What is External Attack Surface Management (EASM)?

External Attack Surface Management (EASM)

Mapping and monitoring your entire attack surface effectively requires advanced tools. An excellent EASM solution should enable users to identify malicious assets within their digital footprint while providing valuable business context insights that aid threat detection and remediation processes.

Cybercriminals are constantly searching for entryways into your internal systems. Without visibility into your attack surface, your data and accounts could become vulnerable and costly consequences could ensue.

What Is External Attack Surface Management EASM?

An organization’s attack surface represents potential entry points for attackers and requires careful attention in managing. By employing EASM tools, businesses can uncover hidden assets while mitigating risks from attacks.

“Attack surface” refers to any digital asset that allows malicious actors to gain entry to an organization’s networks and systems – including third-party suppliers, cloud services, work from home setups, IoT infrastructure etc. Attackers use these expanded attack surfaces to steal sensitive information, breach defenses, inflict financial and reputational damage on victims, as well as stealthily gain entry through backdoors into these assets.

Detectify’s EASM solution automates the process of discovering and mapping an organization’s external attack surface, enabling security teams to identify unanticipated risks and vulnerabilities and combat threats that extend beyond corporate firewalls. EASM should form part of any comprehensive cybersecurity program and should work alongside tools like vulnerability scanners and cloud security posture management; however, EASM should not be confused with Cyber Asset Attack Surface Management (CAASM), which takes an inclusive approach towards risk identification across their entire landscape, including internal assets.

What is the attack surface?

Attack surface management involves the process of identifying, assessing, and mitigating vulnerabilities in externally exposed digital assets like remote access systems, SaaS applications, and cloud infrastructure which are capable of providing access to attackers unauthorized entry. This poses a great threat to organizations as attackers can bypass traditional defenses to gain entry and steal sensitive information or disrupt services without incurring significant cost to themselves or disrupt services further.

Attackers are always searching for an easy entryway into your system, often through unpatched vulnerabilities that they can exploit to gain privileged access and begin spreading malware across it all or disrupting services. Once in, attackers can gain a foothold within your network that allows them to exploit and take over as they steal data or disrupt services.

Good news is that organizations can detect and remediate exposures quickly using threat intelligence and continuous monitoring with Edgescan EASM. Security leaders can use Edgescan EASM to get an overview, prioritize what matters and address exposures before they turn into breaches or ransomware attacks. It is the most effective way of stopping serious cyber threats from succeeding.

How to define the attack surface area?

Deliberately defining an organization’s attack surface area is essential to effective cybersecurity. The more expansive its attack surface is, the easier it is for attackers to gain entry and steal data or disrupt systems and services.

An effective approach for attacking and securing the attack surface entails continuous discovery, vulnerability assessment, testing, and remediation – with consideration given to all digital assets including third-party and supply chain assets owned by an enterprise.

Digital threats include attacks that exploit vulnerabilities in network infrastructure, applications and Web servers; or take advantage of unintended external system access points (for instance default operating system settings, unpatched vulnerabilities, unused web ports, APIs and exposed databases). Physical attack surfaces range from improperly disposed hardware such as endpoint devices that have not been secured properly discarded items stored passwords stored on paper to any form of physical access that allows unauthorized data access.

Equifax was breached through an unpatched vulnerability on a public-facing web server that exposed usernames and passwords in cleartext, giving attackers leverage to lateral move across its network, eventually exfiltrating critical data.

Challenges around External Attack Surface Mapping

Attackers conduct comprehensive assessments and penetration tests of an organization’s IT ecosystem on an almost constant basis, searching for vulnerabilities to exploit in its network configuration, protocols and services in order to gain entry, gain access, steal data or disrupt operations.

Modern organizations’ digital footprint is vast and complex, making it difficult to uncover all internet-facing assets such as websites, applications and cloud infrastructure. Furthermore, this landscape changes continuously due to assets being created, modified or retired – this makes modeling, detecting and mitigating weaknesses on a timely basis challenging.

Digital attacks often exploit programming flaws, default system settings and open application programming interfaces in web apps and servers. Attackers may also utilize physical attacks surfaces containing login credentials or sensitive data as well as unpatched software that could allow unauthorized entry.

Effective attack surface management involves the ongoing discovery, monitoring and mitigation of vulnerabilities at remote entry points. For faster remediation workflows, security teams should provide detailed yet actionable evidence along with specific guidance to IT operations to quickly eliminate risk.

