What is External Attack Surface Management (EASM)?

Your digital perimeter might seem secure, but without full visibility into your external assets, you could be leaving the door open for cybercriminals. External Attack Surface Management (EASM) offers an ongoing, proactive solution, scanning your digital environment to identify and mitigate vulnerabilities in real-time. This isn’t just a one-time assessment but a robust defence that adapts as your attack surface evolves.

Why is External Attack Surface Management important?

Attackers have countless ways to target your systems. Without understanding the probability and impact of these threats, you may end up focusing on the wrong issues. This is where EASM comes in—it helps you identify, prioritise, and address the most critical risks.

EASM dynamically tracks public-facing assets and leverages real-time threat intelligence, helping your business to anticipate and respond to potential threats effectively as your digital footprint grows.

A key advantage of EASM over traditional penetration testing is its ability to uncover blind spots. It doesn’t just focus on systems you already know about—it actively searches for assets and vulnerabilities you may not be aware of, preventing attackers from exploiting overlooked entry points.

According to a 2023 report by the Australian Cyber Security Centre (ACSC), cybercrime reports surged by 13% in just one year, with over 76,000 incidents​. Many of these attacks targeted external vulnerabilities such as misconfigured systems or exposed interfaces.

Key components of an External Attack Surface Management

1. Asset discovery and contextualisation

EASM begins by identifying all external-facing assets, including unknown systems. It goes beyond discovery, providing critical context on asset importance and sensitivity to prioritise security efforts.

EASM identifies compromised credentials circulating on the dark web. By proactively addressing these threats, you can prevent unauthorised access before an attack occurs.

3. Exposure identification

EASM identifies compromised credentials circulating on the dark web. By proactively addressing these threats, you can prevent unauthorised access before an attack occurs.

4. Vulnerability assessment and prioritisation

EASM focuses on real, exploitable risks—such as exposed RDP ports and misconfigurations—prioritising vulnerabilities based on their attractiveness to attackers. This ensures your resources target the most critical threats.

How EASM fits into a comprehensive cyber security strategy

EASM works best when integrated into a broader cyber security strategy. While it focuses on external threats, it complements internal security assessments, penetration testing, and ongoing monitoring. Together, these approaches form a layered defence, ensuring both external and internal risks are managed.

For example, internal assessments focus on your organisation’s internal infrastructure and employee behaviour. Penetration testing simulates attacks to find vulnerabilities, but EASM continuously monitors the external perimeter, catching new threats as they arise. Together, these strategies provide a robust security posture.

EASM vs. Penetration Testing: Complementary but distinct

While both EASM and penetration testing are essential, they serve different purposes. Below is a detailed comparison of how each approach works and what they’re best suited for:

EASM provides continuous monitoring for evolving infrastructures, making it ideal for proactive threat detection and compliance. Penetration testing, meanwhile, is better suited for periodic, in-depth assessments of internal and external systems. Both are critical but serve different purposes in securing your organisation.

Benefits of implementing EASM for businesses

1. 1. Proactive threat identification

   EASM uncovers vulnerabilities—like exposed management interfaces and compromised credentials—before they can be exploited. This proactive approach leverages external threat intelligence to stay ahead of attackers by mitigating risks early.

3. 2. Cost-effective risk mitigation
   Identifying vulnerabilities before they are exploited is more cost-effective than responding to an attack. EASM directs your resources towards significant risks, avoiding wasted efforts on minor issues.
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5. 3. Enhanced compliance and governance

   EASM’s continuous monitoring ensures alignment with regulatory standards by regularly tracking external assets and reducing risks associated with public exposure, making audit preparation simpler and improving overall governance.

6. 4. Focus on real, exploitable risks
7. EASM prioritises high-impact vulnerabilities such as exposed RDP ports and credential leaks. Automated testing ensures you focus on the most critical threats, reducing the risk of breaches.

Choosing the right provider for your External Attack Surface Management

When selecting a cyber security provider for EASM, there are several key factors to consider to ensure the provider can deliver effective, comprehensive results:

• Experience: Select a provider with proven expertise in EASM and an understanding of your unique digital infrastructure.
• Tools & technologies: Ensure they use a mix of cutting-edge automated tools and manual methods for thorough assessments.
• Ongoing monitoring: Continuous monitoring is crucial to detect new vulnerabilities as they arise.
• Tailored solutions: Providers should offer solutions that align with your specific needs.
• Best practices: Choose those who follow industry frameworks like MITRE ATT&CK, which maps real-world tactics used by attackers. This ensures that your external surface attack assessment focuses on detecting the most relevant threats based on actual adversary behaviour, enhancing your ability to prioritise and mitigate high-risk vulnerabilities.
• Comprehensive analysis: They should uncover both known and unknown risks, including dark web credential checks.
• Actionable reporting: Reports should prioritise real threats and provide clear remediation steps.

At The Missing Link, we offer comprehensive External Attack Surface Assessments (EASM) that align with best practices and frameworks like MITRE ATT&CK. Our tailored solutions address your specific needs by combining cutting-edge automated tools and manual expertise. With continuous monitoring, we detect emerging vulnerabilities, uncover both known and unknown risks, and provide actionable reports that prioritise real threats.

Steps involved in an External Attack Surface Assessment

To fully secure your external assets, an EASA follows a systematic approach, addressing every aspect of your digital infrastructure. The process involves four key steps to ensure that vulnerabilities are identified and resolved efficiently. Here's a breakdown of these steps:

1. 1. Asset discovery: Identify all external-facing assets, including websites, servers, applications, and cloud instances.
2. 2. Vulnerability scanning: Use both automated tools and manual techniques to scan these assets for vulnerabilities.
3. 3. Risk prioritisation: Rank vulnerabilities by threat level and potential impact on your organisation.
4. 4. Remediation planning: Provide actionable insights to resolve the identified vulnerabilities, ensuring your security is strengthened.

This assessment is an essential step toward securing your external-facing assets, reducing exposure to cyber threats, and preparing for ongoing External Attack Surface Management.

Want to try it out?

If you're ready to enhance your security with continuous monitoring, an External Attack Surface Assessment is the ideal first step. It provides an insightful baseline, setting the stage for ongoing EASM to secure your organisation’s digital perimeter effectively.

Contact us today for a tailored EAS Assessment and take the first step towards a proactive cyber security strategy.