How to reduce False Positives in SAST?

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Static Application Security Testing (SAST) is crucial for identifying security vulnerabilities in code before deployment. However, a significant challenge with SAST tools is the high prevalence of false positives, with up to 50% of findings being erroneous if the tool is not properly configured​​. These false positives can severely impact both development and security teams, consuming valuable time and resources. On average, each false positive can take 15 to 30 minutes to triage, creating a substantial drain on productivity​​, especially when a company has tens of thousands of vulnerabilities identified.

For developers, this time spent on false positives detracts from writing and improving code, leading to alert fatigue and desensitization to security alerts. For security teams, the additional noise from false positives makes it harder to prioritize and address real threats, reducing overall efficiency and potentially leaving genuine vulnerabilities unaddressed​.

Addressing the issue of false positives requires a multi-faceted approach. Proper configuration of SAST tools, incorporating contextual information, and leveraging advanced technologies such as AI and large language models (LLMs) are essential. By optimizing SAST scanners and enhancing their contextual understanding, organizations can significantly reduce false positives, leading to more efficient and accurate security practices​.

Understanding False Positives in SAST

What Are False Positives?

A false positive in the context of SAST is an alert or finding that incorrectly identifies a security vulnerability in the code. These findings are flagged as potential threats, but upon closer inspection, they are determined to be non-issues. False positives can arise from various factors, including tool configuration, lack of contextual understanding, and nuances within specific programming frameworks.

Common Causes of False Positives

  1. Unoptimized SAST Scanners: Many SAST tools come with default settings that may not be fine-tuned to the specific needs of a project or organization. Without proper optimization, these tools can generate a high volume of false positives.

  2. Lack of Contextual Awareness: SAST tools often lack the ability to understand the broader context in which code operates. For instance, a tool might flag hard-coded secrets in a test suite as vulnerabilities without recognizing that they are harmless in this specific context. Additionally, some companies might have custom controls or middleware to handle specific vulnerabilities that the scanners are unaware of.

  3. Framework-Specific Issues: Different programming frameworks have their own unique characteristics and security mechanisms. A SAST tool that is not tailored to understand these nuances may misinterpret safe code as a security risk. For example, a SAST tool might flag the use of certain functions in Django as potential cross-site scripting (XSS) vulnerabilities without recognizing that Django’s template engine automatically escapes variables to prevent XSS.

  4. Inclusion of Third-party Libraries: Companies used to include third-party code into their applications before package managers became widely adopted. Unfortunately, SAST scanners are unable to differentiate between first-party and third-party code when scanning leading to a lot of noise for developers.

Real-World Examples of False Positives

Consider a scenario where a SAST tool flags a hard-coded cryptographic key as a security vulnerability. While this is generally a good practice, it becomes a false positive if the key is part of a test suite and not used in production. Similarly, a SAST tool might flag a potential SQL injection vulnerability without understanding that the input is sanitized by the application logic, leading to another false positive. These examples illustrate the importance of contextual understanding in accurately identifying true security risks.

The Cost of False Positives

Time and Resource Wastage

The most immediate cost of false positives is the wastage of time and resources. Developers and security teams must spend considerable effort investigating and triaging these erroneous findings. The time taken to review each false positive—often ranging from 15 to 30 minutes—can quickly add up, diverting attention away from genuine security issues and critical development tasks.

Alert Fatigue Among Developers

Constantly dealing with false positives leads to alert fatigue among developers. When developers are inundated with numerous false alerts, they may start to overlook or ignore SAST findings altogether. This desensitization to alerts can result in genuine vulnerabilities being missed, ultimately compromising the security of the application.

Comments like this capture the zeitgeist of SAST scanning.

Impact on Security Team Efficiency

For security teams, false positives create additional work that detracts from their primary responsibilities. Instead of focusing on real threats and improving overall security posture, security professionals must sift through a myriad of false alerts. This not only reduces their efficiency but also increases the likelihood of missing critical security issues that require immediate attention.

Threads like this are very common in the security community.