Risks Associated With Limited Attack Surface

Attackers are constantly looking for any opportunity to gain entry to an organization’s systems, data or services illegally. Therefore it’s vital for businesses to identify, monitor and evaluate their external attack surface regularly.

Internet-facing assets, such as websites, cloud infrastructure, and IOT devices are the first target for attackers looking to gain entry. Vulnerabilities within these assets often act as the gateway into accessing an organization’s internal networks or vital data.

Vulnerabilities can come from various sources. A common example includes misconfiguration of assets, network architecture flaws and data exposures. Furthermore, third-party software, hardware or integrations introduce additional risks into an attack surface.

Multiple discovery tools may create visibility gaps due to their massive amounts of data and alerts being difficult for security teams to manage and prioritize. Furthermore, using multiple departments within an organization makes sharing digital risk assessment results difficult; leading to siloed teams with limited transparency that reduce the efficacy of all security processes.

How Does External Attack Surface Management helps?

As businesses expand, their online assets increase as do potential entry points for attackers. As their number increases, so too do vulnerabilities – making robust cybersecurity measures essential.

Assessing these assets for vulnerabilities can be an arduous task for organizations with limited resources, necessitating automated discovery and cataloguing as well as continuous monitoring and threat intelligence gathering. A holistic approach requires automated discovery and cataloging as well as continuous monitoring and intelligence collection.

Prioritize risks based on their potential impacts. For instance, vulnerabilities found in public repositories like GitHub could allow threat actors to steal data or disrupt services, so prioritization allows teams to focus on the most urgent vulnerabilities first and lower compliance costs. A holistic approach to attack surface management also identifies misconfigurations, exposed credentials and third-party software as potential exploitable risks; sharing this data with key vendors expedites remediation processes.

Identify Unknown Risks and Exposures in Real time

As new services, devices, and applications join an organization’s network, the attack surface of their organization grows steadily – potentially increasing risk through vulnerabilities, misconfiguration, or data exposures that go undetected.

To address this challenge, organizations require an attack surface management program that continuously discovers, tests, and prioritizes all external-facing assets of their organization; including internet-facing servers, ports, domains, SSL certificates, IoT devices and third-party cloud services. Furthermore, such a solution must also understand business context of discovered assets or vulnerabilities so they can be quickly and accurately prioritized for remediation.

Recent events like the MoveIT transfer file data breach highlighted how third-party services can open your internal networks to attackers. A comprehensive EASM program would enable security teams to gain visibility into this exposure and work with vendors for expedient remediation efforts. An ASM tool such as Edgescan EASM could help streamline operations by automatically discovering, testing and prioritizing unknown threats across services, devices and platforms so your resources can focus on remediating known vulnerabilities and threats instead.

Streamline Operations

Due to digital assets and cloud services’ continued expansion, modern attack surfaces are increasingly complex and dynamic. When combined with mergers and acquisitions, remote work models, and third-party suppliers’ proliferation, risks become virtually impossible to manage without external assistance.

Top EASM solutions allow teams to overcome this informational imbalance by automating discovery and detection of vulnerabilities, providing detailed business context, and offering prioritized action items. In addition, top solutions allow security teams to communicate their risk posture to their critical stakeholders effectively.

Your organization requires a comprehensive view of its external attack surface in order to make informed risk response decisions. A top-tier EASM solution gives this visibility by continuously re-assessing and tracking changes across internet-facing assets of your organization, while simultaneously detecting anomalies or suspicious behaviors across them all – providing your security team with valuable intelligence that enables smarter security decisions which help prevent data breaches while mitigating cyberattacks.

Attackers are constantly looking for the least resistant route into your organization. They’ll comb through all aspects of digital footprint to locate misconfigurations, vulnerabilities and exposures in search of an entryway into their target.

An effective external attack surface management solution should inventory, monitor, and manage internet-facing assets and third-party risks on a comprehensive level, including prioritizing potential entry points for attackers.

Components Of External Attack Surface Management

An organization’s digital attack surface refers to everything exposed to the internet: servers, domains, cloud services, IoT devices and operating systems as well as misconfigurations and shadow IT assets that could expose their company at any given time and are often beyond the reach of existing firewalls and endpoint protection solutions.

An effective cybersecurity approach requires keeping an attacker’s attack surface small to protect sensitive information and prevent data breaches. EASM helps organizations reduce this external attack surface by identifying their most vulnerable assets and applying security controls to them.

