Does a Pentest Have to Be Done Only Once?

Penetration tests are indispensable for identifying vulnerabilities in IT systems and remediating them effectively. Many companies assume that a single pentest before rolling out a system is sufficient. In this article, we explain why this assumption is a mistake and how often you should actually perform penetration tests to protect your systems as thoroughly as possible.

Identify Vulnerabilities Early with Pentests

Wherever information is exchanged, there is a risk that third parties may gain unauthorized access. This risk can never be entirely ruled out. Systematic testing is therefore a crucial tool for identifying security vulnerabilities. It provides your organization with a holistic view of potential attack surfaces and delivers the information needed to close security gaps. The BSI defines penetration testing as "the controlled attempt to penetrate a specific computer system or network from 'outside' to identify vulnerabilities."

How Secure Is Secure Enough?

High IT security costs rank among the biggest barriers to improving IT security. As a result, many companies ask how many penetration tests are truly needed to secure a system. In a penetration test, we put ourselves in the attacker's shoes. We systematically work through various attack scenarios to verify in practice whether the system can withstand them. Once a system has passed a penetration test, all security vulnerabilities have been found and addressed. But is a single penetration test at the outset really enough?

Why One Pentest Is Not Enough

IT systems are not static. Web applications are constantly updated, as are mobile apps and other systems. Every change to the code or configuration can potentially open new doors for attackers. At the same time, attack methods continue to evolve: an API considered secure today may be exploited tomorrow.

Pentests do more than uncover security vulnerabilities -- they also sharpen security awareness within the team. After all, the human factor is often one of the weakest links in any security system. A strong awareness of potential threats is therefore essential for improving IT security across the organization. The biggest enemy here is complacency. The longer employees work without an incident or pentest, the more likely they are to become lax about security standards and procedures.

How Often You Should Conduct Penetration Tests

So how often should you perform penetration testing? The answer is: frequently enough to identify newly emerged vulnerabilities before they can be exploited. The ideal cadence depends on several factors. A young web application under active development requires more frequent penetration tests than systems with few changes. Yet even for stable systems, regular testing at intervals of no more than one year is critical to maintaining resilience against attacks.

Testing Systematically and on Demand

Systematic and efficient penetration testing requires an accurate inventory of your various assets (databases, servers, applications). This ensures, on one hand, that no assets -- and thus no potential attack vectors -- are overlooked. On the other hand, it allows you to categorize assets and create a dedicated test plan for each class. Through regular, closely spaced test cycles, you ensure that new vulnerabilities are identified before an attacker can exploit them.

Regular Pentesting Protects Your Assets

Regular penetration tests are essential to protect IT systems across your organization -- a point also emphasized in the NCSC's guidance on penetration testing. These tests uncover security vulnerabilities whose exploitation could cause significant damage. As a general rule, penetration tests should be conducted at least once a year. Depending on the assets in your organization, however, more frequent testing may be warranted. Although these tests represent an additional investment, they pay off in the long run: they safeguard access to your company's most critical information.