Knowledge What Is a Vulnerability Assessment? Explaining Its Necessity, Costs, and How to Choose a Service

A vulnerability assessment is the first step in corporate security measures, intended to identify and visualize latent weaknesses and flaws in computers, network devices, and software. Let’s start by correctly understanding its basic concept and purpose.

A vulnerability is a security weakness in operating systems, software, web applications, and more, caused by design errors or bugs in programs. If left unaddressed, such weaknesses can be exploited in cyberattacks.

For example, they may allow unauthorized access, enable the theft of personal information through illicit operations, or result in website defacement. Because new vulnerabilities can be discovered as long as systems are in operation, continuous countermeasures are required.

The primary purpose of a vulnerability assessment is to comprehensively identify where and what kinds of vulnerabilities exist in your operating systems and developed applications, thereby visualizing security risks. Through the assessment, you identify potential attack points and evaluate their severity.

This enables you to decide which vulnerabilities to address first and to plan and execute effective and efficient security measures.

In an era where most companies naturally provide web services, the importance of vulnerability assessments is growing. It is vital to recognize how neglecting assessments can lead to significant risks.

If vulnerabilities are discovered but left unremedied, malicious attackers may exploit them, causing various damages.

Typical risks include the leakage of confidential information such as customer data and credit card details. Information leaks lead not only to financial losses from compensations and regulatory fines but also directly to a loss of corporate reputation.

Other potential consequences include brand damage from website defacement and business interruption due to ransomware infections—situations that can threaten the business’s continuity itself.

Regularly conducting vulnerability assessments and promptly fixing identified issues is crucial not only to protect your information assets but also to maintain and enhance trust from customers and business partners.

Services handling personal data or e-commerce sites with payment functions especially require advanced security measures.

Conducting vulnerability assessments demonstrates a sincere corporate commitment to security, fostering customer confidence in using your services. In turn, this strengthens competitiveness.

A term often confused with vulnerability assessments is “penetration testing.” The two differ in purpose and methodology, and it’s important to use them appropriately depending on your situation.

The purpose of a vulnerability assessment is to comprehensively identify vulnerabilities lurking in a system.

In contrast, the purpose of a penetration test is to demonstrate whether it is possible to break into a system by exploiting vulnerabilities and, if so, what kind of damage could result.

You can think of a vulnerability assessment as a comprehensive health check and a penetration test as a targeted, in-depth examination for specific threats.

Vulnerability assessments investigate the entire system comprehensively based on checklists of known vulnerability patterns, combining automated tools and manual checks.

Penetration tests, on the other hand, are conducted by security experts who, adopting an attacker’s perspective, attempt intrusions using various techniques. They evaluate overall resilience, including human factors, based on realistic attack scenarios.

Neither approach is inherently superior; the key is to use them according to your goals. First, conduct regular vulnerability assessments to maintain overall security posture and obtain comprehensive visibility into vulnerabilities.

On top of that, run penetration tests for particularly critical systems or when you want to validate resilience against emerging threats from a more practical perspective.

Vulnerability assessments are categorized by the characteristics of the target system. Choose the appropriate assessment based on what you need to protect.

This targets browser-based web applications such as e-commerce sites, member portals, and business systems.

It detects web-specific vulnerabilities such as SQL injection and cross-site scripting (XSS), focusing on commonly targeted functions like authentication and personal data input forms.

This targets the underlying platform on which applications run—web servers, operating systems, databases, and network devices.

It checks for unnecessary open ports, outdated OS or middleware versions with known vulnerabilities, and configuration errors, evaluating the overall security strength of the system.

This targets native iOS and Android applications. It evaluates resilience against reverse engineering, whether sensitive data is stored in plaintext, whether communications with servers are properly encrypted, and other risks specific to mobile environments.

This targets configurations of cloud services such as AWS, Microsoft Azure, and Google Cloud Platform. While flexible, cloud environments are prone to configuration mistakes that can lead to major security incidents. It reviews for misconfigured access permissions, unintended data exposure, and whether the customer has fulfilled their configuration responsibilities under the shared responsibility model.

