Vulnerability testing vs. Penetration testing

With the wide range of growing cybersecurity threats creating risks for businesses today, organizations must be proactive in their approach to cybersecurity. The days of reactive security and waiting for cybersecurity incidents are over. The sheer scope, scale, and damage path of today’s cybersecurity incidents are far too great to react passively. Instead, businesses must find the vulnerabilities and “cracks in their armor” before the bad guys. Two valuable tools in the arsenal for organizations today are the vulnerability scan and the penetration test. What are these, and how are they different?

Different tools for different purposes

Businesses today are facing increasing challenges with cybersecurity and compliance. With major cyberattacks making headlines and causing extensive disruption to even critical infrastructure services, companies must take ownership of securing their business-critical resources. However, there are two resources businesses can avail themselves of to provide valuable results in bolstering security. These are:

  • Vulnerability scans
  • Penetration tests

Let’s detail what value businesses gain from both the vulnerability scan and penetration tests. Are both needed? How do they compare?

Vulnerability scans

What is a vulnerability scan, and what does it do for your business? A vulnerability scan scans your business-critical environment for known vulnerabilities in software, hardware, firmware, drivers, and other exploitable components.

Are vulnerabilities a problem in most environments? Yes, they are. In addition to compromised credentials, attackers commonly use exploited vulnerabilities to gain entry into networks. On April  27, 2022 , the Cybersecurity & Infrastructure Security Agency (CISA) released an updated alert detailing the 15 vulnerabilities routinely exploited by malicious cyber actors in 2021.

It made this statement:

“Globally, in 2021, malicious cyber actors targeted internet-facing systems, such as email servers and virtual private network (VPN) servers, with exploits of newly disclosed vulnerabilities. To a lesser extent, malicious cyber actors continued to exploit publicly known, dated software vulnerabilities—some of which were also routinely exploited in 2020 or earlier. The exploitation of older vulnerabilities demonstrates the continued risk to organizations that fail to patch software in a timely manner or are using software that is no longer supported by a vendor.”

In 2020, many of the systems affected by vulnerabilities related to remote work, including VPNs. Cloud technologies and network credentials were also targeted. In addition, the tremendous growth of remote work since the beginning of 2020 has led to organizations facing challenges carrying out rigorous patch management of endpoints, servers, network devices, etc.

A critical flaw was discovered at the end of 2021 in the Apache Log4j library used extensively across many different applications, including many enterprise systems and remote work solutions. It led to organizations needing to identify any software or applications affected by the critical vulnerability. These efforts are still ongoing by many companies.

The recent Apache Log4j vulnerability and many others underscore the importance of carrying out vulnerability scans of business-critical systems, endpoints, network devices, and applications.

Protecting your organization against weak and breached credentials is a critical component of the overall cybersecurity posture maintained by organizations today. Organizations should consider carrying out vulnerability scans continuously. However, if not continually, it is good to perform a thorough vulnerability scan at least once every quarter or any time significant changes have been made to the environment.

What are the benefits of vulnerability scans?

  • Vulnerability scans are a proactive approach to finding security issues before attackers do
  • They allow prioritizing risk –you can gauge the criticality of a vulnerability which helps to understand the prioritization of remediation
  • The vulnerability scan is a relatively low cost to incur for businesses
  • Vulnerability scans can be automated 
  • Many compliance frameworks require vulnerability scanning
  • It is not intrusive as it only finds vulnerabilities
  • It is less costly than a penetration test since most scans can be performed using automated tools
  • In addition, automated risk-based vulnerability management enables businesses to prioritize the biggest threats through risk scoring saving time and money on remediation activities

What are the limitations of vulnerability scans?

  • They can result in many false positives
  • The vulnerability scan only checks for a particular vulnerability and does not check if it is exploitable
  • Checking and remediating the findings of vulnerability scanners is a manual process
  • Vulnerability scans do not generally find combined paths to compromise as they are only looking for single vulnerabilities, such as missing patches, etc.

What is a penetration test (pen test)?

