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What is a Penetration Tester in Cybersecurity?

What is a Penetration Tester

The best way to determine if something works properly is to test it under simulated conditions before putting it into action. People test drive cars before buying, companies hold fire drills, and software developers extensively test their products before releasing them.

And so it is with cybersecurity systems. When organizations want to see if their cybersecurity measures are adequate, they conduct simulated attacks to determine their security effectiveness. Penetration testing is part of this procedure.

This article answers the question, “What is a penetration tester?” and explores various aspects of penetration testing, including the phases, methods, tools, and advantages. We’ll also share a cybersecurity bootcamp you can take to boost your skills and career.

So, let’s start with the basics. What’s penetration testing?

What is Penetration Testing?

Penetration testing, also called pen testing, is a simulated cybersecurity exercise where a cyber-security expert, typically a cybersecurity penetration tester, tries to find and exploit the target computer system’s vulnerabilities. This attack aims to identify weak spots in the organization’s IT system defenses that intruders could take advantage of.

Penetration testing usually involves breaching attempts against any given number of application systems, such as frontend/backend servers or application protocol interfaces (APIs), to discover vulnerabilities, like unsanitized inputs, which are prone to code injection attacks.

Also Read: How To Get Into Cybersecurity: A Complete Guide

Who and What is a Penetration Tester?

The most effective means of conducting any test is to have someone objective. Consequently, the best penetration testers are professionals hired from outside the organization, with little to no knowledge of the organization’s defenses. This tester best represents the intruder who would try to gain access: someone who doesn’t work for the company.

These cybersecurity professionals are typically called “ethical hackers,” as the company recruits them to try breaking into their IT systems to determine how effective the organization’s cybersecurity measures are, testing them under “actual conditions,” as it were.

Some cybersecurity penetration testers are reformed criminal hackers, subscribing to the adage “It takes a thief to catch a thief.” Other testers are professionals who have undergone penetration tester certification or gained a college degree in pen testing.

However, penetration testing comes in many forms. Let’s review them.

What Are the Different Methods of Pen Testing?

There are five primary penetration testing forms, although some are called by different names.

  • Open-box pen testing. With open-box testing, the hacker is given information regarding the target company’s security info ahead of time.
  • Closed-box pen testing. Closed-box testing is also known as a ‘single-blind’ test, where the hacker has no background information regarding the target, just the company name.
  • Covert pen testing. Covert pen testing is also called a ‘double-blind’ pen test. In this scenario, almost no one in the organization knows that the pen test is happening, even the IT and cybersecurity professionals responding to the attack. Consequently, the hacker must have the scope and other test details in writing beforehand to avoid potential problems with law enforcement!
  • External pen testing. With external pen testing, the ethical hacker is pitted against the company’s external-facing technology (e.g., website and external network servers). Often, hackers may not even be allowed inside the company’s building. Thus, external pen testing is often conducted remotely or with a truck or van parked nearby.
  • Internal pen testing. On the other hand, an internal test has the ethical hacker performing the test from the company’s internal network, determining how much damage a disgruntled employee can wreak from behind the company’s firewall.

What is a Penetration Tester, and How Do They Test IT Assets?

Penetration testers test different IT areas in multiple ways. Here’s a breakdown of the various pen-testing approaches for specific IT infrastructure parts.

  • APIs. Both automated and manual pen testing techniques are used to spot security risks and vulnerabilities. Pen testers look for excessive data exposure, broken object-level authorization, user authentication, lack of resources/rate limiting, and more.
  • CI/CD pipeline. Current DevSecOps practices integrate automated and intelligent code scanning tools into CI/CD pipelines. In addition to static tools that locate known vulnerabilities, automated penetration testing tools can be integrated into CI/CD pipelines to simulate how a hacker can compromise an application’s security. Automated CI/CD penetration testing can uncover hidden vulnerabilities and attack patterns that would otherwise go undetected with static code scanning.
  • Cloud. Cloud environments significantly differ from traditional on-premises environments and must be handled differently. Typically, the organization using the environment and the cloud services provider share the security responsibilities. As a result, cloud pen testing requires a specialized skill set and the appropriate experience to investigate the different aspects of the cloud, such as APIs, configurations, databases, encryption, storage, and security controls.
  • Containers. Containers obtained from Docker typically have vulnerabilities that hackers can exploit at scale. Containers and their environments often run the risk of misconfiguration. Professional penetration testing can reveal both risks.
  • Embedded devices (IoT). Embedded and Internet of Things (IoT) devices such as automobiles, in-home appliances, medical devices, and smartwatches have specialized software testing requirements because of their power constraints, longer life cycles, remote locations, and regulatory requirements. Cybersecurity experts perform thorough communication analyses alongside a client/server analysis to spot the most relevant defects.
  • Mobile apps. Testers use automated and extended manual testing to search for vulnerabilities in application binaries running on mobile devices and their corresponding server-side functionalities. Server-side vulnerabilities include authentication, authorization, cryptographic, session management, and other typical web service vulnerabilities.
  • Mobile devices. Pen testers use manual and automated analysis to locate vulnerabilities in application binaries running on mobile devices and their corresponding server-side functionalities. Binary application vulnerabilities can include authorization and authentication issues, client-side trust issues, misconfigured security controls, and issues with cross-platform development frameworks. Server-side vulnerabilities typically include cryptographic issues, session management, authentication and authorization issues, and other basic web service vulnerabilities.
  • Networks. This pen testing form identifies all security vulnerabilities in external networks and systems. Cybersecurity experts typically use a checklist that includes test cases for SSL certificate scoping issues, encrypted transport protocols, use of administrative services, and other cases.
  • Web apps. Web application penetration testers study the effectiveness of security controls and search for attack patterns, hidden vulnerabilities, and any other possible security gaps that can compromise a web app.

