What is External Attack Surface Management (EASM)?

External attack surface management (EASM) is the continuous exercise of managing cybersecurity risks associated with an organization’s external-facing digital assets. The process includes monitoring, identifying, reducing, and mitigating risks present across an organization’s external attack surface.

In other words, EASM strategies help organizations improve their overall cyber hygiene by establishing critical protections for all internet-facing assets and developing protocols to stifle the malicious efforts of threat actors and cybercriminals.

EASM should be a priority for any organization that maintains an extensive digital footprint or manages a sizeable digital supply chain. Implementing EASM principles into its overall cybersecurity program can help organizations detect cyber threats across web applications, misconfigurations, public cloud services, APIS, shadow IT, and other digital assets.

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What is an attack surface?

An organization’s attack surface is the totality of all vulnerabilities, pathways, and attack vectors hackers can exploit to carry out cyber threats or gain unauthorized access to critical networks or sensitive data. An organization’s attack surface includes:

• Known assets: Assets that have been previously inventoried and managed, corporate website, serves, and any dependencies
• Unknown assets: Assets such as Shadow IT or orphaned IT infrastructure that was previously outside the sight of an organization’s security team, including forgotten projects, development websites, or marketing sites
• Rogue assets: Malicious infrastructure created by threat actors or hackers like malware, typosquatting, or a website/application impersonating an organization’s domain
• Vendors: An organization’s attack surface includes the risks its third-party and fourth-party vendor relationships present. Vendors can introduce significant third-party and fourth-party risks, including significant data breaches 

The term “external attack surface” is commonly used to refer solely to the attack vectors associated with an organization’s external-facing assets. Cybersecurity personnel also use the term to differentiate from an organization’s internal attack surface, which includes vulnerabilities derived from internal assets such as firewalls and physical hardware.

External vs. internal attack surface

The difference between an external and internal attack surface lies in the source and location from which potential attacks may originate.

An organization’s internal attack surface includes risks associated with authorized individuals within the organization. In contrast, an organization’s external attack surface is composed of attack vectors external entities can exploit to compromise the organization’s digital assets.

• Internal attacks: Misuse of privileges, unauthorized data access, data theft, and attempts to disrupt service carried out on premises by malicious, negligent, or compromised insiders
• External attacks: Phishing, ransomware, malware, session spoofing, and other attacks carried out externally by hackers or organized cybercriminal groups.

The larger the organization, the bigger its digital footprint and, as a result, the number of potential attack vectors, making enterprise attack surface management especially critical for large businesses.

What is Attack Surface Management (ASM)?

Attack surface management (ASM) is the overarching cybersecurity principle that includes EASM and internal attack surface management. Organizations utilize ASM to manage risks across their internal and external attack surfaces.

Related: Attack Surface Management vs. Vulnerability Management

Components of attack surface management (ASM)

Most comprehensive ASM programs and solutions are composed of five stages:

• Asset discovery: The identification of all Internet-facing digital assets that contain or process sensitive data, such as PII, PHI, and trade secrets
• Inventory and classification: Dispatching and labeling assets based on type, technical characteristics, properties, business criticality, compliance requirements, or owner
• Risk scoring and security ratings: Data-driven, objective, and dynamic measurement of an organization's security posture
• Continuous security monitoring: 24/7 monitoring of critical assets, attack vectors, and known risks and vulnerabilities
• Remediation and mitigation: The process of eradicating unnecessary risks and minimizing the impact of necessary cyber risks

Why is external attack surface management important?

External attack surface management is essential because it helps organizations develop protections to prevent external cyber attacks and mitigate security risks. EASM includes protecting assets like:

• Web applications
• Misconfigurations
• Public cloud services
• IoT and shadow IT assets
• APIS and integrations
• Open-source or outdated software
• Vendor-managed assets

External attacks can stem from a plethora of attack vectors. Any vulnerable endpoint, exposed asset, or security gap in an organization’s IT ecosystem can be exploited by a hacker. Therefore, timely identification of digital assets and ongoing asset inventory maintenance is critical to the health of an organization’s overall threat intelligence and EASM system.

What is an external attack surface solution?

