Penetration Testing vs Vulnerability Scanning: Everything You Need to Know

It’s not enough to establish a robust security environment — it’s also important to regularly check it for potential vulnerabilities. To learn how susceptible a system is to various vulnerabilities and threats, organizations typically use penetration (pen) testing and/or vulnerability assessment. And while it’s easy to confuse the terms, every organization needs to clearly differentiate between the two. 

In this article, we compare penetration test vs vulnerability scan, list the core differences between them, and explain why they are critical for your cybersecurity. If you have not yet planned your next cybersecurity assessment, now might be a good time to plan one!

What is pen testing?

Penetration testing is a set of ethical hacking methods aimed at evaluating the security of a system. In other words, this process implies the use of hacking techniques in order to «crack» the system, assess what vulnerabilities are present, and how critical they are.

Note that the main difference between hacking and ethical hacking is that the latter is not performed with the aim to steal sensitive data or get access to it. Its main goal is to test the system and all involved parties are aware of the process and of the deployed methods.

Since penetration testing is pre-approved, it’s logical to assume that there are certain frameworks and guidelines to follow when planning a pen test. The most well-known are:

• OWASP penetration testing guidelines;
• Open Source Security Testing Methodology Manual (OSSTMM for short);
• Cybersecurity framework by The National Institute of Standards and Technology (NIST);
• Penetration Testing Execution Standard known as PTES.

If we take OWASP guidelines, for example, the documents provide a detailed explanation of pen test requirements, reporting, and all involved aspects. By following such standards, organizations can make sure that pen testing will be secure and will not harm it in any way.

Penetration testing types

Before moving on further, it is important to differentiate between different pen testing types. 
You can categorize the test types depending on your goal:

• External tests: the attack is aimed at assets that are visible to people outside the organization (i.e. websites, apps). In this way, you can test the efficiency of possible external attacks.
• Internal tests: are performed in a scenario when an attacker has access to internal assets and resources.
• Blind tests: in this case, the attacker can obtain publicly available information but has no knowledge of internal assets.

Now let’s move on to the seven stages of a penetration test and to the processes that each stage contains.

The main steps of pen testing 

Though every penetration test will be different for every organization, there are certain guidelines to follow and certain steps to take. Below, we list the core stages of pen testing that can serve as a base to plan your strategy. Note that we used the OWASP recommendations as a base though some sources list six steps only.

1. Pre-engagement interactions: preparation for the upcoming pen testing and set up of all needed processes.
2. Intelligence gathering: in other words, collection of relevant information (i.e. about the system), as well as secure approval from the organization’s management.
3. Threat modeling: the process of modeling future threats and the ways they will be used on a target.
4. Vulnerability analysis: involves vulnerability assessment (more on it below) and the main aim is to understand whether the target is susceptible to known or expected threats.
5. Exploitation: the process of performing an attack on a system.
6. Post exploitation: involves all processes related to system recovery.
7. Reporting: a very important step since every pen testing requires detailed reporting once it’s finished. You can find more information on reporting in the OWASP documentation.

Now we can move on to vulnerability assessment. Is it part of pen testing or is it an independent process? Are these two processes the same? Let’s make the penetration test vs vulnerability scan clear.

What is a vulnerability assessment?

While pen testing is used to test the system’s endurance against attacks, vulnerability assessment is more of a scanning procedure. VA is used to check the system against the database of known vulnerabilities and see whether they are present in the system. As well, VA is used to categorize the vulnerabilities and mark them as critical or not.

The main goal of vulnerability assessment is to identify existing vulnerabilities and analyze how to deal with them in the most effective manner. In this way, the VA process helps companies strengthen their cybersecurity by understanding its current state and knowing what needs to be improved.

Vulnerability assessment is typically performed with the help of automated scanning tools — more on them below. As for now, let’s look at the two main types of VA:

• As part of the pen testing: in this case, vulnerability assessment is included in step 4 of penetration testing and helps identify present vulnerabilities before executing the attack.
• As an independent process: in this case, VA serves as a regular security check and keeps organizations updated on their security status.

