How Static Application Security Testing SAST Tools Help Secure Software 

What is a Static Application Security Testing (SAST) Tool?

Static application security testing (SAST) tools analyze the source code, byte code, and binaries of an application in a static (non-running) state, checking for any potential security vulnerabilities or coding flaws. Usable in the earliest stages of development, SAST tools analyze code before the application is built, looking for weaknesses such as cross-site scripting (XSS), SQL injection, and security configuration errors. SAST tools can identify security vulnerabilities you may not be able to find just by testing the application’s front end. It can also help resolve issues more quickly, as SAST tools tell you exactly where the issue in the source code is. 

SAST and Other AppSec Testing Tools

SAST tools are only one type of AppSec testing tool available to help software developers and DevOps teams identify security flaws and protect software throughout the software development lifecycle (SDLC) — from design to runtime. Other tools that complement SAST and provide a more comprehensive picture of application security are dynamic application security testing (DAST), interactive application security testing (IAST), and software composition analysis (SCA).

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SAST and DAST

SAST tools analyze the application’s code in a static state (static code analysis), while dynamic application security testing tools test the application while it’s running (runtime). DAST takes an attacker’s approach to code, simulating attacks on applications to expose vulnerabilities. DAST can discover runtime- and environment-related issues, and help identify security gaps in code or unforeseen outcomes that could have a downstream effect on an application’s security state or the ability of an attacker to exploit application weaknesses. Since applications need to be running for DAST, these vulnerability scanning tests are typically run later in the software development lifecycle.

SAST is a white-box testing methodology, with the tester having full access to the application source code (including proprietary code, open-source or third-party code, byte code, or binary code). Some key considerations when using standalone SAST include:

• SAST requires access to the source code or compiled artifacts to perform static analysis.
• If an application uses open-source libraries but only provides compiled binaries, SAST won’t be able to scan those directly — SCA or dynamic analysis (DAST) may be needed instead. 

For these reasons, SAST should always be combined with other types of code security analysis, first and foremost, DAST.

DAST is a black-box testing methodology that assesses an application from the outside, simulating an attacker’s perspective while identifying potential security weaknesses. DAST does not require access to the source code; instead, it interacts with a running application, testing for vulnerabilities like SQL injection, cross-site scripting (XSS), authentication issues, and misconfigurations. Testers may have no or limited knowledge of the internal workings of the application, as DAST focuses on runtime behaviors rather than code structure. Some key considerations when using standalone DAST include:

• Since DAST requires a fully deployed and running application, vulnerabilities are often detected late in the SDLC when issues are harder, more time-consuming, and more costly to remediate.
• Because DAST occurs later in development, if a major security risk is found after deployment, it may require an urgent patch or a rollback, disrupting development timelines and impacting software security.

This is why, together, SAST and DAST (along with other types of automated security testing) provide a much more comprehensive picture of application security than any vulnerability testing on its own.

SAST and IAST

Interactive application security testing (IAST) combines elements of SAST and DAST. IAST is a proactive analysis technique that works from within the application to assess software in real time as it runs, providing immediate feedback on security issues by monitoring application behavior and data flow. IAST can analyze the entire application stack, including complex libraries and frameworks that often prove difficult for SAST.

SAST and SCA

Software composition analysis detects and manages potential security vulnerabilities and licensing issues across the software supply chain. SCA tools scan open-source and third-party code and dependencies for potential security issues that can lead to breaches. SCA can create a software bill of materials (SBOM), a detailed inventory of the application’s dependencies, which can be checked for known vulnerabilities and exposures. With supply chain attacks having increased 742% over the past three years, SCA is a valuable analysis tool for keeping vulnerabilities from open-source and third-party software out of an application. SCA working with SAST provides comprehensive testing of an application’s proprietary code and third-party components.

How Do SAST Tools Work?

SAST solutions can read every single line of code in an application in an offline environment, checking them against known coding errors or vulnerabilities and best practices.  The tool parses the code and creates an abstract syntax tree. The abstract syntax tree allows the tool to understand the structure of the code and helps identify potential application flaws based on predefined rules and patterns. SAST can report on the exact location of every vulnerability or anomaly, helping developers understand where security issues exist and how to fix them. Many SAST tools can integrate seamlessly into existing integrated development environments (IDEs) and continuous integration/continuous deployment (CI/CD) pipelines.

The Benefits of Static Application Security Tools

Top SAST tools provide a number of significant benefits for software development throughout the SDLC. By providing early feedback on potential issues in the code, SAST can help improve software quality and reduce the likelihood of errors and security vulnerabilities in the application. 

Early vulnerability detection: SAST can run early in the development cycle, even as code is written. Early detection not only enhances the application’s security posture but also saves time and resources by preventing extensive and costly repairs later in the SDLC.

Comprehensive code test: One of the key benefits of SAST is that it can analyze every line of code in the application, ensuring high code quality and making it a truly comprehensive test. SAST shows the exact location of every vulnerability and explains the data flow.

Secrets detection: SAST can detect active secrets in code and prioritize them based on severity and version histories. SAST tools use pattern matching and heuristics to automatically scan for secrets embedded in code. However, false positives and lack of contextual awareness plague many legacy and/or standalone SAST tools, which furthers the argument that SAST must be complemented by other types of application security testing, including purpose-built secrets detection tools.

Compliance: SAST can help developers satisfy compliance regulations and standards by ensuring code follows security best practices and requirements. Developers can use SAST to help promote coding security standards, enabling greater code integrity and faster vulnerability reduction. You can configure SAST tools to check for compliance with regulatory standards.

