What is Vulnerability Scanning? Understand How It Works (2023)

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Vulnerability scanning is the process of scanning IT networks and systems to identify security vulnerabilities in hardware and software.

As enterprise IT environments have grown more complex, the ways hackers can attack them have grown too. The edge, cloud computing, Internet of Things (IoT) devices, and more have led to a much bigger attack surface and have required new vulnerability scanning approaches and tools.

Cybersecurity vendors and developers have responded to these growing challenges by evolving vulnerability scanning tools and integrating these solutions as part of an integral, holistic vulnerability management framework.

See the Best Vulnerability Scanning Tools

Table of Contents

How Does Vulnerability Scanning Work?

Vulnerability scanning tools, or vulnerability scanners, do much of the work by scanning IT systems and networksto identify vulnerabilities in devices and software and flag those that need attention.

But that’s just one step in the process. There are six phases in the vulnerability assessment and management process, and they all work together to ensure optimal security.

Phase one: Asset inventory

The first phase of vulnerability management is to create a comprehensive asset inventory across the entire organization. Because a vulnerability scan will only reveal a particular moment of your operations frozen in time, security programs and vulnerability scanning tools must be scheduled to run automated, periodic scans.

Also read: Top IT Asset Management (ITAM) Tools for Security

Phase two: Setting priorities

The next step is critical for vulnerability scanning tools to be effective; assets must be prioritized based on business-critical degrees. This means that, by now, you must know what to scan, when to scan it, and what are the most important assets in the scan. This phase streamlines security decision-making and helps teams respond with precision without wasting time and resources.

Phase three: Assessment

The third phase of the vulnerability management program is assessment. This is where security tools come into play. Once vulnerability scanning solutions are configured with the “where, when, and what’s a priority,” the scans are executed. This allows you to determine which risks to eliminate first based on various factors, including their criticality and vulnerability threat levels, as well as classification.

Vulnerability scans use the asset or data inventory and scan the attack surface in search of flaws, coding bugs and errors, anomalies, and default or misconfigured configurations. Then, they identify potential paths attackers can exploit.

Phase four: Reporting

The vulnerability scanning and assessment cycle is completed with the reporting phases, in which vulnerability scanning and other security tools issue reports. Findings are used to get a clear idea of the risks, factors, and threats levels.

Phase Five: Remediation

During this phase the reports are used to patch flaws. Some vulnerabilities, like outdated software or outdated operating systems, can be easily solved with updates. Other fixes require advanced technical knowledge.

For example, cross-site scripting attacks, SQL injection vulnerabilities, and unencrypted channels require an experienced professional. Professional vulnerability scanning vendors usually offer a final report with all weaknesses discovered and pair each flaw with a recommended action.

Phase six: Verification and monitoring

The vulnerability scanning process ends with a final phase and then a restart of the entire process. The final phase sets new schedules for vulnerability scanning to verify flaws corrected and monitors the networks and systems.

Also read:

Vulnerability Scanning vs. Penetration Testing

The main difference between vulnerability scanning and penetration testing is that the first is fully automated, while the second includes the manual work of a penetration tester that will exhaustively try to exploit weaknesses in systems. Penetration testers simulate attacks; they try to get in the mindset of a cyber criminal and use their techniques to find weaknesses and report the consequences that such a breach could have.

While intrusive vulnerability scanning can also exploit vulnerabilities, it does so automatically. The real purpose of a vulnerability scan is to give security teams a big picture look at critical assets, system and network flaws and security.

Despite their differences, both vulnerability scans and penetration tests are part of the wider vulnerability management framework or process. They are two different tools, each essential in their own way and critical for chief information security officers (CISOs) to keep their infrastructure safe.

While pentesting is part of a broader vulnerability management program, the two have one other essential difference: Vulnerability management is looking at IT and business systems as a whole, while pentesters are typically trying to breach an organization from outside the network (see Penetration Testing vs. Vulnerability Testing: An Important Difference).

Why Is Vulnerability Scanning Necessary?

Just as security teams run vulnerability scanning tools, cyber criminals do the same. They are constantly searching for flaws and weak entry points into a system. Additionally, a vulnerability scan reveals only your network and systems at a particular time. Therefore, scheduled and automated vulnerability scans are necessary to understand the security posture of the system and its flaws throughout different periods.

Vulnerability scanning also allows companies to take a proactive offensive approach to defensive security. They seek to stay one step ahead of cyberattacks and to maintain strong systems. Scans will enable you to close gaps before they become incidents.

Given the high cost of cyberattacks, vulnerability scans act as a cost-effective way to stay proactive in protecting your network. The consequences of breaches can be devastating, from data exfiltration to leaks, ransomware extortion, legal suits, fines, loss of reputation, and even shutdown of operations. Along with other tools, vulnerability scans are essential to protect against these consequences.

