EASM vs vulnerability scanning: What’s the difference?

As your organization grapples with an ever-expanding digital footprint — driven by the proliferation of cloud services, remote work, and Internet of Things (IoT) devices — your IT team faces an important decision. How do you effectively identify and mitigate risks across your entire digital ecosystem, protecting all of your assets – even the ones you might not know about? 

Two popular approaches, external attack surface management (EASM) and vulnerability management (VM), offer different but complementary solutions. In this post, we'll explore the distinctions between these tools, identifying their strengths and weaknesses. We'll also discuss why investing in both tools may be the key to comprehensive cybersecurity.

Vulnerability management: What it is and how it works

Vulnerability management describes the systematic process of identifying, evaluating, treating, and reporting security vulnerabilities within an organization's systems and software, primarily focusing on software-based vulnerabilities. 

The process works by performing an asset inventory, starting with a predefined list of IP addresses and systems and conducting regular scans to detect known vulnerabilities. IT staffers typically schedule these scans weekly, monthly, or quarterly, depending on the organization's needs and risk profile. 

After scanning, vulnerability management assesses each vulnerability's severity, often using the Common Vulnerability Scoring System (CVSS) to measure. Post assessment, vulnerability management tools prioritize issues, ranking them for remediation based on their potential impact. Finally, IT staffers remediate the issues, applying patches and implementing other mitigations before documenting results in a report for compliance and tracking purposes. 

Strengths of vulnerability management

Vulnerability management boasts many strengths, including:

• Deep analysis: VM provides detailed insights into specific vulnerabilities within known systems.
   
• Compliance: Vulnerability management helps organizations meet regulatory requirements for regular security assessments.
   
• Quantifiable results: VM offers clear metrics on how your organization has reduced vulnerability over time.

Limitations of vulnerability management

While it has numerous strengths, vulnerability management also has its limitations, including:

• Limited scope: VM only scans pre-defined assets, potentially missing unknown or shadow IT resources.
   
• Point-in-time view: Vulnerability management tools provide a snapshot rather than continuous monitoring.
   
• Requires expertise: Properly configuring VM scans and interpreting results often demands specialized knowledge.

External attack surface management: What it is and how it works

EASM is a comprehensive process of discovering, analyzing, and continuously monitoring an organization's external-facing digital footprint. It has a broader scope than vulnerability management, focusing on the interconnectivity of assets and potential attack vectors across the IT ecosystem. 

The process begins with asset discovery, automatically identifying all internet-facing assets associated with an organization, including unknown and shadow IT resources. This discovery phase requires minimal input, often starting with just a company name or primary domain names.

EASM performs continuous, automated scans that typically don't require specific scheduling or approval. These scans are iterative, with each discovery potentially triggering additional specialized scans. After discovery, EASM conducts ongoing risk assessments, evaluating potential vulnerabilities and misconfigurations across all assets. It also incorporates third-party risk analysis, assessing risks from connected vendors and partners, and integrates threat intelligence data on emerging threats and attacker tactics.

Post-assessment, EASM tools prioritize issues, highlighting the most critical areas for immediate attention. The tools continuously update results, represented per asset type and risk group. This allows you to focus on identifying vulnerabilities while creating a complete asset inventory and flagging IT assets for potential decommissioning or as shadow IT. 

Strengths of EASM

The EASM approach has multiple strengths, including:

• Comprehensive coverage: EASM lets you discover unknown assets and shadow IT.
   
• Attacker's perspective: The EASM approach views your organization from the same perspective an attacker would see.
   
• Continuous visibility: EASM tools provide real-time insights into the changing attack surface.
   
• Third-party risk management: EASM tools extend your visibility to the supply chain.

Limitations of EASM

Although it has numerous strengths, EASM has a few limitations, too, including:

• Broader, less deep: EASM may not provide the same level of detail as VM for known vulnerabilities.
   
• Potential for false positives: The wide net cast by EASM can sometimes flag benign issues.
   
• Requires context: Effective EASM use often requires an in-depth understanding of the broader IT landscape.

Why EASM is worth the investment

While there is some overlap between EASM and vulnerability management, the reality is that EASM offers several unique benefits that make it a valuable addition to any cybersecurity strategy:

• Holistic view: EASM provides a comprehensive picture of your organization's digital footprint, including assets that traditional VM tools might miss.
   
• Proactive approach: By continuously monitoring for new assets and changes, EASM helps your organization stay ahead of potential threats before attackers can exploit them.
   
• Shadow IT discovery: EASM excels at uncovering unknown or unauthorized assets that could pose significant risks.
   
• Dependency insights: By assessing dependencies with third parties like webhosters or in the website code, EASM helps protect against increasingly common supply chain attacks.
   
• Efficiency gains: EASM frees up IT resources to focus on addressing the most critical issues by automating the discovery and monitoring process.
   
• Strategic alignment: EASM's broad view aligns well with overall business risk management, helping you to prioritize security investments.
   
• Complementary to VM: Rather than replacing VM, EASM enhances its effectiveness by ensuring all assets are accounted for and monitored.

A holistic approach

While vulnerability management remains essential for deep analysis of known systems, EASM offers a broader, more dynamic view of an organization's cybersecurity posture. By investing in both EASM and VM, your organization can create a holistic approach that combines depth and breadth. Today, the question isn't whether to choose between EASM and vulnerability management but how to integrate both effectively. By leveraging the strengths of each approach, your organization can build a more resilient defense against whatever threats come your way.

Interested to learn how EASM could fit in with your organization? Book a free attack surface analysis with an Outpost24 expert today.