Attack Surface Reduction Explained

What is attack surface reduction?

Technologies like cloud computing, the Internet of Things (IoT), mobile phones, and microservices have completely revolutionized the software industry over the last decade. Developers are building, deploying, and scaling applications in ways that unlock unprecedented connectivity and innovation. Along with this increase in developer productivity came a drastic increase in digital assets deployed across an enterprise. 

While the productivity gains from digitization are undeniable, an increase in digital assets means an increase in attack surface. With each new smart device and the adoption of XaaS (everything as a service) comes an increased risk of vulnerabilities, as each component presents a potential entry point for malicious actors to penetrate an environment. As a result, balancing attack surface reduction with developer productivity and user experience has become one of the main security challenges of modern software development. 

This article explores the core principles of attack surface reduction to help you understand which tools and techniques have proven most effective, and how teams can implement them.

Understanding attack surface

An attack surface is the sum of all entry points into a system that an attacker may exploit. For each of these entry points, attackers may have multiple methods to breach a system (also known as attack vectors).

In cloud-native environments, attack surfaces are dynamic and constantly changing. As infrastructure scales up and down, new services are deployed and old ones are decommissioned. This fluctuation introduces new components that present potential attack vectors and increase risk. 

To kick off an attack surface reduction initiative, teams should categorize attack surface components such as:

• Internal and external assets: Infrastructure components such as virtual machines, databases, and devices that can run either in an internal network or one that is publicly accessible.
• Cloud environments: Cloud infrastructure, platforms, and software are managed by cloud providers but must be configured by cloud and security engineers to meet security standards.
• Shadow IT: Tools used by employees without the organization’s knowledge or authorization often lack basic security configurations. 
• Third-party services: External tools, application program interfaces (APIs), and platforms provided by vendors may fail to meet an organization’s security and compliance requirements. These tools may also rely on other third-party solutions, creating a chain of dependencies and risk.
• Identity and access: Identity-based access structures such as users, groups, roles, permissions and others, that define who can interact with sensitive assets and data.

Core principles of attack surface reduction

Organizations engaging in these categorization exercises will quickly realize that minimizing an attack surface is complex. Fortunately, proven attack surface reduction principles can guide organizations as they make critical implementation decisions. 

Optimize for visibility

Awareness is a critical prerequisite for attack surface reduction. Many entry points, such as third-party and shadow IT components, are not easily visible to a security team. Therefore, continuous, real time discovery and investigation are required to maintain an up-to-date attack surface registry.

Be proactive 

Any mistake in cybersecurity can be catastrophic or cause permanent damage, so only taking reactive approaches is high risk. For this reason, find the right balance between investing in reactive and proactive security approaches, without neglecting either.  

Attack surface reduction is one part of a proactive approach to security, with examples such as zero trust and network segmentation. These practices not only reduce the probability of a successful attack but also significantly limit the blast radius should one occur. 

Reduce exposure

Cybersecurity is often a numbers game. By reducing your exposure, you increase the cost of a successful breach for the adversaries. Teams can limit attack surface and minimize exposure using practices such as: 

• Identify unprotected systems: Find unprotected systems and harden them with security configurations or compensating controls.

• Remove unnecessary services: Remove web services that are running but are not required and block unused network ports. 

• Enforce the principle of least privilege (PoLP): Employees and stakeholders should only have access to the resources and tools essential for performing their tasks. 

• Decommission outdated systems: Outdated systems should be regularly updated and decommissioned once they reach end of life (EoL) or end of support (EoS). 

Practical attack surface reduction techniques

The techniques below help teams implement the principles discussed above and effectively reduce attack surface in modern networks. 

Continuously monitor new assets

Continuously monitor the addition of new assets, accounts, and applications in your environment, assess weakness in their posture, and remediate them. For instance, monitor your network for unprotected systems such as a server missing endpoint security agents and fix them.

Eliminate unnecessary assets

Teams should immediately decommission unused hardware, software, third-party tools, and other digital assets. In addition to attack surface reduction and cost savings, removing these assets will reduce monitoring and security patching overhead. 

Implement patch management

Organizations should regularly scan production services for vulnerabilities and ensure they are patched as needed. Software applications often use many third-party libraries, which may contain hidden vulnerabilities and serve as entry points for attacks. This is why regular scanning is required, even if no code updates have been introduced since the last successful scan.

Enforce network segmentation

Network segmentation is a technique used to isolate endpoints that do not need to communicate with one another. It ensures that even if a network breach occurs, it is limited to a small number of assets, and east-west movement is contained. Segmentation should follow PoLP, meaning components should not interact with one another unless necessary. 

Follow cloud security best practices

Strong security hygiene is essential. Organizations should enforce the practices below across their digitally-enabled systems and processes. 

• Create and maintain robust security configurations: Enforce strong security policies and configuration management through Infrastructure-as-Code (IaC), PoLP access controls, and strict firewall rules.
• Continuously monitor critical assets: Implement real-time monitoring of infrastructure, application code, and audit logs in cloud environments to detect anomalies, unauthorized access, and suspicious activities.
• Encrypt and secure sensitive data: Encryption of data in transit and at rest is a cornerstone of data confidentiality and integrity. Store secrets in encrypted formats and regularly rotating their values. 
• Secure identities across the organization: Enforce identity and access management (IAM) best practices such as multi-factor authentication (MFA), PoLP, and well-defined service roles.

Leveraging tools for attack surface management

While the continuous expansion and integration of technology create significant innovation and convenience, it also increases the attack surface and opportunity for threat actors. 

Reducing your organization’s digital attack surface will significantly reduce the risk of a breach. However, getting attack surface reduction right requires process discipline, organizational buy-in, and industry-leading security tools to achieve maximum effectiveness. 

CrowdStrike Falcon Exposure Management supports the fortification of organizations’ cyber defenses by providing out-of-the-box features, such as continuous asset discovery, real-time vulnerability prioritization, and automated remediation. 

By integrating cutting-edge AI technologies, CrowdStrike Falcon intelligently prioritizes critical vulnerabilities and streamlines patch management. With continuous 24/7 monitoring, CrowdStrike Falcon detects new exposures as systems scale in real time, ensuring no new vulnerabilities remain undetected.