DAST vs SAST – Dynamic Application Security Testing vs Static

In security testing, much like most things technical there are two very contrary methods, Dynamic Application Security Testing or DAST and Static Application Security Testing or SAST.

Dynamic testing relying on a black-box external approach, attacking the application in its running state as a regular malicious attacker would.

Static testing is more white-box looking at the source-code of the application for potential flaws.

Personally, I don’t see them as ‘vs’ each other, but more like they compliment each other – it’s easy to have SAST tests as part of your CI/CD pipeline with tools like Code Climate.

DAST – Dynamic Application Security Testing

There are also pros and cons for each methodology, with DAST you aren’t bound to any particular technology or language – but on the downside, you are also limited to the parts of the application visible to the outside World.

An example of such a tool would be:

– Wikto Scanner Download – Web Server Security Tool
– Spaghetti Download – Web Application Security Scanner

It’s always good to simulate attacks from the outside with the kind of access a real World attacker would have, but it doesn’t give you full visibility of the potentials flaws in your system.

SAST – Static Application Security Testing

For SAST a big con is the toolset you are using needs to be language and even framework specific, for example tools we’ve mentioned before such as:

– Brakeman – Static Analysis Rails Security Scanner
– RIPS – Static Source Code Analysis For PHP Vulnerabilities

The upside to this is that you get full oversight of the app, libraries, dependencies and parts not visible to the outside World.

IAST – Interactive Application Security Testing

There is actually a combination of the two, a form of ‘greybox’ testing that combines the DAST approach with the the SAST tooling by installing a sensor into the application itself.

A great example of this is Acunetix AcuSensor which is installed on the back-end and relays information during the DAST testing phase (so it acts as a whitebox DAST component).

You can read more in depth about this subject here:

DAST vs SAST: A Case for Dynamic Application Security Testing