What is an attack surface? A definition and best practices to reduce it

What is an attack surface and what best practices can help to minimize it? Cyberattacks and data breaches are incredibly expensive and can cause customers to lose confidence in a business. It’s in every organization’s best interest to limit those risks as much as possible. One of the key steps to take to avoid cybersecurity breaches — and the headaches that come along with it — is to reduce organizational attack surfaces. 

What is an attack surface?

What is an attack surface? An attack surface is defined as a set of all possible locations and entry points where an unauthorized user can access a network or system to extract data or cause a cyberattack.

For example, a business’ attack surface can include the company website, VPN and intranet, as well as ports, software platforms and servers.

As more technologies and software are added to a business, a larger potential attack surface is created. So, as businesses add new resources and users, they must constantly be on guard to prevent potential threats to those resources.

What are the different types of attack surfaces?

There are typically three different types of attack surfaces:

• Digital Attack Surfaces
  • Digital attack surfaces are made up of the components that connect to an organization’s network. Software applications, ports, servers, websites and Shadow IT components (apps used without the IT team’s permission) are all part of the digital attack surface.
• Physical Attack Surfaces
  • Physical attack surfaces are made up of physical devices and endpoints where an unauthorized user could gain access. Laptops, desktops, cell phones, tablets, printers and USB drives are all considered to be physical attack surfaces.
• Social Attack Surfaces
  • Social attack surfaces involve gaining the trust of an individual or group to be granted access outside of organizational policies. For example, an attacker gaining access through social connections to a contractor that frequently works with staff.

What is an attack vector?

An attack vector is the method unauthorized users use to access organizational systems. For example, a phishing email may be the attack vector used to gain access to other sensitive company data.

How are attack vectors and attack surfaces related?

Attack surfaces and attack vectors are different but related concepts that often get confused. Attack vectors are the methods an unauthorized individual uses to breach or access an organization’s systems or accounts, such as via unpatched software, weak web components, expired certificates and public dev sites. Attack surfaces are the organization’s systems and accounts that get attacked or breached.

For example, an attack vector would be a cybercriminal using an unencrypted API to breach company network systems to steal employee data. In this scenario, an attack surface would be the company’s network systems.

Every digital or physical attack surface can be accessed through a wide variety of attack vectors, and organizations frequently have dozens or hundreds within its network. The most common attack vectors include, but are not limited to:

• Phishing: A technique used to acquire sensitive data through fraudulently sent messages that look legitimate
• Malware: An intentionally damaging program that is included or inserted into a system
• Ransomware: A type of malware designed to lock down systems and networks that is only released after a demand for money
• Compromised passwords: Stolen or weak passwords can give bad actors nearly effortless access to systems and applications
• Encryption issues: Encryption is designed to mask data from being easily decipherable if it’s intercepted. Unencrypted data is much more susceptible to theft since it is unprotected
• Unpatched software: Older software versions may have vulnerabilities that, if not patched or updated, cyber attackers can exploit to gain access to systems
• Social engineering: Cybercriminals will take advantage of internal team members by leveraging social pressure and interpersonal situations to gain access to sensitive data
• Unsecure APIs: If application programming interfaces aren’t secured, hackers can get control of organization’s data and functionality

The attack surface reduction principle

The attack surface reduction principle is the idea that limiting an organization’s attack surface gives fewer entry points to would-be cyber attackers to access sensitive data.

Think of it like shooting at a target. A smaller target is hard to hit, and hitting a moving target is even more difficult.

The fewer vulnerabilities available for unauthorized users to access means internal teams have fewer resources they need to maintain and monitor. By extension, less enticing for attackers.

What is attack surface management and why is it important?

Attack surface management is an ongoing task in a comprehensive cybersecurity risk management program where attack surfaces are constantly analyzed, investigated, maintained and monitored to mitigate potential cyberattacks. Its overall goal is to identify potential vulnerabilities so that there are fewer entry points for a breach.

