What is EASM

External Attack Surface Management (EASM) is a process of monitoring and securing all the external assets exposed to the internet. These assets can include websites, servers, IoT devices, and APIs.EASM helps organizations to map their attack surface i.e. mapping the potential entry points attacker could attack or exploit. This process helps security teams to understand and be aware of all the entry points, even those that might be overlooked during security checks.

Importance of EASM

Organizations today use cloud services, hybrid work culture, and third-party vendors, which tremendously increase the attack surface and external assets. Traditional security measures are always focused on internal assets, leaving external assets prone to cyberattacks.

Here are some of the reasons why EASM is important

  • Zombie APIs and Shadow IT: Organizations often overlook their external assets. These assets could be APIs, forgotten cloud resources, or third-party applications. EASM helps organizations to identify these assets and address the vulnerabilities before being exploited by threat actors.
  • Rapid Attack Surface Expansion: With the increase in cloud services and hybrid work culture, the attack surface of an organization is increasing rapidly. Managing this attack surface without centralized EASM is difficult.
  • Compliance and Regulatory Requirements: Many organizations are subject to regulatory requirements, such as GDPR, PCI DSS, DORA, and HIPAA, which mandate the protection of data internally and externally.EASM ensures all external assets comply with security standards to avoid heavy fines and penalties.
  • Data Breaches: Attackers often use external assets as entry points to gain access. By monitoring external assets such as APIs, misconfigured servers, and others, data breaches can be prevented.

Related Reading: The Role of EASM in Third-Party Risk Management

How to implement EASM in your organization

Step 1:Identify all the external-facing assets

The first step in implementing EASM in your organization is to identify all the external-facing assets(internet-facing). This includes

  • Websites
  • Web Applications
  • APIs
  • Cloud Services
  • Internet of Things (IoT) devices etc

Many organizations do not have the proper knowledge of their external assets, especially if they rely on third-party services, cloud services, etc.

Step 2:Mapping Attack Surface

Once all your external assets are discovered, you need to map the attack surface. This involves understanding how each asset interacts with others and the potential vulnerabilities exposed online. Mapping can be done manually, but automated EASM reduces the time and simplifies the process. These tools help

  • Identify exposed services
  • Detect misconfiguration 
  • Mapping attack paths

Step 3:Prioritize Assets Based on Risk

Once the external assets are identified and mapped, the next task is to prioritize the assets based on their importance to your organization’s operation and the risks they pose. Not all assets are critical may be highly critical(databases), while others may not.

If possible, integrate threat intelligence to get better risk prioritization and profiling. Moreover, Prioritizing assets helps you to secure the critical attack vector first.

Step 4:Identify Vulnerabilities

After prioritizing your external assets, the next step is to carry out a thorough vulnerability assessment. This involves scanning for common vulnerabilities and exposures (CVEs), misconfigurations, weak access control, etc.

Step 5:Implement Fixes

Once vulnerabilities are identified, it’s crucial to implement mitigations. Some of the common security measures include:

  • Patching: Updating software, firmware, and applications to ensure that reported and known vulnerabilities are patched.
  • Access Control: Limit access to systems based on the least privilege model. If possible, implement multi-factor authentication (MFA) and other security measures.
  • Segmentation: Segment your network to prevent the lateral movement of threat actors in the network or systems during a cyberattack.
  • Web Application Firewalls(WAF): Deploy WAF to protect websites and web applications from SQL injection or cross-site scripting(XSS).

Step 6:Regularly Update your policies

Always review and update your security policies of External Attack Surface Management (EASM) based on your organization’s risk profile. Updating security policies ensures your organization keeps pace with modern threats and attack techniques.

Step 7:Train Your Employees

Human is the weakest link in the IT infrastructure. So, it is important to train your employees while implementing EASM. Security awareness training should be conducted regularly to ensure that staff members follow best practices and to 

✅Recognize phishing attempts

✅Handling sensitive data properly

✅Reporting suspicious activity

Conclusion

Implementing External Attack Surface Management (EASM) is crucial for your organization to reduce digital risk. With continuous monitoring and real-time threat intelligence, you ensure that all assets—whether owned or third-party—are secured, minimizing the potential impact of external vulnerabilities. By identifying, mapping, prioritizing, and securing external assets, you can reduce the likelihood of data breaches, cyberattacks, or ransomware attacks.