Write chapter 3 of report "Advantages and disadvantages of vulnerability scanners" using technical information from text below. Chapter value is 500-600 words. Use only information related with chapter topic:

Chapter 3: Disadvantages of Vulnerability Scanners
3.1. Potential for False Positives and Negatives
3.2. Scope Limitations and Contextual Challenges
3.3. Risks and Security Implications

A vulnerability scanner is a computer program designed to assess computers, networks or applications for known weaknesses. These scanners are used to discover the weaknesses of a given system. They are utilized in the identification and detection of vulnerabilities arising from mis-configurations or flawed programming within a network-based asset such as a firewall, router, web server, application server, etc. Modern vulnerability scanners allow for both authenticated and unauthenticated scans. Modern scanners are typically available as SaaS (Software as a Service); provided over the internet and delivered as a web application. The modern vulnerability scanner often has the ability to customize vulnerability reports as well as the installed software, open ports, certificates and other host information that can be queried as part of its workflow.

Authenticated scans allow for the scanner to directly access network based assets using remote administrative protocols such as secure shell (SSH) or remote desktop protocol (RDP) and authenticate using provided system credentials. This allows the vulnerability scanner to access low-level data, such as specific services and configuration details of the host operating system. It's then able to provide detailed and accurate information about the operating system and installed software, including configuration issues and missing security patches.[1]
Unauthenticated scans is a method that can result in a high number of false positives and is unable to provide detailed information about the assets operating system and installed software. This method is typically used by threat actors or security analyst trying determine the security posture of externally accessible assets.[1]
Vulnerability scanners should be able to detect the risks in open-source dependencies. However, since developers will usually re-bundle the OSS, the same code will appear in different dependencies, which will then impact the performance and ability of scanners to detect the vulnerable OSS.[2]

The CIS Critical Security Controls for Effective Cyber Defense designates continuous vulnerability scanning as a critical control for effective cyber defense.

Vulnerability scanners are software or hardware tools used to diagnose and monitor network computers, allowing you to scan networks, computers and applications to detect possible security problems, assess and eliminate vulnerabilities.

Vulnerability scanners allow you to check various applications in your system for holes that could be exploited by attackers. Low-level tools, such as a port scanner, can also be used to identify and analyze possible applications and protocols running on the system.

1 Types of vulnerability scanners
2 Software
3 See also
4 Notes
5 Literature
Types of Vulnerability Scanners
The work of a vulnerability scanner can be divided into 4 steps:

Typically, the scanner first detects active IP addresses, open ports, running operating system and applications.
A security report is generated (optional step).
Attempting to determine the level of possible interference with the operating system or applications (may result in a crash).
At the final stage, the scanner can exploit the vulnerability, causing the operating system or application to crash.
Scanners can be malicious or friendly. The latter usually stop at step 2 or 3, but never get to step 4.

Among the vulnerability scanners we can highlight:

Port scanner
Scanners examining the topology of a computer network
Scanners that examine network service vulnerabilities
Network worms
CGI scanners ("friendly" - help find vulnerable scripts)
Software
Top ten vulnerability scanners according to insecure.org (2006)[1]

Nessus: Vulnerability Assessment for UNIX
GFI LANguard: Commercial network vulnerability scanner for Windows
Retina: A commercial vulnerability assessment scanner
Core Impact: Automated intrusion testing product
ISS Internet Scanner: Application Level Vulnerability Assessment
X-scan: Network vulnerability scanner
Sara: Security Auditor's Research Assistant
QualysGuard: Vulnerability scanner (web service)
SAINT: Security Administrator's Integrated Network Tool
MBSA: Microsoft Baseline Security Analyzer
Other well-known vulnerability scanners:

XSpider
OpenVAS
ERPScan SAP security scanner
SurfPatrol
COMPLAUD
RedCheck

Web Application Vulnerability Scanners are automated tools that scan web applications, normally from the outside, to look for security vulnerabilities such as Cross-site scripting, SQL Injection, Command Injection, Path Traversal and insecure server configuration. This category of tools is frequently referred to as Dynamic Application Security Testing (DAST) Tools. A large number of both commercial and open source tools of this type are available and all of these tools have their own strengths and weaknesses. If you are interested in the effectiveness of DAST tools, check out the OWASP Benchmark project, which is scientifically measuring the effectiveness of all types of vulnerability detection tools, including DAST.