Vulnerability assessments are typically conducted via two approaches: automated tool-based testing and manual testing.

Each has strengths and weaknesses; combining them yields more accurate results.

This approach uses dedicated tools to automatically scan for vulnerabilities.

It is suitable for regular, broad checks thanks to its speed and coverage, and is relatively cost-effective. However, tools are largely limited to known vulnerability patterns and struggle to detect issues tied to complex specifications or design, such as business-logic flaws.

Also, determining whether a detected issue is truly risky (e.g., false positives) may require expert judgment.

Security experts manually probe for vulnerabilities while understanding the system’s specifications and business logic. This approach excels at uncovering higher-order and latent risks that tools often miss, such as access control weaknesses and issues that arise only through complex user flows.

The trade-offs are higher cost and longer timelines due to the expert skills and effort required.

Cost is one of the most important considerations when planning a vulnerability assessment.

While costs vary widely by target, scope, and method, it is helpful to understand general benchmarks.

The largest cost drivers are the size and complexity of the target.

For web application assessments, the number of dynamic pages/screens and functions typically forms the basis for estimation.

Small, static sites are relatively inexpensive, while large e-commerce sites with login, payment, and database integrations are costlier due to greater effort. For platform assessments, the number of target IP addresses is often the cost basis.

Many vendors offer vulnerability assessment services, making selection challenging.

Use the three points below to choose a service that aligns with your goals and requirements.

First clarify why you are conducting the assessment. The required depth and type differ depending on whether it’s the final pre-release check for a new service or a periodic check to maintain your security posture.

Then define the system scope in concrete terms (URLs, IP addresses, function lists, etc.). Clear requirements prevent misunderstandings with vendors and help you obtain accurate quotes.

For manual assessments in particular, assessor skill and experience greatly influence quality.

Check for relevant certifications (e.g., Registered Information Security Specialist in Japan) and whether the vendor has substantial experience in your industry.

It is also important that they routinely ingest and incorporate the latest attack techniques and vulnerability intelligence into their assessments.

Finding vulnerabilities is not the goal in itself. The most important part is to correctly understand each vulnerability and its risk and to translate that into concrete remediation.

Confirm that the vendor provides clear, accessible reports that allow non-experts to intuitively grasp severity and impact.

Robust aftercare—such as Q&A sessions, guidance on fixes, and responsive support—should also be key selection criteria.

What does the process look like when you engage a vendor? Below are four common steps.

The vendor first conducts a discovery session to learn the system’s architecture and functions. Prepare materials such as specifications and network diagrams to facilitate a smooth assessment.

Both parties confirm and agree on scope, schedule, and emergency contacts at this stage.

The vendor performs the vulnerability assessment according to the agreed schedule. Because high load may be placed on target systems during testing, assessments are often run outside business hours (e.g., nights or weekends). If a critical vulnerability is discovered, a preliminary alert may be issued promptly.

Upon completion, the vendor delivers a report detailing each discovered vulnerability, its severity, reproduction steps, and specific remediation methods. Typically, a debriefing session is held based on the report, and questions and answers help deepen understanding of the results.

Based on the report, your development team implements fixes for the identified vulnerabilities. After remediation, it is common to conduct a targeted reassessment limited to the previously flagged items to confirm that the countermeasures have been correctly applied. This ensures a reliable improvement in the overall security level.

This article comprehensively explained the basic concepts, necessity, types, costs, and selection criteria for vulnerability assessments. A vulnerability assessment is a fundamental and one of the most important security measures to protect your systems and business from cyberattacks. In particular, to comply with European cybersecurity regulations such as NIS2 and DORA, it is essential to make vulnerabilities visible and build a framework for continuous management.

By accurately understanding your organization’s situation and regularly conducting appropriate assessments aligned with your objectives, you can continue to provide safe and highly reliable services.

KDDI Cloud Inventory provides one-stop management of device security processes and a wide variety of cloud-based security features. Contact us to learn more.