External Attack Surface Management: 5 Key Capabilities

What Is External Attack Surface Management (EASM)

External attack surface management (EASM) focuses on managing and securing an organization's digital assets exposed to external threats. These assets include websites, IPs, cloud services, and any digital entry point accessible from the internet. The goal of EASM is to map, monitor, and reduce these potential attack points to mitigate risks.

EASM involves continuously discovering, classifying, and analyzing these external digital assets. By doing so, it identifies vulnerabilities that attackers might exploit. This proactive approach allows organizations to understand their security stance and make informed decisions to protect against cyber threats. EASM is integral to cybersecurity strategies due to the increasing complexity and distributed nature of modern IT environments.

Importance of External Attack Surface Management

The attack surface of most organizations is expanding due to cloud adoption, remote work, and digital transformation. EASM helps organizations map this growing perimeter and safeguard against potential threats. Without EASM, businesses run the risk of unnoticed vulnerabilities being exploited by malicious actors.

Externally exposed assets are often targeted by attackers. EASM provides visibility into these assets, allowing organizations to assess risks and prioritize remediation. This process ensures resources are focused on the most critical vulnerabilities, enhancing overall security posture. As cyber threats evolve, the importance of EASM continues to rise, making it a core component of modern cybersecurity efforts.

Understanding External Attack Surfaces

An external attack surface comprises all the points through which an external entity can interact with an organization’s digital assets. This includes websites, APIs, cloud platforms, and visible IP addresses.

Internal vs. External Attack Surfaces

Internal attack surfaces refer to vulnerabilities and potential attack vectors within an organization's network, such as databases or internal applications. External attack surfaces, however, are exposed to the internet, like web services and externally accessible APIs.

While internal attacks often come from insiders or infiltrations, external attacks are more commonly perpetrated by external hackers exploiting outward-facing vulnerabilities. Managing both is essential, but external surfaces often require more immediate attention due to their accessibility to outside threats. Hence, EASM prioritizes identifying and securing these external vulnerabilities.

Common External Attack Vectors

External attack vectors commonly include techniques such as phishing, exploiting software vulnerabilities, and DDoS attacks. Hackers often target external web-facing assets or services, seeking to gain unauthorized access or disrupt operations.

Vulnerable web applications, outdated server software, and weak network configurations are typical vectors. Organizations must perform rigorous testing and monitoring to detect and eliminate such weaknesses. Understanding these vectors allows businesses to align their defense strategies appropriately to prevent successful exploitation by external actors.

How EASM Works

The EASM process includes the following primary stages:

Discovery of External Assets

The initial step in EASM is identifying all external-facing assets. This process requires automated scanning tools to detect domains, IPs, and cloud instances connected to the organization's network. Regular scanning is vital given the dynamic nature of digital environments.

Asset discovery allows businesses to gain complete visibility into their external attack surface. It ensures no asset is unintentionally exposed, providing an overview of what needs monitoring. Accurate asset inventory helps in better risk mitigation and reinforces the organization's security measures by pinpointing assets subject to external threats.

Continuous Monitoring and Assessment

Continuous monitoring involves real-time surveillance of digital assets for vulnerabilities and malicious activities. This approach allows organizations to detect and respond to breaches swiftly, minimizing potential damage.

By consistently assessing asset health and security, organizations can identify and close security gaps promptly. Continuous monitoring involves regularly updating and patching software, performing penetration testing, and utilizing threat intelligence to stay ahead of emerging threats. This vigilance ensures defense mechanisms against evolving cyber threats, maintaining the security and integrity of digital assets.

Risk Prioritization and Remediation

After identifying vulnerabilities, companies must prioritize risks based on potential impact. This involves assessing the likelihood of exploitation and potential damage if exploited. Risk prioritization ensures critical vulnerabilities are addressed first, optimizing resources and efforts.

Remediation follows, involving activities like patching vulnerabilities, disabling unnecessary services, or implementing better security controls. Effective remediation reduces the attack surface, diminishing opportunities for potential attackers.

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Mike Belton - Head of Service Delivery

With 25+ years in infosec, Michael excels in security, teaching, and leadership, with roles at Optiv, Rapid7, Pentera, and Madison College.

Utilize attack surface reduction (ASR) techniques alongside EASM

Beyond merely mapping assets, employ ASR strategies such as disabling or isolating non-essential services and enforcing the principle of least privilege. This complements EASM by shrinking the exposed attack surface, minimizing potential vectors before they become exploitable.

Monitor domain-based attack vectors such as typosquatting

Attackers often set up fake domains mimicking legitimate ones (e.g., typosquatting). Implement a process to continuously scan for suspicious domains similar to your organization’s, which could be used in phishing or impersonation attacks.