Another highly valuable cybersecurity tool for organizations is the penetration test. A penetration test (pen test) is a specialized set of activities carried out by a “white-hat” or “ethical” hacker. These skilled cybersecurity experts often work for security companies that carry out pen tests. These ethical hackers carry out a battery of simulated attacks against your network and business-critical infrastructure with a penetration test.

The benefit of the penetration test is the ethical hacker knows the real-world methods the malicious hackers use to compromise your environment. For example, they may use vulnerabilities found in the vulnerability scan to attempt to compromise the network or use various techniques to compromise vulnerable or weak passwords.

With a penetration test, businesses gain visibility into how malicious attackers may successfully attack their systems and what level of risk is involved. In addition, the results of a pen test help companies quantify their risk exposure.

Many compliance frameworks generally require penetration tests, including PCI DSS, and are typically carried out at least once a year. In addition, businesses can carry out their internal penetration tests frequently. However, most compliance regulations mandate that penetration tests are performed by an external entity that can provide a third-party report and verify pen test results.

What are the benefits of penetration tests?

  • Actual white-hat hackers attempting to compromise your network and provide the results of their attempts are invaluable to gaining visibility to weaknesses in cybersecurity defenses
  • The penetration test helps to either verify or rule out false positives from a vulnerability scan
  • They are generally only required to be carried out once a year
  • The pen tester is able to combine potential weaknesses as a real hacker would do to gain visibility to more real-world compromise attempts
  • Most companies include remediation testing in the price

What are the limitations of penetration tests?

  • They can be extremely costly (from $5000 to-$100,000)
  • They happen very infrequently (once a year), so if significant changes are made, it can lead to vulnerabilities existing for quite some time before the next pen test
  • They can be intrusive – to perform a pen test, invasive tests may need to be performed, potentially impacting production systems.

Vulnerability scans vs. Penetration testing

Rather than being an “either-or” tool used by organizations to bolster their cybersecurity, the vulnerability scan and penetration tests serve valuable purposes. First, the vulnerability scan helps to discover vulnerabilities using automated scanning utilities. They help give visibility to missing patches, configuration issues, and other findings. Finally, using the results of the vulnerability scans provides the visibility needed to remediate any issues found.

Penetration testing takes the vulnerability scans a step further. An ethical hacker is used to performing actual penetration testing of your environment using real-world techniques. The pen tester will attempt to use any vulnerabilities found in the environment, which helps to provide proof of whether discovered vulnerabilities are false positives or real concerns.

Vulnerability ScanPenetration Test
DescriptionVulnerability scans find vulnerabilities, including missing patches, configuration issues, etc., using automated tools. The report provided by vulnerability scans helps to prioritize the criticality of the vulnerability for remediation. These can be performed internally and externallyA penetration test uses an ethical hacker as a pen tester to simulate the real-world attack techniques of a malicious attacker. It helps to determine the level of risk in your environment to business-critical resources
Who performsInternal organization or cybersecurity consultant that acts as an Approved Scanning Vendor (ASV).An external cybersecurity consultant or firm generally carries out the pen test, providing the results afterward and a remedial test.
When tests are performedAt least quarterlyOnce a year
CostRelatively inexpensiveExpensive
Required for complianceYesYes

Wrapping Up

Vulnerability scans and penetration tests are beneficial cybersecurity tools. In addition, many compliance frameworks, such as PCI-DSS require vulnerability scans and penetration testing. Using vulnerability scans and penetration tests allows businesses to approach their cybersecurity posture proactively. It is always better to find vulnerabilities and cybersecurity issues before a malicious attacker does.  

Using a reputable, experienced third-party pen test organization, such as Outpost24, helps your business stay secure, compliant, and protected from new and developing threats.

(Last updated on July 20, 2022)

brandon lee writer

Written by

Brandon Lee

Brandon Lee has been in the industry 20+ years, is a prolific blogger focusing on networking, virtualization, storage, security & cloud, and contributes to the community through various blog posts and technical documentation primarily at

Back to Blog