Pen testing vs. vulnerability scanning: What’s the difference?

What is a pen test?

A pen test is a series of hacking methods aimed at helping IT security professionals identify vulnerabilities to remediate them and verify their removal. Pen tests are a form of ethical hacking as they often involve the use of unethical hacking tools in a fully authorized manner.

Security professionals receive permission from the organization to perform these types of tests. The intention isn't to steal data or cause harm to assets. Instead, the goal is to mimic tactics and tools that nefarious actors might use with the intent of identifying weaknesses in a business's IT security posture. Once identified, these vulnerabilities can be fixed prior to a real-world compromise.

A pen test is a relatively broad term for the following six underlying testing steps:

1. preparing and performing reconnaissance;
2. constructing an attack plan;
3. selecting a team or automated service to carry out the tests;
4. choosing target data types;
5. executing the test; and
6. reviewing results and analyzing findings.

Pen tests should be conducted on a regular basis. For most organizations, tests are performed every six to 12 months.

What is vulnerability scanning?

Vulnerability scanning is performed as part of a pen test. As mentioned above, step two of a pen test lifecycle involves the construction of an attack plan. Depending on the target types and whether the attack methods include internal, external or blind/double-blind testing methods, this may involve the use of one or more pen test tools. These tools may focus on tasks such as the following:

• intelligence gathering;
• gaining access to applications or systems;
• privilege escalation; and
• payload inspection/analysis.

The first goal -- intelligence gathering -- uses various scanning tools to identify and map a network and determine whether horizontal or vertical access can be achieved. One specific tool used in this step is a vulnerability scanner. A vulnerability scanner scours a network to identify, examine and inspect various corporate systems and apps to detect if they are susceptible to known vulnerabilities. In the case of a pen test, a vulnerability scan is manually performed and targets specific digital resources that are in scope for the particular pen test being conducted.

Vulnerability scanning is not only performed as part of a pen test, however. Automated vulnerability scans are commonly conducted across an entire corporate network at regularly scheduled intervals. These automated scans are meant to provide up-to-date reports of potentially vulnerable systems and software so security administrators can prioritize and schedule patching efforts. Thus, the two uses of a vulnerability scan serve similar, yet distinctly different purposes.

What about automated pen testing?

Further clouding the confusion between pen tests vs. vulnerability scanning is the recent interest in conducting automated pen tests. For years, pen testing was manual and fully managed by one or more security administrators, and one method used during the execution phase was running automated vulnerability scans against said pen test targets.

The problem is that manual pen tests are known to be time-consuming and costly. Additionally, targeted testing of vulnerabilities once or twice a year is no longer sufficient given the growing threat landscape. That said, pen tests remain a necessary part of an organization's complete cybersecurity strategy.

To counter the high costs incurred with manual pen tests, AI is now being injected into pen test platforms to automate most of the testing lifecycle steps on an administrator's behalf. Both pen tests and vulnerability scans can now be largely automated.

Keep in mind, however, that, while automated processes do occur on both, the actual methods and goals for automated pen testing and scheduled vulnerability scanning continue to differ greatly.