Types of Vulnerability Scanning

Security teams can configure vulnerability scans to execute different tests. It’s important to note that while top vendors offer modern vulnerability scanning tools that can be tuned, other solutions are niche or outdated. It’s essential to understand each type of scan and what your organization needs to make sure you get the right solution.

Bug bounty programs

Bug bounty programs use a community-driven approach to vulnerability scanning. These programs incentivize freelance hackers to find bugs on public-facing systems by offering rewards. Bug bounty programs have become increasingly common and are used by top technology companies. In these programs, organizations can have their system continuously tested throughout their life cycle.

Internal scans

These scans are done from inside the network using techniques such as privilege escalation. Internal scans are especially useful for mapping workforce permissions and finding vulnerabilities to an inside attack.

Also read:

External scans

These will scan all assets online, including employee login pages, remote access ports, or company websites. These scans help organizations understand their online weaknesses and how they can be used to gain access to their network.

App-based scans

These scans are used when companies need to understand the flaws of specific endpoints — for example, a web-facing server, IoT devices or wireless networks. Assets scanned are usually linked to the company’s critical operations assets to prevent attacks that can cause downtime.

Continuous scans

These are automated scheduled scans that usually run every quarter. Industry experts recommend that vulnerability scans be run at least once every three months. These scans can be configured as comprehensive or limited, external or internal, or other types.

Breach and attack simulation (BAS) tools offer a more automated approach to vulnerability scanning and penetration testing.

Intrusive and non-intrusive scans

Non-intrusive scans do not engage in vulnerability exploitation, and the report is based on the probability of a breach happening. On the other hand, intrusive scans will attempt to exploit vulnerabilities if discovered. An intrusive scan will make the stakes clearer but could also disrupt operations.

Limited or comprehensive scans

Vulnerability scans can be limited to a certain set of devices, systems, and networks or be comprehensive and include all components.

Authenticated and unauthenticated scans

Vulnerability tools can run unauthenticated scans where only the open services available on the network are evaluated. On the other hand, authenticated scans access resources and assets that can only be scanned with privileged access and thus test higher-value targets.

Complementary Security Measures

Vulnerability scanning is augmented by different tools within the vulnerability management program. These tools include asset discovery and inventory management solutions, which help IT teams keep track of all devices, software, servers, and more across the company’s digital environment.

Other tools like patch management solutions ensure that systems and apps are up to date with the latest security patches. These automatically check for updates and notify teams when an update is required or new updates become available. They can run on entire networks.

Misconfiguration is one of the most common vulnerabilities leveraged by hackers. Security configuration management (SCM) software ensures devices and their security settings are properly configured. Some SCM tools can scan devices and networks for vulnerabilities, track remediation actions, and generate reports on security policy compliance.

While vulnerability scans only provide a view of the system frozen in time, security information and event management (SIEM) software can provide real-time insight into security information and events by analyzing log data from a wide variety of sources. They are designed to let security teams know what’s happening across their IT infrastructure, including network traffic, devices trying to connect to internal systems, user activity, and more.

Penetration testing is another tool used in vulnerability management. By simulating attacks in realistic ways, testers can identify weak spots in systems that real-world attackers could exploit. Finally, threat protection software allows organizations to track, monitor, analyze, and prioritize potential threats by collecting data from various sources.

Vulnerability Scanning Software and Tools

There are many vendors offering different solutions for vulnerability scanning. However, most require IT professionals to configure them and make sure the scans are done correctly. Additionally, security professionals also need to interpret the reports these tools generate.

To meet the demands of digital transformation, many traditional vulnerability scanning tools have been updated to prioritize flaws based on critical business levels, to scan new surfaces like IoT devices, and to detect human-element security weaknesses to phishing and other employee-directed attacks.

Here are some of the top vulnerability scanners; see our lists of open source and commercial vulnerability scanners for more options.

Top vulnerability scanning tools

  • OpenVAS: Runs multiple scanning techniques, including internal and external scans. The platform has a dedicated community of testers and uses its programming language for multiplatform flexibility.
  • Tenable: Offers comprehensive vulnerability management solutions specializing in continuous monitoring, not just on single vulnerability scans. It also provides compliance reports, risk assessments, and threat monitoring.
  • Network Mapper: Also known as Nmap, this open-source vulnerability scanner can identify vulnerabilities in protocol, view running services, and port scan different addresses.
  • Rapid7: Provides different tools for vulnerability management, including SIEM and vulnerability scans. The platform offers managed security services, product consultations, and certification programs.

Bottom Line: Vulnerability Scanning

Vulnerability scanning is a critical cybersecurity practice that every organization needs to be doing to limit potential entry points for hackers.

Vulnerability scanning tools have come a long way, adapting to the challenges of an increasingly dangerous security landscape. Today, vulnerability scans are configurable and can set priorities and give new insights relevant to the expanded digital attack surface. They’re an essential cornerstone of a vulnerability management program.

Read next: Vulnerability Management as a Service (VMaaS): Ultimate Guide

This updates an April 5, 2019 article by Paul Rubens

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