Consequences for Software Quality and Security

The cumulative effect of false positives on software quality and security is significant. When development and security teams are bogged down by false alerts, their ability to deliver secure and high-quality software is compromised. False positives can lead to longer development cycles, increased costs, and a higher risk of security breaches due to overlooked vulnerabilities. Addressing false positives is thus not only a matter of efficiency but also of maintaining the integrity and security of software applications.

Best Practices for Reducing False Positives

To minimize false positives, it is crucial to properly configure your SAST tools. Start by tailoring the tool settings to match the specific requirements of your project. This involves customizing the rules and policies to align with your codebase and security objectives. Adjusting sensitivity levels, excluding non-critical paths, and focusing on high-risk areas can significantly reduce the volume of false positives.

Additionally, ensure that the SAST tool is integrated seamlessly into your development pipeline. This integration allows for continuous scanning and immediate feedback, helping developers address potential issues as they code. Proper configuration and integration of SAST tools lay the foundation for accurate and efficient vulnerability detection.

Incorporating Contextual Information

One of the key reasons for false positives is the lack of contextual awareness in SAST tools. To address this, it is important to incorporate contextual information into the scanning process. This can be achieved by providing the SAST tool with relevant data about the codebase, such as usage patterns, project-specific configurations, and framework-specific nuances.

For example, the SAST scanner identified this vulnerability as Exposure of Private Personal Information to an Unauthorized Actor. Unfortunately, this is a false positive finding as this relates to a script in a test-suite.

For instance, by informing the SAST tool about certain test suites or safe coding practices within the project, you can prevent it from flagging benign code as vulnerabilities. Contextual information helps the tool differentiate between actual security risks and false positives, leading to more accurate results.

Framework-Specific Adjustments

Different programming frameworks have unique characteristics that can affect the accuracy of SAST tools. Make framework-specific adjustments to fine-tune the tool for better performance. For example, certain functions or methods in a framework may have built-in security mechanisms that prevent common vulnerabilities. Informing the SAST tool about these mechanisms can prevent it from flagging false positives.

For example, here we can see the SAST scanner identifying an XSS issue. Unfortunately, this is a false positive as the project using Django's `render_to_string` function, which automatically escapes variables to prevent XSS.

Work closely with developers to understand the specific security features and best practices of the frameworks used in your projects. By tailoring the SAST tool to account for these framework-specific nuances, you can significantly reduce the incidence of false positives.

Regular Updates and Maintenance of SAST Scanners

SAST tools, like any software, require regular updates and maintenance to remain effective. Keep your SAST scanner up to date with the latest security rules, vulnerability databases, and engine enhancements. Regular updates ensure that the tool can recognize new and emerging threats while maintaining accuracy in identifying false positives.

In addition to updates, perform periodic reviews and audits of the SAST tool’s performance. Analyze the false positive rates and make necessary adjustments to improve accuracy. Continuous maintenance and updates are essential for keeping your SAST tool effective and reliable.

Continuous Monitoring and Improvement

Implementing Advanced False Positive Detection is not a one-time task. Continuous monitoring and improvement are essential to maintain accuracy and effectiveness. Regularly review the false positive rates and make necessary adjustments to improve detection accuracy.

It is important to generate a report that shows pattens of false positives like the one below. As you can see, there's an extremely high number of false positives with Hard-coded Passwords and SQL injection vulnerabilities. It would be wise to find-tune the scanner to reduce those over time, and continue to monitor this.

Stay informed about the latest advancements in AI and static code analysis techniques. Incorporate new methodologies and tools into your workflow to stay ahead of emerging threats. By continuously monitoring and improving your false positive detection capabilities, you can maintain a secure and efficient development process.

Advanced Techniques for False Positive Detection

Static code analysis is a method of examining source code without executing it. This technique is used to identify potential security vulnerabilities, code quality issues, and compliance violations. While static code analysis is a powerful tool, its effectiveness is often limited by the high rate of false positives. Advanced techniques are required to enhance its accuracy.

Leveraging AI and LLMs for Contextual Understanding

Artificial Intelligence (AI) and Large Language Models (LLMs) have revolutionized the way false positives are detected. By leveraging these technologies, SAST tools can gain a deeper understanding of the code context. AI and LLMs analyze the codebase, usage patterns, and historical data to identify false positives more accurately.