EASM solutions are a combination of cybersecurity tools that utilize automation and software assets to provide organizations insight into the hygiene, orientation, and structure of their external attack surface. These solutions assist organizations with risk identification, assessment, remediation, and mitigation.

The most successful EASM solutions will utilize tools and data points that provide a comprehensive, real-time portrait of an organization’s external assets.

UpGuard Breach Risk is a leading EASM solution integrating continuous monitoring, cyber risk ratings, data leak disclosures and remediation workflows to streamline risk management across an organization's digital footprint.

The importance of continuous attack surface monioring

Continuous attack surface monioring ensures emerging cyber threats are accounted for in a risk management program in real-time. Without continuous monitoring, third-party risks are primarily detected through point-in-time detection methods, such as vendor risk assessments.

With point-in-time methods alone, cyber risks emerging outside risk assessment schedules are not accounted for, leaving an organization exposed to potentially critical third-party data breach risks until the following scheduled risk assessment, which could be months away.

By augmenting point-in-time vendor risk assessments with continuous attack surface monitoring, security teams are instantly alerted of external attack surface changes requiring deeper investigation, events that could trigger additional risk assessments outside of routine schedules. 

One of the most efficient methods of continuous attack surface monitoring is tracking changes in vendor security postures, quantified as security ratings. At a high level, identifying vendors experiencing significant declines in their security ratings makes it easier to track those posing the greatest security risks to your organization. 

Learn more about UpGuards security ratings >

At a deeper level, applying security rating technology to each vendor's risk profile highlights remediation tasks that should be prioritized for the greatest cybersecurity benefits, supporting a more streamlined and efficient Vendor Risk Management program.

Understanding external attack surface monitoring and scanning

External attack surface monitoring and scanning are essential practices in modern cybersecurity, helping organizations identify and manage vulnerabilities in their digital footprint. These processes involve mapping, analyzing, and continuously monitoring all external-facing assets to detect potential risks before they can be exploited.

What Is external attack surface monitoring?

External attack surface monitoring focuses on identifying all the components of an organization’s external-facing infrastructure. This includes websites, applications, IP addresses, cloud environments, and even email domains. By understanding what assets are exposed to the internet, organizations can gain visibility into potential entry points for attackers.

What Is External Attack Surface Scanning?

External attack surface scanning is the proactive process of examining identified assets for vulnerabilities. This involves running automated checks to detect issues such as open ports, outdated software, misconfigurations, and weaknesses in encryption or authentication protocols. These scans provide actionable insights to address security gaps and improve overall resilience.

Why are these practices important?

In today’s interconnected world, organizations are more reliant than ever on external digital systems, including cloud services and third-party tools. However, these systems often fall outside the direct control of internal IT teams, making them prime targets for cybercriminals. External attack surface monitoring and scanning help organizations:

• Identify Unknown Assets: Detect shadow IT or forgotten resources that could become vulnerabilities.
• Reduce Risk: Highlight security weaknesses and allow teams to remediate issues before they are exploited.
• Enhance Compliance: Support adherence to cybersecurity frameworks and regulations by maintaining visibility and control over external assets.

By implementing external attack surface monitoring and scanning, organizations can build a more secure, transparent, and manageable digital presence and safeguard against potential threats in an ever-changing cyber landscape.

Use cases for EASM solutions

Organizations often utilize comprehensive EASM solutions to bolster their risk management procedures (including third-party risk management (TPRM) and Cyber Vendor Risk Management

Some everyday use cases for EASM solutions include:

• External asset discovery‍
• Risk assessment‍
• Attack surface reduction
• ‍Risk mitigation and remediation‍
• Incident response (IR)‍
• Resource allocation

Related: How to choose an EASM tool >

1. External asset discovery

Maintaining an accurate asset inventory can be challenging for most organizations, especially when their external attack surface continues to expand.

The number of new domains present within an organization’s attack surface at any given time will depend upon the business’s unique digital footprint. However, a comprehensive EASM solution will be able to track these new entry points, provide real-time insights into their security, and assist organizations with risk prioritization.

Watch this video to see how an EASM solution like UpGuard can help you map all IT assets in your digital footprint.