Integration with DevOps: Integrating SAST with DevOps processes allows the incorporation of security checks within the CI/CD deployment pipeline, providing real-time vulnerability detection and resolution without slowing down the development cycle. Developers can spend more time coding and less time fixing security problems, especially if they automate certain types of remediation.

No application execution required: Since SAST works on the source code before the application runs, it can be performed at any stage of development without creating a build file or running the application. 

Fast testing and results: SAST tools can scan millions of lines of code in minutes and automatically identify key vulnerabilities.

Easy to automate: Code can be scanned automatically at any point in the SDLC. Developers can monitor their code continuously with minimal disruption to deployment schedules.

Maintaining a stable release cycle: Including SAST tools early in your process facilitates quick resolution of security issues in the software cycle. This reduces the possibility of rework and vulnerabilities at the outset of development, resulting in smoother and more secure software releases.

Enhanced security posture: Early detection and resolution of vulnerabilities can help cultivate a security-conscious development environment without requiring developers to spend excess time focused on security security issues. With modern AppSec tools’ capabilities, developers can automate scans and resolutions, ensuring software is more secure while reducing the time and effort required to deploy secure applications.

Why Integrate SAST Tools Into the CI/CD Pipeline

Seamless integration with CI/CD pipelines allows for automatic code scanning during the development process, enabling early detection of vulnerabilities. When SAST and SCA tools are integrated into CI/CD pipelines, they can be automated to streamline communication around fixes, facilitating remediation and response processes, and reducing friction across the SDLC. This workflow automation takes the sting out of many AppSec and supply chain security processes that would otherwise be more disruptive. Pre-configured SAST analyzer images can be used with containers, allowing for easy integration into the CI/CD pipeline. The result is more secure, responsive, and efficient development, with faster version releases and greater productivity.

Six Stages of a SAST Scan

SAST should be approached systematically.  Understanding these six stages will help you get the most benefit from your testing.

1. Pre-scan preparation: Preparing for the SAST includes ensuring the tool is configured properly per your environment and testing requirements. The SAST tool acquires the codebase (source code, byte code, or binary).
2. Code parsing and analysis: SAST parses the code to understand its structure and syntax, then performs lexical and syntax analysis as well as control flow/data flow analysis.
3. Vulnerability detection: The tool performs pattern matching, taint analysis, and business logic analysis against defined rules and patterns to identify potential security vulnerabilities. Semantic analysis can help developers to understand the context and potential implications of each line of code.
4. Results processing and prioritization: The tool analyzes results, assigning severities to identified vulnerabilities to help prioritize remediation efforts and filter out false positives.
5. Reporting and remediation guidance: A modern SAST tool automatically creates a report detailing its findings, including information on identified vulnerabilities, their location in the code, their severities, and recommendations for remediation.   
6. Continuous improvement/rescanning: Developers can resolve or remediate identified vulnerabilities and then rerun the SAST to check for vulnerabilities not caught in the prior scan, or introduced by changes to the codebase. Trend analysis can also be performed.

It is important not to ignore stage six. SAST is not a one-time event. Rather it should be a continuous process of improvement and retesting to ensure maximum protection against vulnerabilities for the life of the application.

 

Finding the Right SAST Tool to Secure the SDLC

Selecting any security tool is a strategic decision that can have important implications. Before evaluating available code analysis tools, take the time to understand your environment and requirements. Here are some criteria to consider.

• Programming environment: Is the tool able to perform continuous testing in the programming environment, languages, and frameworks used by your software? Does it plug into your IDE?  To facilitate cooperation between DevOps and security, the tool should integrate seamlessly with your CI/CD pipeline and version control. 
• Vulnerability detection: Does the tool check for the OWASP Top Ten? Does it use a sufficiently large and continuously updated database of known threats and vulnerabilities? Are there other specific vulnerabilities or coding flaws you need to consider?
• Accuracy: What are the tools’ historical results? Look for a tool with high accuracy and low false positives so developers can focus on genuine and relevant threats.
• Reporting: Does the tool provide easily intelligible and actionable reports? Can it notify relevant users regarding findings?
• Source code requirements: Can the tool run against binaries in addition to source code? Does it require buildable source code?
• Ease of use/usability: How hard is the tool to configure and use? What does the anticipated learning curve look like?
• Licensing: What are the purchase/licensing configurations and costs?

Maximize Security with a Unified Application Security Testing Strategy

SAST is essential for early vulnerability detection, but it works best when combined with other security testing methods like DAST, IAST, and SCA to ensure secure code. A unified AppSec platform integrates these tools, providing comprehensive security coverage across the entire SDLC without disrupting development. 

Organizations that choose the right integrated AppSec platform will see results in the form of enhanced vulnerability detection and risk reduction, faster development lifecycles, and simplified compliance. By choosing a platform like OX Security, organizations will achieve:

• Early and continuous security: SAST detects vulnerabilities in code before deployment, reducing costly fixes later.
• Full-spectrum protection: Combining SAST with DAST, IAST, and SCA covers static, dynamic, and third-party risks.
• Seamless DevOps integration: A platform approach that automates security within CI/CD, ensuring fast and secure releases.
• Improved accuracy and efficiency: A unified security platform reduces false positives and streamlines remediation.

You can get immediate feedback and address problem code in the earliest stages of the SDLC with Ox Security’s built-in SAST tool. Click here to learn how you can bake security into your CI/CD workflow.