Depending on the tested target, there is another categorization of vulnerability assessment:

• Network-based: VA tests the organization’s network and analyzes its security; 
• Host-based: analyzes workstations, servers, or other hosts;
• Wireless network scanning: analyzes the organization’s Wi-Fi network;
• Applications: scans web or network applications;
• Database: checks databases for weak areas.

Vulnerability assessment scanning tools

As mentioned above, vulnerability assessment is usually performed by using automated scanning tools. Luckily, there is a variety of them in the market. But as with any other tool related to cybersecurity, you need to be extra cautious in order to choose a reliable one. And once again, you can rely on OWASP since there is a list of OWASP-recommended vulnerability scan tools. 

You can find the full list here and meanwhile, let’s briefly overview it. The list contains tools from A to Z and includes both free and commercial solutions. As well, it states the platforms on which each tool runs (Windows, macOS, Linux, SaaS) so you can find the one for your exact platform.  

Difference between a penetration test and vulnerability assessment

When talking about penetration test vs vulnerability scan, these two terms are often used in conjunction. However, they can be used separately as well — everything will depend on your business goal.

In the table below, we will look at the main features of each security testing type and at the differences between them. By knowing these peculiarities, it will be easier for you to adjust your testing strategy correspondingly.

In this table, we’ve summarized the core features to compare. However, we can also look at penetration testing vs vulnerability scanning in more detail.

Speed

In terms of execution speed, vulnerability assessment is much faster and may take a few minutes only (or a few hours at most). Pen testing, on the contrary, is a much more complex process that involves several stages. Thus, it may take a few weeks to fully complete penetration testing and assemble a detailed report.

Depth of analysis and performance

We’ve already mentioned it in the table but let’s repeat once again. Vulnerability assessment has certain limitations and may not detect certain issues, such as business logic errors. As well, the VA process is not as deep as penetration testing and may leave tiny security flaws unnoticed.

Penetration testing, on the other hand, provides a holistic view of the state of the system and offers deep insights into existing flaws and their severity. And since it implies manual testing, pen testing becomes highly efficient against difficult vulnerabilities.

Risk analysis

As you can guess from the name, risk analysis is the process of identifying and assessing risks. By risks we mean the factors that may harm the organization and negatively impact its security. And while both vulnerability assessment and penetration testing are effective in analyzing risks, their scope of work slightly differs.

Vulnerability assessment provides you with CVSS scores for each vulnerability. CVSS stands for the Common Vulnerability Scoring System and is used to measure the severity of each detected vulnerability. In this way, VA kind of tags vulnerabilities but that’s all the information it provides in regards to risk assessment.

With penetration testing, things are much more interesting. In addition to detecting vulnerabilities, pen testing also provides you with information on how much access one can get via certain vulnerabilities, how quickly and how far threat actors can escalate the privileges, and how much of a loss the exploitation of a certain vulnerability can bring. In simple words, pen testing not only tells you what’s there in terms of vulnerabilities but also how bad it is.

So, which security testing method do you really need?

In a perfect world, we’d highly recommend you perform both regular VA checks as well as annual penetration testing. However, we also understand that there are many factors impacting one’s cybersecurity strategy, such as time or availability of resources.

So how do you know which testing method you need right now (if you need any at all)? While it’s preferable to consult a knowledgeable cybersecurity expert, we’ve also assembled a small list of questions that might help you:

• Does your organization process sensitive data on a regular basis, and how much sensitive data does your organization process?
• How critical will it be for you and your clients if your system is under a cyber attack?
• Do you have all the needed resources to perform proper security checks in accordance with approved guidelines?
• Will you be able to invest a certain amount of time into educating your employees on cyber security?

The thing is, the more sensitive data your organization processes and stores, the more important it is to regularly perform security checks, including in-depth ones. In general, it is recommended that organizations of any size and within any domain implement certain security procedures — see our article on CIS controls, for example. But for certain organizations, the cost of a small mistake is much higher than for others and you need to determine in what category your company falls. After that, you will be able to make the right choice between penetration test vs vulnerability scan.