Security teams need visibility across their entire IT ecosystem in order to effectively manage the attack surface, which is why EASM should include continuous discovery, asset classification and risk-based prioritization capabilities. This enables CISOs to quickly identify unknown risks that need remediation before becoming cyber threats; also helping strengthen their cybersecurity posture, maintain customer trust and comply with industry regulations.

1. Autonomous Exposed Assets

Digital footprint of an organization encompasses all assets publicly accessible on the internet, such as websites, servers, domains, SSL certificates and cloud infrastructure. Cybercriminals use this attack surface to gain entry into internal systems, steal data or disrupt services.

As organizations engage in digital transformation projects and utilize remote workforces, these risks become even greater.

Autonomously exposed assets must be identified and classified to effectively manage the attack surface. This involves mapping assets to business units or subsidiaries for easier owner identification and integration with existing SOC tools for faster vulnerability remediation. Once discovered assets and vulnerabilities have been prioritized according to threats and impacts areas; security teams must then focus their efforts where they will have maximum effect while also monitoring new assets that emerge over time.

2. Business Context Insight

Modern businesses maintain an expanding digital footprint that includes websites, APIs, IP addresses, domains, SSL certificates and cloud services that may be managed by different teams (IT security teams or business units for example). Accurate identification and inventorying is key in understanding which assets could be vulnerable to cyberattacks.

Effective attack surface management solutions must provide visibility into the context of vulnerabilities, so as to prioritize remediation efforts for specific business-critical systems. In addition, security teams should collaborate with other departments and business unit leaders in order to gain an overall view of the environment from both user and attacker perspectives.

Organizations need to adapt their defenses against evolving threats by revisiting how they approach their attack surface. To do this, organizations should adopt an approach which automates discovery and provides a continuous view of all digital and “smart” technologies–on-prem, cloud, through subsidiaries/third-party vendors/digital supply chains or even remote workers’ devices.

3. Automatic Asset Classification

With remote working and the cloud becoming the norm, sensitive and important data often exist outside the traditional asset and network boundaries of organizations – increasing their vulnerability and risk of cyber incidents.

An effective asset recording and evaluation system must exist in order to identify and assess assets on an ongoing and automated basis, including an automated view that combines ownership, business criticality, risk context and more effective security teams’ work.

Security teams need an attack surface management solution capable of quickly finding and closing vulnerabilities faster than attackers can exploit them, including shadow IT, orphaned applications, outdated systems, vulnerable software applications, expired SSL certificates, DNS records and third-party integrations – among other types. With this information they can prioritize remediate risks to improve security posture; this requires automated classification against commercial, open source or proprietary threat intelligence feeds as well as continuous asset discovery with continuous classification evaluation against these feeds.

4. Continuous External Surface Monitoring

As threats evolve rapidly, it’s critical for organizations to keep pace with them by continuously monitoring attack surfaces. Doing so provides visibility and detail required to protect critical assets against misconfigurations, weaknesses and vulnerabilities that attackers could exploit to launch data breaches and cyberattacks against critical assets.

Effectively mapping the digital attack surface requires using automated discovery techniques and highly accurate testing methods, with prioritization capabilities that allow teams to focus on high risk assets first and address crucial issues immediately.

As companies strive to secure on-premises and cloud infrastructure, it’s also essential that they consider the broadened attack surface – including remote workers, third-party software, IoT devices, SaaS platforms and other services – as possible entryways that attackers could exploit to gain entry. With so many external assets being acquired by organizations each day, companies could easily overlook some potential entry points that allow attackers to gain entry.


An organization’s attack surface includes all digital assets that connect to the internet, either directly or via third party services such as IoT devices and cloud services. These can be exposed through misconfigurations, unpatched vulnerabilities or by simply being openly available; with remote work and IoT increasing numbers of these assets leaving behind their firewall.

An EASM strategy must include comprehensive monitoring of an organization’s external attack surface in order to successfully reduce risks from attacks. This requires using automated discovery techniques, business context insight, prioritization tools and rapid remediation workflows in combination.

Prioritizing risks within an attack surface allows security teams to quickly address them with minimal impact to business. Furthermore, prioritization ensures that the appropriate team is responsible for each identified risk; reducing false positives and improving productivity. Finally, continuous monitoring ensures the organization stays aware of new threats quickly enough to respond appropriately.

Sam is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.