What is SAST in cybersecurity?

SAST is like a building inspector reviewing architectural blueprints before construction begins. Just like it's much easier and cheaper to fix a blueprint than to tear down and rebuild a house, it's far more efficient to fix code vulnerabilities during development than to patch them after a security breach in production.

SAST is important because it helps find security flaws in an app before it's released. Fixing these issues early is cheaper and easier. With SAST, developers can test and improve the app to make sure it's secure and works as expected.

When integrated into Continuous Integration/Continuous Development (CI/CD) pipelines, SAST becomes a cornerstone of "Secure DevOps" or "DevSecOps" practices. This method is frequently adopted by DevOps teams who understand that security must be built into the development process rather than bolted on afterward. If vulnerabilities are missed and the app is deployed, it can lead to data breaches, financial loss, and damage to your brand.

As we mentioned earlier, SAST works by scanning an application's source code, bytecode, or binary code to identify security weaknesses. Here's how SAST actually works under the hood, broken down into its key steps:

SAST tools first convert your source code into a structured format called an Abstract Syntax Tree (AST). Think of this like creating a detailed map of your code's architecture: it breaks down every function, variable, loop, and conditional statement into a hierarchical tree structure that the tool can systematically analyze.

The tool then performs two critical types of analysis:

• Control Flow Analysis: Maps out all possible execution paths through your code – like charting every route a user could take through your application
• Data Flow Analysis: Traces how data moves and transforms as it flows between variables, functions, and components – essentially following the "data journey" to spot where sensitive information might be mishandled

SAST tools come loaded with comprehensive security rulesets based on established standards like:

• OWASP top 10 vulnerabilities
• CWE/SANS top 25 most dangerous software errors
• Industry-specific compliance requirements
• Custom organizational security policies

The final step combines pattern matching with intelligent semantic analysis to identify problematic code patterns. The tool looks for:

• Signature patterns such as SQL query construction without parameterization
• Contextual vulnerabilities where user input flows directly into sensitive operations
• Insecure coding practices, including hardcoded credentials, weak encryption, and the use of vulnerable libraries

When applied by DevOps engineers or security specialists, this multi-layered approach in SAST helps catch vulnerabilities that simple pattern matching would miss. By combining the tool's automation with human expertise, teams can detect complex security issues where multiple seemingly harmless components create a vulnerability.

SAST and DAST (Dynamic Application Security Testing) are both used to find security issues in apps, but they work in different ways.

• SAST is a "white box" test, meaning it looks at the app's source code to find problems before the app runs. It helps developers find issues early in development and fix them before the app goes live.
• DAST is a "black box" test, meaning it tests the app while it's running, like a hacker would. It looks for vulnerabilities in the live app to see how it reacts to attacks.

In short, SAST checks the code before it's running, while DAST tests the app while it's active.

SAST tools are specialized software applications designed to automatically scan and analyze application source code for security vulnerabilities. They can either be manual or automated. Manual SAST involves security specialists reviewing the code for flaws, while automated SAST uses tools to scan the code and generate reports with detected vulnerabilities.

Some well-known SAST tools include:

SonarQube
An open-source platform that provides continuous code inspection for quality and security across multiple languages, with integration into CI/CD pipelines.

Checkmarx
Offers deep code analysis, vulnerability detection, and integrates well with DevOps tools for various programming languages

Fortify
A comprehensive SAST solution with both on-premises and cloud-based options, supporting many languages and offering detailed vulnerability detection.

Veracode
A cloud-based solution known for accurate vulnerability identification and seamless integration with development and CI/CD tools.

Coverity
A static code analysis tool by Synopsys with extensive language support and integration with development platforms.

Klocwork
Supports C, C++, C#, and Java, offering detailed code analysis, vulnerability detection, and compliance checks.

CodeScan
A Salesforce-specific SAST tool that analyzes Apex, Visualforce, and Lightning code.

GitLab Ultimate
Includes built-in SAST capabilities, providing vulnerability detection and seamless integration into GitLab's CI/CD pipelines.

PVS-Studio
Focused on C, C++, C#, and Java, offering code analysis and vulnerability detection with integration into popular development environments.

DeepSource
A code analysis platform with SAST capabilities, supporting multiple languages and integrating with version control and CI/CD pipelines.