What is Attack Surface Analysis?

What is Attack Surface Analysis?

Attack Surface Analysis is a process of identifying and assessing the parts of a system that could be vulnerable to external attack. It is important for developers and security specialists to understand and manage the Attack Surface as they design and build an application, in order to reduce the risk of external threats. This process involves mapping out the parts of a system that need to be reviewed and tested for security vulnerabilities, and finding ways to minimize the Attack Surface. Additionally, it is important to be aware of how the Attack Surface changes, and what this means from a risk perspective. Attack Surface Analysis is typically done by security architects and pen testers, but developers should also be involved in the process.

Attack Surface Analysis can be used to identify which functions and components of a system need to be reviewed and tested for security vulnerabilities, as well as to identify areas of code that require extra protection. It can also be used to determine when changes have been made to the system which necessitate a threat assessment.

Defining the Attack Surface of an Application

The Attack Surface of an application is the sum of all paths for data/commands into and out of the application, as well as the code that protects these paths, such as resource connection and authentication, authorization, activity logging, data validation, and encoding. It also includes all valuable data used in the application, including secrets and keys, intellectual property, critical business data and personal data, and the code that protects these data (including encryption and checksums, access auditing, and data integrity and operational security controls). Additionally, you must consider the different types of users - roles, privilege levels - that can access the system (whether authorized or not). Complexity increases with the number of different types of users, so it is important to focus especially on the two extremes: unauthenticated, anonymous users and highly privileged admin users (e.g. database administrators, system administrators).

To analyze the Attack Surface, you can group each type of attack point into buckets based on risk (external-facing or internal-facing), purpose, implementation, design and technology. You can then count the number of attack points of each type, then choose some cases for each type, and focus your review/assessment on those cases. This way, you don't need to understand every endpoint in order to understand the Attack Surface and the potential risk profile of a system. Instead, you can count the different general type of endpoints and the number of points of each type. With this you can budget what it will take to assess risk at scale, and you can tell when the risk profile of an application has significantly changed.

Measuring and Assessing the Attack Surface¶

Assess the risk associated with the Attack Surface by measuring and analyzing the potential vulnerabilities. Focus on remote entry points, such as interfaces with outside systems and the Internet, that allow for anonymous public access. Pay special attention to network-facing code, web forms, files from outside the network, backward compatible interfaces with other systems, custom APIs, and security code related to cryptography, authentication, authorization, and session management.

Managing the Attack Surface

Once you have a baseline understanding of the Attack Surface, you can use it to identify and manage risks as changes are made to the application. Ask yourself: What has changed? What new approaches or technologies have been implemented? What vulnerabilities could have been introduced? By addressing these questions, you can ensure that the application's risk profile remains consistent as modifications are made.

When you create a web page, you are increasing the system's Attack Surface and introducing potential security risks. However, if you simply add another field to the same page or add another web page of the same design and using the same technology, the risk profile of the application has not significantly increased. To understand what kind of security testing and review is needed for these incremental changes, you need to determine if the change fits into an existing bucket and if the existing controls and protections apply. If not, you must conduct a more thorough risk assessment to identify any security holes and the necessary protections to put in place.

Conclusion

Attack surface management is important because it helps organizations to identify, analyze, and reduce the attack surface of their systems. By managing the attack surface, organizations can reduce their risk of being attacked and potentially compromised. It also helps organizations to identify and address potential vulnerabilities before they can be exploited by malicious actors. Additionally, attack surface management helps organizations to identify and respond quickly to any security incidents that do occur.

Our vulnerability management platform turingsecure enables you to identify and mitigate changes to your IT infrastructure, map relationships between vulnerabilities and assets, and gain insights through threat intelligence. Our platform also provides CVSS classification and vulnerability combination to help you better understand the risk and derive new strategies from the findings. With our workflows, you can gain greater transparency and better support your risk management and cyber security functions.