SAST vs SCA

What is a SAST tool?

Static Application Security Testing (SAST) is a static application analysis technique used to examine the source code or bytecode of an application without executing it, to identify security vulnerabilities in the code. 

Contrast Security complements SAST by providing real-time, runtime application security testing that integrates into applications to detect vulnerabilities dynamically during execution. The Contrast Security approach to application security reduces false positives, improves accuracy and accelerates remediation by pinpointing exploitable issues, enhancing developer efficiency and application security.

What is an SCA tool?

Software Composition Analysis (SCA) is a method to check software to look for open-source components. It helps developers find security risks associated with these components, find outdated versions or license issues.

What are the differences between SAST and SCA?

In cybersecurity, the fundamental difference between SAST and SCA testing techniques lies in their approach. SAST is a static analysis technique that examines the source code or bytecode of an application without executing it. This provides initial insights into vulnerabilities but limits its ability to find vulnerabilities that only appear during application runtime. SAST tools may also report vulnerabilities that are not exploitable in runtime, leading to false positives that increase the workload of teams evaluating and fixing vulnerabilities.

Software Composition Analysis (SCA) is a method used to check the components of software, especially open-source libraries, to ensure they are safe and meet requirements. 

SCA works by scanning software application components and comparing them to a database of known vulnerabilities and licenses. When it finds a problem, like a bug in a library, it alerts developers so they can update or replace it. This process helps keep software secure and compliant with rules about how code can be used.

One big advantage of SCA is that it quickly identifies risks in third-party code, saving time and reducing manual work. It also helps maintain legal compliance by flagging license violations. However, a disadvantage is that it focuses only on external components, not custom-written code, so you may still have risks there.

SCA differs from SAST. SAST examines custom-written code for security flaws, while SCA looks at external libraries. Using both tools together ensures better protection, as they cover different parts of the software development process.

Why is SAST important?

The importance of SAST lies in its ability to analyze the source code, bytecode or binary code without executing the program, thereby detecting potential security flaws such as buffer overflows, SQL injection and cross-site scripting before they can be exploited.

SAST provides developers with immediate feedback, empowering them to fix issues as they arise, which reduces the cost and complexity of remediation. SAST also helps in maintaining compliance with industry standards and regulations by identifying vulnerabilities that could lead to non-compliance. SAST tools often integrate seamlessly with development environments, making it easier for developers to adopt security best practices without disrupting their workflow.

Why is SCA important?

The importance of SCA centers around its capacity to identify vulnerabilities within open-source and third-party components, which are often integrated into proprietary software. This proactive approach decreases the risk of exploits and data breaches by keeping developers informed about emerging threats and providing solutions for remediation.

One of the key benefits of SCA is its ability to streamline the license management process, helping organizations avoid legal complications that arise from unintentional misuse of open-source licenses. Additionally, SCA enhances transparency and accountability, offering insights into the quality and security of the software supply chain. Ultimately, by automating these checks, SCA allows developers to focus more on innovation and less on manual compliance tasks, thus accelerating the overall software development lifecycle.

How does SAST work?

SAST tools work by examining the code and comparing it against a database of known vulnerability patterns. The analysis begins with a thorough scan of the entire codebase, detecting vulnerabilities such as buffer overflows, SQL injections and cross-site scripting. These tools use static analysis techniques, including data flow analysis and control flow analysis, to trace how data moves through the code and identify areas where security breaches could occur.

SAST is a static testing methodology focused on analyzing source code, binaries or bytecode for security vulnerabilities without executing the application. It is typically integrated early in the software development lifecycle (SDLC) to identify issues such as insecure coding practices, logic flaws, or potential injection points before deployment. 

In comparison, runtime application security, as exemplified by Contrast Security, works in a dynamic, live environment by monitoring and protecting applications during execution. While SAST operates offline and is proactive, focusing on prevention, Contrast Security operates in real time, providing defense against attacks as they occur. This key difference highlights how SAST emphasizes early detection, often with limited context, while runtime solutions focus on immediate mitigation and protection.

Setup and implementation

1. Integration: SAST tools are integrated into the development environment or CI/CD pipeline. This integration allows for continuous scanning of code as it is written and updated.
2. Configuration: Developers configure the SAST tool to reflect the specific security standards and regulatory requirements of their industry.
3. Baseline scan: An initial scan is conducted to establish a security baseline. This scan identifies existing vulnerabilities, which are then prioritized and remediated.
4. Continuous scanning: As new code is developed, the SAST tool continuously scans for vulnerabilities, providing real-time feedback to developers.
5. Reporting: The tool generates detailed reports highlighting identified vulnerabilities, their severity and remediation guidance.

What type of vulnerabilities does SAST detect?

SAST is adept at identifying a wide array of vulnerabilities in an application's code during the development phase. Among the most prominent types of vulnerabilities that SAST can detect are:

• SQL injection: This occurs when an attacker can manipulate a query by injecting malicious SQL code into input fields, potentially gaining unauthorized access to the database.
• Cross-site scripting (XSS): This happens when malicious scripts are injected into webpages viewed by users, which can lead to unauthorized actions on behalf of the user.
• Buffer overflows: These occur when a program writes more data to a buffer than it can hold, which can cause crashes or enable arbitrary code execution.
• Insecure dependencies: SAST tools can flag the use of outdated or vulnerable first-party code but not third-party libraries, which are often precompiled or hosted externally, limiting SAST's ability to evaluate vulnerabilities within these dependencies.
• Hardcoded secrets: These include passwords, API keys or tokens embedded directly in the code, which pose serious security risks.
• Code injection: This involves the introduction of malicious code into a vulnerable application, allowing an attacker to execute arbitrary commands.

