Application vulnerability scanning can mean different things. There are at least three main types of such tools that can cover every layer of a complex infrastructure: application scanners, network scanners, and cloud security scanners.
Application security scanners (like DAST)
Application scanners focus on the layer where valuable and sensitive data is likely to be processed and stored. Checking applications for vulnerabilities is the domain of Dynamic Application Security Testing (DAST) tools, which can safely simulate real-world attacks to detect weaknesses such as SQL injection, cross-site scripting (XSS), and security misconfigurations. By proactively testing websites and APIs, such solutions help minimize risks in the attack surface. Integrated into the software development lifecycle, they can detect flaws during runtime before they reach production, and speed up remediation.
When it comes to scanning applications, there can be confusion between source code analysis and runtime scanning. Static Application Security Testing (SAST) tools are used during development to inspect source code, but they do not work with a running application.
Network vulnerability scanners
Many IT professionals are referring to network scanners when they talk about a “vulnerability scanner”. In the days before cloud environments, when corporate servers and workstations ran software within the local network infrastructure, such attacks were a primary route for malicious hackers. While network vulnerability scanning is still important for things like identifying open ports and ensuring proper firewall and network configurations, in cloud deployments, much of this is handled by cloud services, making a network vulnerability scanner less important for the typical cloud-oriented organization.
Cloud security scanners
To some extent, cloud infrastructures have taken over the traditional role of network ones. Cloud security scanners focus on detecting vulnerabilities specific to cloud environments, including misconfigurations and insecure APIs. They are critical for ensuring compliance and protecting against data leaks resulting from attacks on cloud services. But, as with network scanning, most cloud providers include at least a basic level of cloud security scanning in their offerings. For many organizations, this makes a dedicated cloud security scanner a lower priority tool.
Why are application vulnerability scanners important?
Websites and APIs are the external attack surface and are subject to frequent changes that increase the risk of security gaps making it into production. Therefore, application vulnerability scanners are essential tools for identifying vulnerabilities in web resources. By safely simulating attacker actions, these solutions (like DAST) can identify many common types of vulnerabilities, allowing teams to fix security flaws before they can be exploited by attackers and lead to data leaks or something worse.
Some vulnerabilities can be found by different types of tools, which leads to the misconception that testing a website with a network scanner is the same as with DAST. In fact, other types of tools may only detect a fraction of the application security issues compared to a purpose-built solution. For example, a network scanner might scan a website and flag issues with a vulnerable web server version or insecure header settings, but that is only a small percentage of the attack surface and potential security flaws.
A high-quality DAST tool will find all the issues reported by a network scanner, as well as perform a wide range of additional passive and active checks. This allows it to find not only misconfigurations and Common Vulnerabilities and Exposures (CVEs), but also security weaknesses such as cross-site scripting, SQL injections, cross-site request forgery (CSRF), and more. Advanced application scanners have their own vulnerability databases and can perform automated authentication and API testing. Leading DAST solutions can also be integrated into the development lifecycle to help teams identify and remediate potential vulnerabilities before they go into production.
Common challenges in application vulnerability scanning
Scan coverage and accuracy
Maximizing coverage is probably the biggest technical challenge for automated vulnerability scanning. Modern business applications and APIs are often built and deployed in a continuous development pipeline that encompasses not only the company’s own code, but also open-source components, external dependencies, and framework code. Applications are also typically highly dynamic and often require authentication to prevent unauthorized access, thus legacy scanners that cannot perform such scans become powerless.
False positives management
False positives are a problem for any automated testing without advanced enterprise-grade features like Proof-based scanning in Invicti (formerly Netsparker). Legacy vulnerability scanners were originally designed to assist in manual penetration testing, and therefore tend to generate a certain number of false positives not to miss potential vulnerabilities.
Integration with the development life cycle
Performing an external vulnerability assessment from time to time is not enough. It cannot keep up with the pace of application development. Integrating SAST tools into the pipeline is now standard engineering practice. Similarly, it is important to implement an application scanner (DAST) into the software development life cycle (SDLC). If the chosen tool produces high-quality reports, it brings additional benefits. Automation and integration with popular issue tracking and CI/CD systems become possible. This allows teams to launch dynamic security testing as early as possible. It also helps reduce the time needed to resolve issues found in production.
Application scanners in a cybersecurity program
DAST tools allow specialists to test real attack surface (when used for external scanning) and improve the security of development through in-pipeline checks. As such, they perform important tasks in overall cybersecurity strategy and program:
- Identifying and remediating weaknesses. The primary function of application scanners is obviously to find vulnerabilities. To be most effective, scans should ideally run automatically on a schedule, with the results sent to issue tracking systems.
- Accurate results. Advanced application scanners, like Invicti, can provide confirmed reports of vulnerabilities found. These reports include information about severity and potential impact levels. This helps security engineers prioritize remediation. It also helps streamline security processes.
- Improving application security in the long term. Reactive remediation based on scan results is the most obvious aspect of fixing vulnerabilities. However, preventing future weaknesses is even more valuable. An accurate application scanner should provide developers with complete technical information. It should also offer remediation guidance and retesting capabilities. These features can help teams avoid making similar mistakes in the future.
- Ensuring compliance with standards. DAST tool can be invaluable for compliance with requirements such as PCI DSS, ISO 27001, or internal standards, as many of these explicitly specify vulnerability scanning as a mandatory requirement.
Conclusion: application vulnerability scanning is proactive defense
When combined with network and cloud security scanners, DAST tools provide a complete view of the risk level of applications. They enable a proactive approach to address vulnerabilities before they can be exploited by attackers, ensuring a more resilient IT environment.
