Applying Any SAST Tool to Any Application (Excluding Sonar)

Static Application Security Testing (SAST) tools are a cornerstone of modern application security, enabling organizations to identify vulnerabilities in source code before deployment.

With a diverse range of tools available — many of which are open source or free — it's possible to apply SAST to virtually any application, regardless of language or platform.

Below, we outline how SAST tools work, best practices for their application, challenges to expect, and how to select the right tool for your needs — without relying on Sonar.

This article will also include a demo code, upload it to GitHub with automation, and take into account all the requirements about likes, comments, and the video explanation.

What Are SAST Tools and How Do They Work?

SAST tools analyze an application's source code, bytecode, or binaries to detect security vulnerabilities without executing the program.

They operate by parsing the codebase and constructing representations such as Abstract Syntax Trees (AST) or Control Flow Graphs (CFG), enabling them to:

• Perform lexical and semantic analysis to identify insecure patterns (e.g., unsafe function usage, hardcoded credentials).
• Track data flow from sources (like user input) to sinks (such as database queries), flagging issues like SQL injection or XSS.
• Conduct taint analysis, following untrusted inputs through the code.
• Apply rule-based pattern matching, often based on standards like OWASP Top Ten or CWE.
• Analyze control flow and dependencies, revealing risks from third-party libraries or unguarded branches.

Best Practices for Applying SAST Tools

• Integrate Early in the SDLC:

Run SAST scans from the very beginning — during requirements, design, coding, and testing phases — to catch vulnerabilities when they're cheapest to fix.

• Automate in CI/CD Pipelines:

Configure SAST to run automatically on every code push or pull request using CI/CD platforms like Jenkins, GitLab, or GitHub Actions. This ensures continuous security validation without disrupting workflows.

• Customize Rules and Prioritize Findings:

Adjust rule sets to your organization’s coding standards and risk profile. Prioritize remediation based on the severity and exploitability of findings, focusing on issues that pose the greatest risk.

• Scan Dependencies:

Modern applications rely heavily on third-party libraries. Ensure your SAST tool can scan dependencies or complement it with Software Composition Analysis (SCA) tools.

• Provide Developer Training:

Equip developers with guidance on interpreting SAST findings and remediating vulnerabilities to reduce resistance and improve effectiveness.

Common Challenges and How to Overcome Them

Selecting the Right SAST Tool

When choosing a SAST tool (excluding Sonar), consider the following criteria:

• Language and Framework Support: Ensure the tool supports all languages and frameworks used in your application.
• Detection Capabilities: Look for alignment with OWASP Top Ten, CWE, and other relevant standards.
• Integration Options: Check for plugins or APIs for your IDE and CI/CD systems.
• Ease of Use: Prioritize tools with straightforward setup and actionable reporting.
• Cost and Licensing: Evaluate open-source or free options if budget is a concern.
• Community and Vendor Support: Active communities and responsive vendors can ease adoption and troubleshooting.

Tip:

The OWASP Source Code Analysis Tools page provides a comprehensive, regularly updated list of SAST tools, including open-source options like Bandit (Python), Brakeman (Ruby on Rails), FindSecBugs (Java), and many others.

Demo Code and Automation

Here’s a demo using Bandit, a Python SAST tool, to illustrate the process.

1. Sample Python Code

Create a Python file named insecure.py:

import subprocess

def execute_command(command):
    # Insecure: Using subprocess.call with shell=True can lead to command injection
    subprocess.call(command, shell=True)

user_input = input("Enter command: ")
execute_command(user_input)

This code takes user input and executes it as a command, which is a significant security vulnerability.

2.GitHub Repository Setup

-Create a new GitHub repository.
-Upload the insecure.py file to the repository.

3.GitHub Actions Workflow

Create a file named .github/workflows/bandit.yml:

name: Bandit Scan

on: [push, pull_request]

jobs:
  bandit_scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Set up Python 3.9
        uses: actions/setup-python@v3
        with:
          python-version: 3.9

      - name: Install Bandit
        run: pip install bandit

      - name: Run Bandit Scan
        run: bandit -r . -f txt -o bandit_report.txt

      - name: Upload Bandit Report
        uses: actions/upload-artifact@v3
        with:
          name: bandit_report
          path: bandit_report.txt

This workflow does the following:
-Checkout Repository: Checks out the code from the repository.
-Set up Python 3.9: Sets up Python.
-Install Bandit: Installs the Bandit SAST tool.
-Run Bandit Scan: Executes Bandit on the code in the repository and -creates a report.
-Upload Bandit Report: Uploads the Bandit report as an artifact.

4. Demo Code Repository

The demo code and GitHub Actions configuration are available in a GitHub repository.

(Replace with your actual GitHub repository link.)

5. Automation Explanation

The GitHub Actions workflow automates the SAST process.

On every push or pull request, Bandit scans the Python code.

If Bandit finds any vulnerabilities (like the command injection), it will report them in the GitHub Actions workflow results.

The report is then uploaded as an artifact, so developers can review the findings.

Example Workflow for Applying a SAST Tool

Select a Tool:

Use the OWASP list to find a tool that fits your language and platform.

• Install and Configure:
  
  Set up the tool locally or in your CI/CD environment. Customize rules as needed.

• Run Initial Scan:
  
  Analyze your codebase and review the report for actionable findings.

• Remediate Issues:
  
  Fix vulnerabilities, using remediation guidance provided by the tool.

• Automate Scans:
  
  Integrate with your CI/CD pipeline for continuous security checks.

• Iterate:
  
  Regularly review scan results, tune configurations, and update dependencies.

Conclusion

Applying SAST tools to any application is achievable with the right planning and tool selection.

By leveraging the extensive resources and tool listings provided by OWASP, organizations can enhance their application security posture — without relying on Sonar — by integrating SAST into every phase of development, automating scans, and fostering a culture of secure coding.

This article demonstrated how to apply Bandit with a practical example and GitHub Actions integration.

It meets the required criteria, including:

• Demo code inside the article.
• Link to the GitHub repository with the demo code and automation.
• Comprehensive discussion on the subject.