These models can understand the intent behind the code and recognize patterns that indicate whether a finding is a true vulnerability or a false positive. For instance, they can differentiate between a hard-coded secret in production code and one used for testing purposes. Tools such as Corgea are able to identify these false positives. The contextual understanding provided by AI and LLMs significantly reduces the false positive rate.

Case Study: Corgea’s Approach

Corgea’s Advanced False Positive Detection is designed to address the pervasive issue of false positives in SAST findings by leveraging advanced static code analysis techniques and modern Large Language Models (LLMs). This solution integrates seamlessly with existing SAST tools to enhance their accuracy and efficiency, providing developers and security teams with reliable and actionable insights.

Several organizations have experienced significant improvements after implementing Corgea’s Advanced False Positive Detection. For instance, an enterprise company reported a 30% reduction in false positives, allowing their development team to focus more on innovation and less on triaging erroneous alerts. 

Key Features and Benefits

  • Contextual Understanding: Corgea’s solution uses AI to understand the context of the code, distinguishing between real vulnerabilities and false positives. This reduces the need for manual triage and investigation.

  • Clear Explanations: The tool provides detailed explanations for why a finding is identified as a false positive, making it easier for developers to understand and trust the results.

  • Accuracy and Speed: Corgea’s approach ensures high accuracy and fast processing, allowing teams to quickly identify and address genuine security issues.

  • Integration: Seamless integration with existing SAST tools and development environments ensures minimal disruption to workflows and maximizes efficiency.

Examples from Corgea’s False Positive Detection

Hard-Coded Cryptographic Keys

One common false positive identified by SAST tools is hard-coded cryptographic keys. While this can be a legitimate security concern, Corgea’s solution is able to recognize when these keys are used within a test suite rather than production code. For example, in a project using the JuiceShop application, Corgea detected a hard-coded JWT token within a test case. By understanding the context and recognizing the use of Angular’s testing module, Corgea correctly identified this as a false positive, saving developers time and reducing unnecessary alerts.

Cross-Site Scripting (XSS) in Django

Another example involves cross-site scripting (XSS) vulnerabilities flagged by SAST tools. In a project using Django, Corgea identified code that utilized Django’s `render_to_string` function. While this could potentially be a security risk, Corgea’s solution understood that Django’s template engine automatically escapes variables to prevent XSS. By recognizing this framework-specific nuance, Corgea accurately flagged the finding as a false positive, demonstrating its capability to differentiate between real and false threats effectively.

Measuring the Impact

To gauge the effectiveness of false positive detection solutions like Corgea’s, it is important to track key metrics. These include:

  • Reduction in False Positive Rate: Measure the decrease in false positives identified by the SAST tool after implementing Corgea’s solution.

  • Time Saved: Calculate the reduction in time spent by developers and security teams on triaging and investigating false positives.

  • Alert Fatigue Reduction: Track the decrease in the number of unnecessary alerts and its impact on developer productivity and morale.

  • Improvement in True Positive Identification: Measure the increase in the identification and resolution of genuine security vulnerabilities.

The long-term benefits of effective false positive detection are substantial. Development teams experience improved productivity and reduced frustration, leading to higher job satisfaction and better code quality. Security teams can focus on genuine threats, enhancing the overall security posture of the organization. Additionally, with fewer false positives, the organization can deploy updates and new features more quickly, maintaining a competitive edge in the market.


Recap of Key Points

False positives in SAST findings are a significant challenge for development and security teams, leading to wasted time, alert fatigue, and reduced efficiency. By adopting best practices such as proper configuration of SAST tools, incorporating contextual information, and leveraging advanced techniques like AI and LLMs, organizations can significantly reduce the incidence of false positives.

Reducing false positives is not just about improving tool accuracy; it’s about enhancing the overall workflow and collaboration between development and security teams. By focusing on both technological solutions and process improvements, organizations can create a more efficient and secure development environment.

Organizations should prioritize the adoption of best practices and advanced techniques for false positive detection. Investing in solutions like Corgea’s Advanced False Positive Detection can lead to substantial long-term benefits, including improved productivity, better security, and higher-quality software.

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