Man standing in front of graphic interface showing vulnerability scanning and penetration testing information

Penetration Testing vs Vulnerability Scanning: Why You Need Both

Vulnerability scanning and penetration testing are the two main methods by which an organization tests its network against attackers. What’s the difference between the two? The main difference is the human element: vulnerability scans are largely automated and seek out known and published exploits, while penetration testing employs actual humans who get creative in trying to find an unauthorized path into the network.

Given the current cybersecurity landscape, the answer for most organizations is going to be that both are necessary

Organizations are often confused as to where they individually fall on this spectrum of testing and vulnerability management. Is one or the other more appropriate? Would the use of both services be redundant, or a waste of time and money? Given the current cybersecurity landscape, the answer for most organizations is going to be that both are necessary — at least periodically.

The virtues of vulnerability scanning

Vulnerability scanning tends to be the lower-cost option, and the one that comes with less complication and potential business interruption. It’s a vital service for keeping up with new vulnerabilities in both hardware and software, but it is far from a complete network security checkup and has its limitations that one should be aware of.

When security researchers discover repeatable vulnerabilities in software or hardware, the standard procedure is to quietly notify the publisher/manufacturer who will then spend some days or weeks patching the issue. After the patch is released, the general public is notified. Of course, that notification is going out to all the cyber criminals of the world as well — that’s why it’s so crucial to keep up with new patches.

Man and woman IT staff working in data center with laptop doing vulnerability scanning

The sheer number of products that must be continually patched creates a big headache for many organizations. The process is not automatic in most cases, with manpower required to at minimum check to ensure that the update did not create configuration issues or some loss of function. However, it is vital to identify vulnerabilities early as the cost of a data breach is usually much greater.

Vulnerability scanning assists in this process by taking a high-level look at all of the computers, devices and network components in the organization. All of these parts of the network are essentially checked against a database of known vulnerabilities by automated software, which ultimately returns a list of potential issues that the organization’s IT staff can work from. The best of the vulnerability scanning services will check for tens of thousands of known weaknesses as a part of this process.

Though it is usually a smart voluntary risk management strategy, vulnerability scanning is also increasingly becoming a regulatory requirement. Industries that deal in especially sensitive personal data, such as financial services companies, often have special requirements mandating that a vulnerability assessment be done at certain intervals. And though it is not a specific requirement, the EU’s Information Commissioner’s Office (ICO) has issued General Data Protection Regulation (GDPR) guidance advising all organizations to “run regular vulnerability scans and penetration tests to scan your systems for known vulnerabilities.”

Vulnerability scanning is also increasingly becoming a regulatory requirement

The greatest strength of vulnerability scanning is that it’s very affordable and easy to do. The scans complete quickly, they can be scheduled to run automatically without interrupting normal business, and they are so inexpensive even small businesses can easily afford to have them done weekly or monthly. However, there are some significant weaknesses as well. One is that they tend to kick out a long list of potential “false positives” that IT staff may have to spend time verifying. Another is that the approach relies entirely on known vulnerabilities. It won’t spare you from undisclosed vulnerabilities that attackers are sitting on, and it can’t simulate a hacker getting creative with approaches such as email phishing or social engineering by phone.

Ultimately, vulnerability scanning should be considered an element of the regular patching and updating process. It helps to keep you on track and ensure that big vulnerabilities aren’t just left hanging out there.

The positives of penetration testing

Penetration testing takes data security to the next level. You essentially commission at least one “ethical hacker” to pretend to be a bad guy and try to break through your defenses, finding vulnerabilities wherever they can. The penetration tester will do more than just scan for known vulnerabilities; they’ll try to scam employees, look for usable intelligence elsewhere on the internet, and use cracking methods like credential stuffing and SQL injections.

Penetration testing is the best way to get a full and accurate assessment of your current security posture

Since penetration testing is much more in-depth and has more human involvement, it costs quite a bit more than vulnerability scanning. Tests of small systems can potentially be completed in one day, but more complex networks can take up to several weeks to fully analyze.

In spite of the cost and the time it can take, penetration testing performed by qualified security services is the best way to get a full and accurate assessment of your current security posture.

Penetration testing vs vulnerability scanning

Team meeting in office making decisions on penetration testing and vulnerability scanning

While most businesses will find that they need both of these services at some point, they are often left confused as to how frequently each should be done.

There is no one-size-fits-all solution when it comes to security risk mitigation; it depends to a great deal on the type of information you secure and how frequently you expect to be targeted. However, at minimum, most small businesses will find they want penetration testing at least once a year and vulnerability scans done at least once per quarter (though at least monthly is strongly recommended due to current cybersecurity realities).