Vulnerability scanning vs. penetration testing explained


Generally, vulnerability scanning and penetration testing are used interchangeably by many people, either because of misunderstanding or marketing hype. The differences between vulnerability scanning and penetration testing, as required by PCI DSS, have caused confusion within the industry. Both the terms are different in terms of their objectives and other means.

Vulnerability is a weakness or flaw in a system due to a weak password, coding, input validation, misconfiguration, etc. The attacker attempts to identify these vulnerabilities and then hack into the system.

Vulnerability assessment is a proactive and systematic strategy to discover the vulnerability. Required by industry-standard like DSS PCI from a compliance point of view, it is practiced to discover unknown problems in the system. A vulnerability assessment is a comprehensive assessment of the information security position (result analysis).

Penetration testing evaluates the security of a computer system or network by simulating an attack. It is a proactive and systematic approach to security assessment. It replicates the actions of an external or/and internal cyber attacker/s intended to break the information security and hack the valuable data or disrupt the organization’s normal functioning.

This post will discuss some key differences between vulnerability scanning and penetration testing.

Vulnerability Scanning

The goal of a vulnerability scan is to find, rank, and report vulnerabilities that, if exploited, could lead to a system compromise, either intentionally or unintentionally. Vulnerability assessment identifies flaws and suggests ways to address them. A vulnerability scan is a helpful automated tool that gives you a bird’s-eye view of your network’s security. Vulnerability scanning will only alert you to potential system flaws.

It is done at least quarterly or after significant changes relatively quickly, typically several seconds to several minutes per host, using various automated tools combined with manual verification of identified issues. A vulnerability scan reports potential risks posed by known vulnerabilities, ranked in accordance with NVD/CVSS base scores associated with each vulnerability.

External vulnerability scans are performed by an ASV from outside the target organization, and the risks are ranked using the CVSS. On the other hand, qualified personnel conduct internal vulnerability scans from within the target organization (and do not require an ASV). Risks are ranked according to the risk-ranking process defined in PCI DSS Requirement 6.1.


  • Provides false positives
  • Companies must check each vulnerability manually before testing it again
  • It does not confirm whether a vulnerability is exploitable
  • Cannot identify potential access path
  • Requires high technical skills for tester
  • Cannot exploit flaws

Vulnerability scanning tools

  1. Nessus is a simple-to-use vulnerability scanning tool that helps you save time and effort by scanning, prioritizing, and remediating vulnerabilities. It defines its operating system by testing all of the devices’ ports individually. The operating system is then examined for any known vulnerabilities.
  2. OpenVas assists in performing in-depth vulnerability scanning and management pack by scanning all network devices and servers. It works by selecting a target, such as a specific IP address and then performing scans according to the preferred scanning type to identify flaws.
  3. Netspark is a website application testing tool that uses a security scanner to automate the process. The software detects Cross-site scripting and SQL injection attacks. Developers will benefit from this because Netspark can be used on their websites, web services, and web applications.

Penetration Testing

The purpose of the penetration test is to identify ways to exploit vulnerabilities to circumvent or defeat the security features of system components. In other words, penetration testing only answers the question, “can anyone break into the system security, and if so, what harm can he do?”

It is carried out at least once a year and whenever there are significant changes, using a manual process that may include vulnerability scanning or other automated tools, and results in a comprehensive report. Depending on the scope of the test and the size of the environment to be tested, engagements can last days or weeks. If more scope is discovered, tests may become longer and more complex.

The test describes each vulnerability verified and/or potential issue discovered, including SQL injection, privilege escalation, cross-site scripting, and deprecated protocols, to name a few, which pose more specific risks, including specific methods for exploiting it and the extent to which it can be exploited.

As opposed to vulnerability scanning, penetration testing takes a much more in-depth look at your company’s security systems. It can detect sophisticated threats hidden within your company’s infrastructure. You gain critical insights into the present state of your security measures and the solutions needed to improve them by simulating a real-life attack on your organization and actively testing vulnerabilities.


  • Identifies potential access paths
  • Identifies only those who pose threats
  • May not identify obvious vulnerability
  • Cannot provide information about new vulnerabilities
  • Cannot identify server-side vulnerabilities

Penetration testing tools

  1. Kali Linux is a popular Linux penetration testing tool used for high-end security auditing and penetration testing. It carries out its operations by combining a set of powerful built-in tools that excel at reverse engineering security research.
  2. Metasploit can find vulnerabilities, manage security assessments, and develop defense strategies. It works by exploiting code and writing, testing, and executing it. It comes with powerful tools for evading destruction, running attacks, enumerating networks, and testing target network vulnerabilities.
  3. Wireshark captures and interprets network packets while also allowing offline and live capture. Security professionals can use the capture feature to examine the source and destination protocols. The program is open-source and works on various platforms, including Windows, Solaris, FreeBSD, and Linux.
  4. Burp Suite is capable of crawling web-based applications automatically. When attempting to gather information on web-based applications or analyzing requests between a browser and its destination, this tool would be used. The paid version includes all of the necessary features for advanced penetration testing.

To sum up, both vulnerability scans and penetration tests have different functionality and approach. A vulnerability scan attempts to improve the security system and develops a more mature, integrated security program, while penetration testing only shows your security program’s effectiveness.