Organizations that are unaware of their various attack surfaces have no insight into their potential vulnerabilities and place themselves at a significant disadvantage in the event of an attack.

For entities that actively manage their attack surfaces, an attack surface analysis is crucial to gain a full understanding of potential weaknesses.

Conducting an attack surface analysis

An attack surface analysis maps out all potential security vulnerabilities within a network. It isn’t a quick fix, however it gives a more accurate map of where to get started to protect digital assets. Conducting an attack surface analysis and charting out potential vulnerabilities is key to tightening up security protocols to make an organization safer and more secure. An attack surface analysis often includes:

• Identifying all attack surfaces
  • Start to get a handle on all potential systems that can leave the organization open to vulnerabilities. Map out applications, APIs, endpoints, databases and sites that attackers could potentially use to get into an organization’s system.
• Identifying all entry points (which can be thousands or more)
  • For each attack surface, there may be multiple potential entry points. Across hundreds of applications in an organization, that makes for lots of entry points. To make this exercise a bit easier, consider categorizing each entry point based on function, design and technology. For example, bucketing together logins, admin interfaces, and APIs makes it easier to determine the types of entry points that are potential vulnerabilities.
• Identifying high risk areas, with a focus on exterior systems that allow public access.
  • Once potential entry point vulnerabilities are identified, prioritize assessing what controls are in place over systems that allow public access. Custom APIs, web forms, and backward compatible interfaces are of particular risk, and where organizations are most exposed.
• Defining user types and privilege levels
  • Who can access what applications? When can they access them? Each organization has varying user types and privilege levels needed for work and day-to-day activities to move forward. User types and roles should be assessed across attack surfaces to ensure individuals have appropriate privilege levels and application access.
• Prioritizing potential risks
  • After identifying and analyzing potential risks, the next step is to prioritize the areas of the highest potential vulnerability.
• Identifying a breach or compromised system
  • In the event of a data breach or compromised system, how will the team know? Evaluate current controls, workflows and procedures to make sure any breaches are handled and responded to quickly and appropriately.

Attack surface evaluations aren’t simply a one and done task. As enterprises shift—by adding and removing users, tools, systems and interfaces—overall attack surfaces will grow and change, making an attack surface analysis an ongoing process. Pair periodic evaluations with regularly scheduled tasks aimed at minimizing potential attack surfaces to help keep vulnerabilities in check.

How to minimize attack surfaces: Six key strategies

One common way organizations start to reduce their cybersecurity risk is by minimizing their attack surfaces. Keep in mind that reducing the number of these areas is a helpful start, but it doesn’t mean that vulnerabilities still can’t be exploited. Consider these key methods to start minimizing organizational attack surfaces:

• Get rid of unused or unnecessary software and endpoints
  • Unused software and endpoints are ripe for exploitation. If an application or endpoint is no longer frequently accessed or needed, take steps to sunset their usage.
• Implement Zero Trust
  • Zero Trust is a cybersecurity philosophy that hinges on the idea that no user inside or outside of a network is trusted. Authentication, network segmentation, preventing lateral movement and limiting access to only necessary applications are the fundamental foundations for this approach to cybersecurity.
• Provide cybersecurity training for employees
  • Cybersecurity training for employees offers another line of defense against attackers. Trainings that help employees understand best practices can also help mitigate breaches from phishing emails and social engineering attempts.
• Conduct regular vulnerability scans
  • Periodic attack surface scans help organizations quickly find and identify potential exposure points.
• Protect backups
  • Old backups and copies of data are often included as part of a company’s overall attack surface. Protection protocols and access to that data should be strictly limited to help ensure they don’t become exploited.
• Segment your network
  • By dividing networks into smaller pieces, organizations can add hurdles to would-be attackers. Network segmentation actions such as micro-segmentation — isolating specific areas and setting up zero trust for that area — and firewalls help to maintain some distance between specific sections of an attack surface.

Attack surface management is no small task. However, by taking steps to conduct an attack surface analysis and minimize attack surfaces, organizations can help mitigate the heavy cost of a breach.

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