What is active IAST
The active approach to Interactive Application Security Testing (IAST) requires two main components — a Dynamic Application Security Testing (DAST) tool and a sensor that attaches to running applications. The advantage of doing it this way instead of running just a DAST scan is that the sensors attached to the application provide additional insight into the exploit compared with the black-box nature of typical DAST findings.
During the testing phase, if the application is attacked, active IAST scans the URLs and sends them a list of known attack payloads. The sensor then monitors the application for vulnerabilities based on the incoming attack payloads. Organizations using this approach must still wait for a separate security scan to complete and receive a snapshot of their Application Security (AppSec) status.
What is passive IAST
Passive IAST is a security tool that requires a single agent to run alongside an application. It differs from active IAST, which requires actively attacking an application to identify vulnerabilities, as the passive IAST agent continuously monitors all traffic directed at the application at runtime to identify vulnerabilities. The most significant difference here is that organizations no longer need to attack an application to actively find security vulnerabilities.
The most comprehensive coverage of an application can be achieved by using existing quality assurance testing — be it manual or automated — or even by testing production use of the application. Passive IAST transforms all use of the application into a security test, making it a cost-effective and secure solution. There is no need to set up a separate infrastructure for security testing.
What is IAST?
Analyst firm Gartner has defined the IAST category as follows:
"Interactive Application Security Testing (IAST) uses instrumentation that combines Dynamic Application Security Testing (DAST) and Static Application Security Testing (SAST) techniques to increase the accuracy of application security testing. Instrumentation allows DAST-like confirmation of exploit success and SAST-like coverage of the application code and, in some cases, allows security self-testing during general application testing. IAST can be run stand-alone or as part of a larger AST suite, typically DAST."
Gartner's definition is relatively broad, allowing various solutions to be classified as IAST products.