OWASP is aware of the Web Application Vulnerability Scanner Evaluation Project (WAVSEP). WAVSEP is completely unrelated to OWASP and we do not endorse its results, nor any of the DAST tools it evaluates. However, the results provided by WAVSEP may be helpful to someone interested in researching or selecting free and/or commercial DAST tools for their projects. This project has far more detail on DAST tools and their features than this OWASP DAST page.

Vulnerability scanner - a software or hardware product for searching for threats in infrastructure
companies. The scanner is used to detect gaps in network protection, operating systems, databases,
applications, etc. The main task is to assess information security, identify vulnerabilities and provide
reports.
Using a scanner, an administrator can find “holes” that hackers use to obtain
unauthorized access (NAA) to confidential data on the company network. A vulnerability scanner can
monitor running processes, services and scan used ports.

Vulnerability scanner - a software or hardware product for searching for threats in infrastructure
companies. The scanner is used to detect gaps in network protection, operating systems, databases,
applications, etc. The main task is to assess information security, identify vulnerabilities and provide
reports.
Using a scanner, an administrator can find “holes” that hackers use to obtain
unauthorized access (NAA) to confidential data on the company network. A vulnerability scanner can
monitor running processes, services and scan used ports.
Main functions
The software product has the following functions:
How the scanner works

searches for various types of network vulnerabilities and analyzes them in real time;
checks network resources, OS, connected devices, ports;
analyzes all active processes and the behavior of running applications;
creates reports that indicate the type of vulnerability.
Probing. An effective but slow way to find and analyze vulnerabilities. Its essence is that
the solution initiates virtual attacks and monitors the network infrastructure to search for vulnerable points. By
At the end of the process, the administrator is provided with a detailed report indicating the problems found and
recommendations for their deactivation.
Scanning. In this mode, the scanner operates at the maximum possible speed, but analyzes the network
infrastructure at the surface level. That is, it detects obvious vulnerabilities and analyzes the overall
infrastructure security. Compared to the previous method, this method only warns about
found administrator problems, but nothing more.

What actions does a vulnerability scanner perform?
Scanners can be "friendly" or "aggressive". The first type simply collects information and does not model
attack. The second exploits the vulnerability to cause software to crash.
Collects information from the entire infrastructure: active processes, running applications, running ports and
devices, services, etc.
Search for potential vulnerabilities using different methods.
Uses special methods of simulating attacks to find possible vulnerabilities (the function is not available in every
scanner).
Generates a detailed report with information about found vulnerabilities.

Vulnerability scanners are the front line of vulnerability management. They are essential for identifying vulnerabilities that could be used by bad actors to compromise systems and data.

In the old days of monolithic on-premise applications, vulnerability scanners were deployed primarily in the production environment as infrastructure watchdogs that alerted to runtime threats. This paradigm became obsolete with the emergence of cloud-native applications that leverage the powerful scalability and agility of modern cloud-based infrastructure. As applications and the tools to secure them become more complex, solutions like ASPM are emerging to bring together the different data streams and enable risk based prioritization and remediation.

Today’s highly automated CI/CD pipelines cannot tolerate security testing bottlenecks. The detection and remediation of vulnerabilities must keep up with the frenetic pace of mature DevOps practices.

Yet another challenge to legacy security paradigms is the highly distributed architecture of cloud-native applications, based on dynamic components such as open-source libraries, serverless functions, infrastructure as code (IaC), and containers. In short, cloud-native applications require a new cloud-native application security paradigm: ensuring that vulnerabilities are detected and fixed during development with a holistic approach that makes security an integral part of the software development life cycle (SDLC).

In this article, we describe the different kinds of vulnerability scanners that, together, provide cloud-native security coverage for websites, web applications, networks, open-source code, WordPress content, and containers (such as our Docker scanner).

3 Most common types of scanners
Network vulnerability scanners

Web application vulnerability scanners

Open-source vulnerability scanners

1. Network Vulnerability Scanners
Network vulnerability scanners monitor web servers, their operating systems, their daemons and any other services open to the internet such as database services.

Network vulnerability scanners work against a database of known vulnerabilities. Many of these databases rely on the Common Vulnerabilities and Exposures (CVE) Program’s free and comprehensive catalog of known software and firmware vulnerabilities. Each standardized record is comprised of a unique CVE identifier, a brief description, and at least one public reference.

Going one step further, the Common Vulnerability Scoring System (CVSS) enriches the CVE List with a numerical score of the vulnerability’s technical severity. However, the best network vulnerability scanning results are achieved with proprietary vulnerability databases that continuously aggregate and analyze information from a wide range of sources. A good example is the Snyk Vulnerability Database, which is tightly integrated with vulnerability databases, threat intelligence systems, community sources, and academia. Hand-curated by a dedicated security team, Snyk’s Vulnerability Database optimizes network vulnerability scanners so that they can deliver accurate and actionable insights.