Establish robust API governance

APIs are increasingly targeted by attackers, yet often overlooked in EASM. Ensure that all external APIs are properly documented, authenticated, and monitored. Implement API gateways and enforce strong API authentication policies to prevent unauthorized access.

Establish a robust digital footprint mapping process

Go beyond asset discovery tools and map out your digital footprint regularly by including mentions of your brand in public forums, code repositories, or black markets. This provides valuable intelligence on whether your external assets or data have already been compromised.

Account for ephemeral cloud instances in asset management

Cloud environments frequently spin up and tear down instances, which can be missed during asset discovery scans. Ensure your EASM process includes robust tagging and monitoring mechanisms for ephemeral cloud assets to avoid blind spots in your attack surface.

EASM vs. CAASM

External Attack Surface Management (EASM) and Cyber Asset Attack Surface Management (CAASM) are both crucial to a robust cybersecurity strategy, but they focus on different aspects of an organization's security landscape.

EASM is primarily concerned with managing and securing all external-facing digital assets. These assets are accessible from the internet and include domains, IP addresses, APIs, and cloud services. EASM focuses on continuously discovering, monitoring, and mitigating risks associated with these outward-facing assets, providing organizations with visibility into how attackers might target them from the outside.

CAASM focuses on providing comprehensive visibility into internal and external cyber assets within an organization. This includes both managed and unmanaged assets, such as endpoints, devices, applications, and cloud infrastructure. Unlike EASM, CAASM integrates data from various internal tools like vulnerability scanners, endpoint detection, and configuration management databases (CMDBs) to offer a holistic view of the organization's entire attack surface. This allows organizations to understand both external risks and internal weaknesses in tandem.

While EASM is specialized in managing threats from external actors, CAASM provides a more detailed and unified inventory of all cyber assets, which helps in both internal and external security risk management.

Key Capabilities of EASM Solutions

1. Asset Discovery

Asset discovery involves identifying all possible external connections, such as websites, APIs, and cloud instances. Utilizing automated tools, organizations can rapidly detect changes and newly exposed assets, ensuring nothing is overlooked.

A thorough discovery process lays the groundwork for continuous monitoring and risk management. It encompasses all visible and hidden assets, providing a full inventory critical for strategic planning. By understanding the extent of the attack surface, companies can better direct their security strategies to protect these at-risk assets.

2. Real-Time Monitoring

Real-time monitoring is essential for maintaining ongoing visibility into asset security. It allows organizations to detect anomalies and activities indicating potential threats, facilitating swift responses.

This capability helps in mitigating risks before they arise by providing timely alerts and insights into ongoing threats or policy violations. Real-time monitoring ensures that security efforts are not static, adapting swiftly to changes in the threat landscape. This dynamic approach to monitoring is vital for responsive cybersecurity practices.

3. Integration with Security Tools

Integration with existing security tools ensures that EASM functions within an organization's broader security strategy. This includes compatibility with SIEMs, firewalls, and endpoint protection platforms.

Such integration leverages existing infrastructure, enhancing threat detection and response capabilities without requiring significant changes or redundancies. It facilitates better communication between systems, ensuring coordinated responses to threats. Integrated EASM solutions offer streamlined operations and improved security posture by working with established security frameworks.

4. Scalability and Coverage

Scalability ensures EASM solutions can adapt to growing digital environments. As organizations expand, so do their attack surfaces; a scalable solution can accommodate increasing assets without compromising performance.

Coverage refers to the scope within which an EASM solution operates, ensuring all potential entry points are monitored and secured. Effective EASM tools address both concerns, offering protection across expansive or evolving networks. Scalability and coverage are crucial for maintaining security as organizations adapt to new technologies and infrastructures.

5. Actionable Reporting and Analytics

Actionable reporting transforms collected data into insights, enabling organizations to understand their risk landscape clearly. Analytics provide detailed evaluations of security posture, identifying patterns and trends.

These reports help in strategizing remediation efforts, assessing the effectiveness of security measures, and fulfilling compliance requirements. By delivering clear, concise, and actionable insights, EASM enables informed decision-making, aiding in continuous improvement and proactive security management.

Challenges in External Attack Surface Management

Shadow IT and Unknown Assets

Shadow IT and unknown assets refer to unauthorized or overlooked digital resources that bypass security oversight, creating vulnerabilities. Employees often use unvetted applications to enhance productivity, inadvertently expanding the attack surface.

Identifying and managing these assets is challenging but essential. Organizations need discovery tools and clear policies to mitigate the risks posed by shadow IT. Regular audits and staff training can also play a role in minimizing unauthorized use of technology, safeguarding against potential security breaches.

