?”
2. Validate ownership and business purpose
Not every discovered asset belongs to the organization – some may be parked domains, former suppliers, shared services or infrastructure belonging to another party. Others may belong to the organization but have no clear owner.
This is where ASM becomes an operating process rather than a technical exercise. Security teams need a practical way to confirm whether an asset is legitimate, who owns it, why it’s exposed and whether that exposure is still necessary.
A remote-access portal may be critical to a supplier relationship, a development server may be required for a time-limited project, a test application may have been left online after launch. The right response is not automatically to shut everything down but to make exposure deliberate, controlled and accountable.
3. Assess the exposure, not just the vulnerability
A system does not need a critical CVE to create risk. An administrative interface exposed to the public internet may be a concern even when fully patched, a cloud service may be accessible more broadly than intended, a login page may reveal too much information to support credential attacks, and a forgotten domain may be vulnerable to takeover or impersonation.
4. Prioritize according to business impact
Prioritization is where many ASM programs either become useful or fail.
A big organization may uncover hundreds or thousands of exposed assets, but it’s neither possible nor necessary to treat each finding as a crisis. The focus should be on exposures that combine technical weakness with meaningful business consequence.
For example, an exposed test server may be low risk if it contains no sensitive data, is isolated from production and is scheduled for decommissioning. An exposed remote-access gateway supporting distribution operations, by contrast, may demand immediate review even if it has no known critical vulnerability.
A practical prioritization model considers the following:
- Exposure: How visible and accessible is it?
- Exploitability: How easily could an attacker use the exposure?
- Criticality: What business process, data or service does it support?
This helps security leaders translate technical findings into decisions that business owners can understand.
A practical example: an exposed remote-access service
Consider a manufacturer that discovers a remote-access gateway connected to a regional operational environment. The service was set up several years ago to allow a maintenance provider to support equipment remotely. It’s still internet-facing, uses a legacy authentication method and has not been reviewed since the provider contract changed.
An ASM process would not stop at reporting that the gateway exists. But it would establish:
- Who owns the service
- Whether the supplier still requires access
- Which systems can be reached through it
- Whether multi-factor authentication is enabled
- Whether access is restricted by network location, time or user role
- Whether activity is logged and monitored
- Whether the service can be removed, replaced or segmented
The business decision may be to retire the gateway, require more controlled supplier access, restrict it to approved maintenance windows or place it behind stronger authentication and segmentation controls.
The outcome is not simply a closed technical ticket. It’s a reduction in the organization’s exposure to operational disruption.
How ASM works with vulnerability management, XDR and threat intelligence
Attack surface management is most useful when it connects with the rest of the security program.
Vulnerability management identifies, prioritizes and helps remediate known weaknesses in the systems the organization can already assess. ASM helps identify the systems, services and cloud assets that may not yet be visible to that process.
Threat intelligence adds context. It can show whether a particular technology, exposed service or credential type is actively being targeted by cybercriminals or associated with a known campaign. That helps teams decide which findings should move to the front of the queue.
XDR, SIEM and other SOC tools help teams detect and investigate suspicious activity across endpoints, networks, cloud environments and other IT systems. ASM can improve their effectiveness by highlighting the external assets most likely to become attack entry points.
Incident response and compromise assessmentservices can also play a role where teams suspect that an exposure has already been exploited, or need an independent investigation to establish what has happened.
Security assessment services simulate adversary behavior, showing how real attackers could exploit applications, networks and devices, providing deeper visibility into the organization's attack surface and helping reduce security exposure.
The point is not to create another isolated security tool, but to connect exposure management with detection, response, asset ownership and risk governance.
How to build an ASM program that results in action
A workable ASM program starts with ownership, not a dashboard.
Security teams should agree how discovered assets will be assigned, validated and remediated. This normally requires participation from infrastructure, cloud, application, network, procurement, legal and business teams.
Five operating principles help:
- Treat asset ownership as a security control. Every significant exposed asset should have a named owner (although this usually happens outside of ASM).
- Link findings to existing workflows. ASM findings need to reach the teams that can fix them, using service-management, vulnerability-management or risk-management processes already in place.
- Measure reduction, not just discovery. A growing asset count may indicate better visibility, not worsening security.
- Report in business terms. Boards and executives do not need a list of ports and certificates. They need to understand where external exposure could affect customer services, operations, regulatory obligations, revenue or recovery capacity.
How ASM turns visibility into risk reduction
Even a mature ASM program doesn’t promise that every exposed system will disappear – businesses need internet-facing services to sell, support, connect and operate.
A strong ASM program is more about discipline:
- The organization knows which externally visible assets it owns
- It can distinguish legitimate exposure from accidental exposure
- High-risk findings have clear owners, defined response times and business context
- Unnecessary services are removed
- Essential services are protected, monitored and reviewed
- And security leaders can demonstrate that exposure is being reduced in areas that matter most.
This is the practical value of attack surface management – not an abstract picture of risk, but a continuous way to make the organization harder to find, harder to enter and harder to disrupt.
Sources and further reading
- Kaspersky Security Assessment portfolio
- NIST Computer Security Resource Center
- OWASP Attack Surface Analysis Cheat Sheet
- Kaspersky Compromise Assessment
- Anatomy of a Cyber World: Global Report by Kaspersky Security Services 2026
- Kaspersky Threat Intelligence
- Kaspersky Managed Detection and Response
- Kaspersky Incident Response
- Kaspersky Services