This heightened ability to extract maximal insights into network vulnerabilities is important for operational reasons as well. The not-for-profit Center for Internet Security (CIS) maintains a set of CIS Controls to help organizations implement cybersecurity best practices. One of the basic controls is that vulnerability management—including scanning—be continuous. However, because network vulnerability scans can cause congestion, scans are typically carried out only once a week. It is therefore critical that these scans be carried out against an enriched database that provides comprehensive coverage into known and unknown vulnerabilities.

2. Web Application/Website Vulnerability Scanners
Web vulnerability scanners scan application/website code to find vulnerabilities that compromise the application/website itself or its back-end services. They are an essential component of application security testing.

These scanners work against a known list of common exploits as maintained by OWASP and others. These exploits use various injection and evasion techniques to “hijack” web applications and websites in order to exfiltrate data, to trick users or systems into providing sensitive information, or to disrupt application performance. Some of the better known exploits are SQL injection, cross-site scripting (XSS), man-in-the-middle (MITM) attack, and malicious code.

When it comes to web applications, the only effective vulnerability management strategy is to adopt a shift-left DevSecOps approach and deploy scanners throughout a secure SDLC (software development life cycle). This battery of scanners includes static application security tools (SAST) that automatically scan uncompiled code for vulnerabilities, and dynamic application security tools (DAST) that automatically scan compiled code across all environments from testing to production.

Another important tool is penetration testing, which essentially simulates hackers in order to discover if a web application or website is vulnerable to malicious exploits. There are even website vulnerability scanner online services that conduct third-party penetration testing.

The Snyk SAST solution has been designed from the ground up to overcome the challenges that developers and ethical hackers face with legacy SAST tools, such as taking hours or even days to complete a scan, high false positive rates, and requiring deep security knowledge to remedy issues. With Snyk Code, SAST becomes a seamless part of the development process, providing developers and security teams with real-time and accurate visibility into code vulnerabilities and how to fix them.

3. Open-Source Vulnerability Scanners
Open-source vulnerability scanners are software composition analysis (SCA) tools that scan applications to discover all open-source frameworks and libraries—including all direct and indirect dependencies—and identify vulnerabilities. Some open-source vulnerability scanners also help developers in the non-trivial task of precisely locating the vulnerable code in the codebase.

Seeing that using components with known vulnerabilities is one of the OWASP Top 10 vulnerabilities, organizations must ensure that they are using a state-of-the-art open-source vulnerability scanner. The advantages of the Snyk open-source vulnerability scanner include:

Early detection of open-source code vulnerabilities, before web applications or websites have been compromised.

Prompt discovery of all instances affected by a detected open-source code vulnerability, so that attackers can be locked out and issues can be remediated faster.

Clear documentation of all open-source frameworks and libraries used in applications.

Ensures compliance with open-source license requirements.

How to Evaluate a Vulnerability Scanner
The good news is that there are many commercial and free vulnerability scanners available on the market today. However the flip side to that is that having so many options can make it difficult to evaluate which scanner stack is optimal for your requirements.

The first step is to learn more about the vulnerability scanners. OWASP maintains a comprehensive listing of commercial and free vulnerability scanners, although they refrain from ranking them. Other trusted influencers provide “Top xx” lists of recommended scanners.

Once you have created a short list of vulnerability scanners, you can try them out. Even the commercial vulnerability scanners offer free trials so that you can kick the tires before making a final decision. Given the diverse set of vulnerability scanners that you will have to deploy in order to achieve end-to-end coverage across all your environments, you may also want to consider a vulnerability management platform that knows how to integrate with all your scanners and correlate their outputs into a single source of vulnerability management truth.

Why is vulnerability scanning important?

Vulnerability scanning is the essential front end of any vulnerability management program. Today, vulnerability management is no longer a nice-to-have but rather a business-critical requirement for any organization running web applications or interactive websites. These kinds of public-facing assets are common attack vectors for malicious actors seeking unauthorized access to systems and data.

What are the types of vulnerability scans?

Vulnerability scans differ depending on how they are deployed and what they are scanning. Scans can be internal or external, credentialed or non-credentialed, and comprehensive or device-specific. The optimal operating modality depends on what is being scanned: networks, web applications throughout the secure software development life cycle, or open-source codes and libraries.