However, there are certain types of vulnerabilities that SAST cannot detect:

• Runtime vulnerabilities: SAST analyzes code in a static state and cannot detect issues that only arise during execution.
• Business logic flaws: These are specific to the application's intended functionality and are often too contextually complex for SAST tools to identify.
• Configuration errors: Mistakes in deployment or environmental settings are outside the scope of SAST.

How does SCA work?

SCA tools analyze the software's source code, binaries and dependencies to create a detailed inventory of all open-source components. These tools cross-reference this inventory against known vulnerability databases, such as the National Vulnerability Database (NVD), to identify any security risks. Additionally, they check for license compliance, ensuring that the usage of open-source components aligns with the organization's legal requirements.

Setup and implementation

1. Integration: SCA tools are integrated into the CI/CD pipeline or development environment, allowing for continuous monitoring and analysis of open-source components as they are introduced and updated.
2. Configuration: Developers configure the SCA tool to align with the organization's security policies and compliance requirements, defining which licenses are acceptable and setting vulnerability thresholds.
3. Baseline scan: An initial scan is conducted to identify and document all open-source components within the codebase, establishing a security and compliance baseline.
4. Continuous monitoring: As new code is added or existing code is modified, the SCA tool continuously scans for vulnerabilities and compliance issues, providing real-time alerts and detailed reports.
5. Remediation: When vulnerabilities are found, the tool alerts developers and provides information on how to address the issue by updating components to safer versions.

What type of vulnerabilities does SCA detect?

SCA is adept at identifying security vulnerabilities, outdated dependencies and license compliance issues in the open-source components of a software application. Here are the key vulnerabilities that SCA can detect:

• Known vulnerabilities: SCA tools cross-reference the components in your software with databases like the NVD to identify known security vulnerabilities.
• Outdated dependencies: SCA scans for outdated libraries and frameworks that might contain security patches in newer versions.
• License compliance issues: SCA ensures that the open-source components comply with the desired licenses, reducing legal risks.
• Cryptographic errors: These include weak or deprecated algorithms used in the open-source components.
• Dependency conflicts: SCA identifies conflicts between versions of dependencies that could lead to security issues.

However, there are certain vulnerabilities that SCA cannot detect, which are better handled by other security tools such as SAST:

• Code logic errors: SCA cannot analyze the proprietary code logic of an application.
• Runtime vulnerabilities: Issues like memory leaks or improper error handling that arise during the execution of the code need other tools to detect.
• Business logic flaws: These contextual vulnerabilities related to the specific functionality of an application are outside the scope of SCA.

When should a company use SCA vs SAST?

When to use SAST

SAST is best utilized during the early stages of development when the code is being written and reviewed. Since SAST analyzes the source code, bytecode or binary code, it helps developers detect vulnerabilities such as SQL injection, buffer overflows and cross-site scripting before the application is executed. Integrating SAST into the CI/CD pipeline allows for continuous monitoring and immediate feedback, enabling developers to fix issues on the spot. This proactive approach minimizes the cost and complexity of remediation and ensures that vulnerabilities are addressed before the code progresses to later stages.

When to use SCA

SCA should be implemented whenever open-source components or third-party libraries are used within the software. This is crucial because modern applications often rely on numerous third-party components. SCA scans the codebase to identify vulnerabilities, outdated dependencies and license compliance issues, ensuring the security and legality of the integrated components. SCA is especially vital during initial development to establish a secure baseline, as well as during updates and maintenance phases to manage ongoing risks.

Using SAST and SCA together

Using SAST and SCA together provides a comprehensive approach to securing software throughout its development lifecycle. When deployed in tandem, these tools address both proprietary code vulnerabilities and issues stemming from third-party components, thus ensuring a robust security posture.

Benefits of using SAST and SCA together

1. Enhanced security coverage: SAST focuses on identifying vulnerabilities within the custom code developed by the organization. Meanwhile, SCA inspects open-source and third-party components for known vulnerabilities, outdated dependencies and license compliance issues. By combining both, organizations can address a broader spectrum of security risks.
2. Early detection and remediation: Both SAST and SCA can be integrated into the CI/CD pipeline, providing continuous monitoring and immediate feedback. This early detection mechanism ensures that security vulnerabilities are identified and fixed at the earliest stages of development, reducing the cost and effort required for remediation later on.
3. Streamlined compliance: SAST helps in maintaining compliance with industry standards and security regulations by ensuring the proprietary code is free from vulnerabilities. SCA verifies that open-source components adhere to acceptable licenses and do not introduce legal risks. Together, they simplify the compliance process and provide a comprehensive audit trail.

How to deploy SAST and SCA together

1. Integration into CI/CD Pipeline: Integrate both SAST and SCA tools into the CI/CD pipeline. This allows for continuous scanning of both custom and third-party code. Tools can be configured to run automatically during code commits, builds and deployments.
2. Configuration: Customize the SAST and SCA tools based on the organization’s security policies and compliance requirements. Define acceptable vulnerability thresholds, license policies and remediation workflows to ensure alignment with organizational standards.
3. Baseline scans: Conduct initial scans using both SAST and SCA to establish a comprehensive security baseline. This helps identify existing vulnerabilities and compliance issues that need to be addressed upfront.
4. Continuous monitoring and reporting: Enable continuous monitoring capabilities to keep an eye on new code changes and updates. Both SAST and SCA tools should generate detailed reports highlighting vulnerabilities, their severity, and remediation guidance, making it easier for developers to address issues promptly.

By leveraging both SAST and SCA together, organizations can ensure a more secure and compliant software development process, ultimately leading to more robust and reliable applications.

Relying on traditional application security testing (AST) solutions like SAST too frequently leads to headaches and insecure web applications. For more information on why, check out this infographic.