Major Limitations of Penetration Testing You Need to Know

Penetration testing attempts to exploit potential vulnerabilities to identify whether unauthorized access or other types of malicious activities are possible. Also known as a pen test, it is an authorized and controlled attack against your network or computer system to discover susceptible vulnerabilities.

A penetration test may involve attempted breaching of application systems such as frontend/backend servers and application protocol interfaces (APIs). Such targeted security breaches help expose vulnerabilities such as unsanitized inputs that are vulnerable to security breaches (e.g., code injection attacks).

With context to web application security, a pen test is often used to penetrate the application and to try to evade any web application firewall (WAF).

A pen test uncovers different aspects of security testing that may be lacking such as having proper security policies in place, for example, the lack of strong password policies or multi-factor authentication. A pen test provides the simulated experience of dealing with a security breach or an intrusion. It is similar to a fire drill, during which employees are trained to be wary of the possibility of security attacks and threats.

Here are some of the key benefits of penetration testing:

  • Uncovers existing weaknesses in your application(s), configurations, network infrastructure, and your system(s), etc.
  • Tests your cyber-defense capability to deal with cyber attackers and malicious activities
  • It has a great impact on the operations of a business as it exposes potential threats that may cause loss of accessibility or downtime
  • Maintains the credibility and trust of your stakeholders

All of these benefits seem to justify the effort that organizations put into penetration testing. Moreover, many companies conduct a pen test to adhere to the guidelines set by the Payment Card Industry (PCI) Security Standards Council to become PCI compliant.

Penetration testing has an array of benefits and helps identify any potential vulnerabilities, however, it alone can’t prevent data breaches. In reality, even the most carefully tested and analyzed infrastructure or applications could fall victim to security breaches or attacks.

The Limitations of Penetration Testing

With the existing cyber threat landscape increasing with evolving threats, and opportunistic exploits of faulty deployments and simple misconfigurations, pen testing alone is not sufficient.

Despite offering a gamut of benefits, there are some major limitations of penetration testing that can drastically impact your business.

Here are some of the major limitations of penetration testing that you should know:

Limitation of Time

Often, penetration testing is carried out as a timeboxed assessment that needs to be completed in a predefined time period. The testing team has to identify potential threats and vulnerabilities, and produce results within this specified time period.

Penetration testers also have to create a report at the end of the test which includes a description of the vulnerabilities identified, the methodology used, and an executive summary. They also have to take relevant screenshots at regular intervals and add them to the final report once the test has been completed.

In contrast, attackers are not constrained by time and they can have as much time as needed to identify and exploit more vulnerabilities. So timeboxed assessments like penetration testing give the attacker an edge over penetration testers, allowing them more time to exploit the application.

Hence, in addition to penetration testing, we recommend a white box assessment, a testing method that evaluates the internal structure, coding, and design of the software and the network, basically, the tester has full access to how the network, applications are designed. It helps identify internal security loopholes and broken or improperly structured flows in coding processes or in the network configuration. It also tests each function, object, and statement on an individual basis.

Limitation of Scope

Some organizations selectively perform security testing, which means they do not test everything. This may be due to a lack of resources, budget constraints, poor security policies, or other factors.

Similarly, penetration testers have limited scope and they often have to leave many parts of the system unchecked because of these constraints.

For instance, many times, exploits depend on the interactions of systems. So if the scope of a pen test is limited to one system, vulnerabilities that arise from the interactions of systems won’t be discovered.

This leads to an insufficient and poor quality penetration test that may cause damage to your organization at a later stage.

Limitation of Access

Often the testing team has restricted access to the target environment in a pen test.

For example, networks are often divided into segments and the penetration testing has access to only those specific segments that have servers or are accessible from the internet so that the team can simulate a real-work attack.

However, such a pen test with limited access will not be able to reveal configuration issues and potential vulnerabilities on its entire network.

An efficient way to detect vulnerabilities is to conduct white box testing along with penetration testing. This way, the tester will have complete information about the network, the application’s source code, the servers that it runs on, its detailed network infrastructure, and the IP addresses involved.

White box network vulnerability assessment helps to expose security threats by attacking the network from different angles. For applications, you can conduct code reviews that will help you discover security threats and weaknesses that might not be apparent from dynamic testing such as encryption algorithms, how passwords are stored, etc.

Limitation of Methods

Conducting a penetration test is intended to exploit systems, typically by doing things in ways that the system was not intended to handle.

During a penetration test, it is possible that the target infrastructure or system may crash. So the penetration testing team is restricted to use only a specific set of methods that avoid downtime or system crashes.

For instance, creating a distributed denial of service (DDoS) flood to divert a network or system administrator by using another method of attack is usually an ideal way for an attacker to bring down an organization.

However, such methods are likely to be avoided for penetration testing by teams as they tend to cause downtime of the system.

Other times, automated techniques are off limits and this may leave the system exposed to vulnerabilities that are prone to attackers such as script kiddies (skiddies) who are waiting to exploit such automation in internet-accessible systems.

These attackers are unskilled individuals who are constantly on the lookout to exploit well-known and easy to find weaknesses in computer systems to gain access to them without comprehending the consequences.

Limitation of Skill Sets of a Penetration Tester

The success and quality of the penetration test are directly proportional to the experience and skills of the penetration testing team. Each penetration test can be divided into three broad categories: system, network, and application penetration testing.

A penetration tester who is skilled and experienced in network penetration testing might not be able to perform a successful application penetration test. With continuously evolving and upgrading technologies, it is becoming more difficult to find a skillful person who can conduct a high-quality penetration test.

Meanwhile, more skilled attackers who have time can potentially do a lot of damage to the system.

While a tester may have in-depth knowledge about Apache web servers, they may be less experienced with Internet Information Services (IIS) server. Having experience with the same technology plays a vital role in the success of a penetration test.

Limitation of Custom Exploits

Often times, the penetration testing team is required to think out-of-the-box and create custom exploits. For instance, in some highly secure environments, normal pen testing tools and frameworks are of little use.

So the penetration team has to build custom exploits that are effective in secure environments as well. Creating a custom exploit also entails writing scripts manually to define the path of the intrusion to reach the target for conducting a pen test.

This can be extremely time consuming and it is not an efficient way to conduct regular security tests. Additionally, it is not a part of the skill set of most penetration testers. Manually writing scripts and creating custom exploit code can dramatically impact the budget and time taken to conduct the test.

Limitation to Experiment

Penetration testers are allowed to use only client-approved exploitation frameworks and tools. Since not every tool is all-in-one and they may lack some features or miss some parts of the test, the testing team will have to find alternatives to carry out the test effectively.

Moreover, stringent instructions from the client and higher-level management can restrict the penetration team’s ability to experiment with the approved scope. On the other hand, attackers are free to work their way around security tests and create new paths to attack.


Penetration testing plays an important role in finding security vulnerabilities. However, you should be aware of its limitations as they can have a massive impact on your organization. Eliminating penetration testing is not an ideal solution, but you can always combine it with other effective security methods and processes to carry out proper tests.


Cypress Data Defense was founded in 2013 and is headquartered in Denver, Colorado with offices across the United States. Our goal is to help organizations secure their IT development and operations using a pragmatic, risk-based approach. The diverse background of our founders allows us to apply security controls to governance, networks, and applications across the enterprise.

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