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When security teams are informed of all exposed assets in their external attack surface, they are better prepared to carry out other critical cybersecurity workflows, including:

• Threat intelligence
• Vulnerability management
• Vulnerability scanning
• Exposure management
• Penetration testing (pen testing)
• Vendor Risk Management (VRM)
• Attack surface monitoring
• Cyber risk remediation efforts

Learn more about UpGuard’s ASM features and tools >

2. Risk assessments

A comprehensive EASM solution will help organizations achieve accurate risk assessment in many ways. First, a complete EASM solution will improve organizational awareness, providing insights into the risks or vulnerabilities plaguing their external attack surface.

Next, the most comprehensive EASM solutions will rank known risks by criticality, allowing security teams to further define their risk prioritization goals using accurate reports and real-time updates.

In addition, complete EASM solutions like UpGuard Breach Risk will enable organizations to protect their reputation and improve their cyber hygiene. UpGuard empowers its users to proactively address risks to prevent reputational harm before their company ends up in the news headlines for all the wrong reasons.

Watch this video for an overview of UpGuard's risk assessment workflow:

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Attack surface reduction

The overall goal of attack surface reduction is to limit (or reduce) the options attackers have to target an organization’s digital assets or critical networks. There are many ways an organization can reduce its attack surface, including:

• Adopting a zero-trust cybersecurity model
• Installing robust protocols for user access
• Establishing strong authentication habits
• Ensuring strong protections for data and code backups
• Using firewalls to segment their network

EASM solutions can also help organizations reduce their digital attack surface in various other ways. For example, UpGuard helps organizations discover exploitable vulnerabilities and domains at risk for typosquatting. The platform also allows users to detect software vulnerabilities or misconfigurations that could result in malware injections.

Incident Response (IR)

Incident response (IR) refers to the processes and systems organizations have in place to detect and respond to data breaches or other cyber attacks. The best IR programs utilize an incident response plan (IRP) to define how an organization will prevent various types of attacks and mitigate the damage caused by attacks that do occur. Each potential cyber threat that has a possibility of occurring should have unique IRPs outlined to defend against it.

Utilizing an EASM solution can help most organizations improve their IR programs by speeding up the response time of critical personnel and providing deeper insights highlighting previously unknown vulnerabilities. The most comprehensive EASM solutions also give users access to high-level reporting to demonstrate IR progress, necessity, and value to senior stakeholders and other personnel throughout the organization.

Risk mitigation and remediation

A robust EASM solution can help an organization simplify and accelerate its risk remediation and mitigation procedures. Over time, this simplification will also improve an organization’s confidence in its cybersecurity efforts.

UpGuard Breach Risk users can identify vulnerabilities, detect changes, and uncover potential threats around the clock. This preparedness allows users to quickly progress through remediation and mitigation workflows when vulnerabilities and critical risks occur. UpGuard’s risk waiver system enables users to promptly waive extraneous risks, while tailor-made reports provide stakeholder support across departments.

Resource allocation

Resource allocation is an essential principle in all areas of cybersecurity. Organizations that improve the efficiency and accuracy of their resource allocation initiatives are better suited to achieve other protocols across security concepts like asset discovery, risk assessment, attack surface reduction, incident response, and risk mitigation.

By utilizing a SaaS EASM solution like UpGuard, organizations can further define what resources they need and cull expenses that are no longer necessary to achieve their EASM goals. The value of a comprehensive EASM solution begins with the insight and risk identification it provides.

In addition, UpGuard’s flexible reports provide stakeholder support and communicate the need for EASM resources.

How can UpGuard help with external attack surface management?

UpGuard Breach Risk is a leading external attack surface management solution that allows users to streamline their EASM processes and achieve their risk management goals.

Breach Risk’s powerful toolbox of cybersecurity features helps users with:

• Real-time security risk monitoring across your digital footprint
• Continuous monitoring
• Cyber risk remediation
• Data leak detection
• Attack surface reduction
• Stakeholder reporting
• Third-party integrations
• Typosquatting

"UpGuard makes security monitoring effortless. Automated scans and continuous monitoring keep our systems safe without constant manual intervention."

- User in the legal services industry