Also Read: Cybersecurity Job Description: A Complete Guide

What are the Phases of Penetration Testing?

Regardless of the kinds of tools cybersecurity penetration testers employ, most testing falls into a common pattern. Here are the steps in a typical plan of attack used by penetration testers.


The pen tester gathers as much information about the target as possible via public and private sources to better inform the attack strategy. These sources include domain registration information retrieval, Internet searches, nonintrusive network scanning, social engineering, and sometimes even old-school dumpster diving. This stolen information helps pen testers plot the target’s attack surface and identify possible vulnerabilities. The reconnaissance’s extent varies with the test’s scope and objectives; it can be as easy and direct as making a phone call to walk through the system’s functionality.


Pen testers use a collection of tools to examine the target systems or websites for weaknesses such as application security issues, open services, and open-source vulnerabilities.

Gaining Access

Now that the hackers have the information they need, it’s time to access the target. Attacker motivations include taking, altering, deleting data, moving funds, or damaging a company’s reputation. To conduct each test case, penetration testers decide the best tools and techniques to access the system, whether through a weakness like SQL injection, malware, social engineering, or some other tactic.

Maintaining Access

Once penetration testers gain access to the target, they must stay there long enough to withdraw data, change it, or damage functionality.

Types of Pen Testing Tools

Everyone knows you need the right tool for the right job. Penetration testers have access to an impressive array of tools and resources, including:

  • Exploitation tools to gain a foothold to a system or access to its assets
  • Post-exploitation tools are used to interact with systems, maintain and expand access, and achieve the attack objectives
  • Proxy tools like specialized web proxies or basic man-in-the-middle proxies
  • Reconnaissance tools for finding network hosts and discovering open ports
  • Vulnerability scanners for finding APIs, network services, and web application issues

The Pros and Cons of Penetration Testing

Penetration testing has its upsides and downsides, although, to be fair, the benefits outweigh the drawbacks.

Pros of Penetration Testing

  • Pen testing finds holes in upstream security assurance practices, like architecture analysis, automated tools, configuration and coding standards, and other lighter-weight vulnerability assessment functions
  • Pen testing locates known and unknown software flaws and security vulnerabilities, even minor glitches that won’t raise much concern but could eventually be used in a more complex attack pattern
  • Pen testing can imitate how most hackers behave and attack any system, closely simulating possible real-world adversaries

Cons of Penetration Testing

  • Pen testing Is labor-intensive and expensive
  • Pen testing is great for finding vulnerabilities but does not comprehensively prevent bugs, glitches, and flaws from finding their way into production

Also Read: Cybersecurity Salary Guide: How Much Can You Make?

How Does Pen Testing Differ from Automated Testing?

Automated testing requires fewer people to operate, and it works faster. Automated testing tracks results automatically and sends them to a centralized reporting system.

On the other hand, manual pen testing can locate weaknesses and vulnerabilities not included on lists from which automated testing works. Manual tests are also better at spotting false positives that would otherwise be flagged by automated testing. Finally, pen testers are human, like their adversaries, and so can think like them.

Finally, if you want more information on how to become a penetration tester, check out the following section.

Do You Want a Career in Cybersecurity?

So, what is a penetration tester? A good penetration tester needs a full range of cybersecurity skills, and this online cybersecurity course gives you expertise in defensive and offensive cybersecurity skills and teaches you what you need to know about digital forensics, network security, and more. reports that cybersecurity professionals in the United States earn a yearly average of $101,822. So, sign up for this highly informative 24-week course and prepare for an exciting cybersecurity career!

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