Identifying Software Vulnerabilities: SAST vs DAST

Todays focus is on data breaches and what software engineers can do to limit them. With more using both Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST) to combat future breaches, it's important to understand the differences of the two, and why many software engineers prefer to use both when developing.

Data breaches are nothing new; creating havoc and concerning many organizations about the fiscal and business consequences of having data stolen. To better protect data, the challenge for developers is to identify where vulnerabilities may hide in their applications to mitigate risks.?Today, application security testing, such as SAST and/or DAST, are commonly added to the software development workflow.?

What’s the best method for application security testing, SAST or DAST? Many believe the answer is both.?What differentiates one from the other in the software development life cycle? Both are application security testing methodologies used by program developers to find security vulnerabilities in software applications that are susceptible to cyber attacks, but they are used for different reasons.?

SAST is a White box method of testing used to validate whether code implementation follows intended design, to validate implemented security functionality and to uncover exploited vulnerabilities in the code to find a software’s flaws or weaknesses, and should be preformed early and frequently against files containing source code. It is less expensive to perform and some consider it easier and faster when vulnerabilities are discovered to remediate them before the code enters the QA cycle. SAST typically supports all kinds of software, including web applications and web services.?

DAST is a Black box method of testing exactly what will deploy without adding a layer of software to the system. It’s a form of testing that is performed with no knowledge of a systems internals to evaluate the functionality, security and performance and other aspects of an application that examines an application’s security as it’s running, and in like-kind environment similar to production to find vulnerabilities that could be easily exploited. While DAST is more expensive to find and fix vulnerabilities, it can be done as an emergency release, finding actual “run-time” problems. But DAST can only be used on apps like web applications and web services ?

While they are different they both compliment each other, and should be carried out for comprehensive testing.?