Rapidly Changing Environments

Rapid changes in digital environments, driven by agile development and upgrades, increase vulnerability risks. These changes often outpace traditional security measures, making it difficult for organizations to maintain a secure exterior.

Adaptive EASM practices help manage these changes by employing continuous monitoring and flexible security strategies. Maintaining a balance between rapid innovation and stringent security is key. Organizations must ensure that evolving environments do not compromise security, implementing real-time checks and updates to protect against emerging threats.

Resource Constraints

Resource constraints, including limited budgets and staffing, challenge EASM implementation. Maintaining effective security measures requires time, expertise, and financial investment, all of which can be scarce.

Organizations need to prioritize and optimize available resources to manage external attack surfaces. Cost-effective solutions, automation, and collaboration with third-party providers can alleviate some of these constraints. Strategic resource allocation ensures that critical vulnerabilities are addressed, enhancing the overall security framework.

Best Practices for Implementing EASM

Regularly Update Asset Inventories

Regularly updating asset inventories is crucial for maintaining visibility over the external attack surface. Digital environments are dynamic, with assets frequently added or modified, necessitating up-to-date records.

Frequent audits and automated tools can help organizations keep inventory accurate, aiding in effective management of external threats. This practice ensures that security measures are applied consistently across all assets, reducing the chance of vulnerabilities going unnoticed and exploited.

Prioritize Remediation Efforts

Prioritizing remediation efforts ensures that vulnerabilities posing the greatest risk are addressed first. This involves evaluating potential impact and likelihood of exploitation, allocating resources to high-priority issues.

Effective prioritization helps organizations manage limited resources efficiently, focusing on the most severe threats. Structured remediation plans minimize exposure to potential attacks, strengthening the overall security stance and ensuring timely vulnerability resolution.

Integrate EASM with Existing Workflows

Integrating EASM with existing workflows enhances operational efficiency by streamlining processes and reducing the administrative burden. This integration ensures that security measures become part of routine operations.

By embedding EASM into conventional workflows, organizations can enhance their threat detection and response capabilities. It promotes a proactive approach to managing external risks, leveraging existing tools and processes to maintain continuous protection against threats.

Enable Cross-Functional Collaboration

Cross-functional collaboration involves integrating insights from IT, security, and business units to enhance EASM strategies. Sharing information and expertise across departments strengthens threat detection and response.

Collaborative efforts ensure understanding of organizational assets and vulnerabilities, facilitating more effective security measures. This approach enhances overall cybersecurity posture, mitigating risks associated with external attack surfaces by leveraging collective insights and resources.

Utilize Automation and AI

Automation and AI technologies streamline EASM processes, offering capabilities like automated threat detection, analysis, and response. These technologies enhance efficiency and accuracy in managing external attack surfaces.

By utilizing these technologies, organizations can tackle complex security challenges and minimize human error. Automation supports real-time monitoring and rapid response, ensuring consistent protection without overburdening resources, thereby enhancing overall security frameworks.

Advanced Strategies for Managing External Attack Surfaces

Incorporating Threat Intelligence Data

Incorporating threat intelligence data into EASM strategies allows organizations to anticipate and counteract potential threats more effectively. Threat intelligence provides insights into attacker methodologies and targets.

By leveraging this data, companies can adapt their defenses to address specific vulnerabilities, enhancing prevention and detection capabilities. This intelligence-driven approach ensures that security measures remain proactive, staying ahead of emerging threats and protecting exposed assets from potential attacks.

Managing Third-Party and Supply Chain Risks

Managing third-party and supply chain risks is critical given the increased vulnerability these relationships introduce. Organizations must evaluate and monitor their partners' security practices to ensure risks are mitigated.

Strengthening third-party management involves rigorous assessments, continuous monitoring, and enforcing security standards. It ensures that external parties do not present exploitable vulnerabilities, reducing the potential attack surface and securing the digital supply chain.

Aligning EASM with Compliance Standards

Aligning EASM with compliance standards ensures organizations meet regulatory requirements while maintaining a secure digital presence. Compliance helps in establishing baseline security protocols, reducing the threat landscape.

Adhering to these standards involves regular reviews, audits, and updates to maintain consistency in security practices. Compliance alignment strengthens overall security posture, ensuring that organizations protect their attack surfaces while meeting industry and legal obligations.

Attack Surface Management with Sprocket Security

Sprocket Security offers an expert-driven hybrid approach to Attack Surface Management, leveraging automation and human testers so that you get the best of both worlds. With Sprocket ASM, you have continuous access to notifications of when your attack surface changes, and can execute a plan to remediate any vulnerabilities with continuous penetration testing.

Find out more about Sprocket ASM.