Cybersecurity defenses are in a constant state of adaptation, striving to keep pace with ever-changing hacker tactics. The challenge lies in this reactive stance, as IT security systems frequently find themselves a step behind attackers.
Even companies that meticulously follow IT security guidelines and best practices can remain vulnerable to certain types of cyber-attacks.
Penetration testing allows you to achieve stronger security for your IT infrastructure as a complementary strategy to an IT security audit. Our IT infrastructure management specialists explain.
What is a penetration test?
A penetration test, sometimes referred to as a “pentest”, is a simulation of a cyberattack on a computer system, carried out by a cybersecurity specialist with the aim of exploiting vulnerabilities that hackers could take advantage of. The test can target all aspects of a system, including networks, applications, devices, and physical security.
Penetration tests rely on real-life scenarios to show companies how their current defenses would perform in the face of a large-scale cyber attack, and whether they could ensure business continuity in this context.
Why should companies carry out penetration testing?
Penetration testing enables companies to assess the overall security of their IT infrastructure and detect hidden weaknesses in systems that may not come to light during a conventional audit. This is important, because a company’s security protocols might be strong in one area but weak in another.
Penetration testing identifies weaknesses across a company’s security layers, allowing experts to fix vulnerabilities before they cause significant problems.
More specifically, penetration testing allows companies to achieve the following:
- Verify the effectiveness of security controls currently in place: The customer receives a comprehensive report on the security status of their IT infrastructure, covering applications, network, and physical security.
- Expose real-world vulnerabilities: The company learns which elements of its system are most likely to be attacked by hackers during cyberattacks.
- Ensure compliance: The test results allow the company to verify compliance with established standards designed to protect sensitive data and personal information.
- Strengthen security posture: Based on the test results, the company can prioritize and reduce its vulnerabilities with a tailored security program.
External penetration testing VS internal penetration testing
Not all attacks come from the outside. And not all attacks start from scratch. That’s why there are two main approaches to testing the resistance of an IT system: external penetration testing and internal penetration testing. Each approach reveals different, often complementary, weaknesses.
External network penetration testing
An external penetration test simulates an attack launched from the Internet. The cybersecurity consultant acts as an external hacker, with no specific access to the system. They attempt to penetrate the company’s network from what is visible from the outside: a website, a server, a VPN, a management interface, etc.
The aim is to find out whether a hacker could penetrate the first line of defense. This helps to identify a potential breach before it is used in a real cyberattack.
External testing often highlights vulnerabilities that companies underestimate:
- Ports that can be opened by mistake
- Poorly protected administration interfaces
- Obsolete software
- Passwords that are too simple
- Default configuration that has never been changed
- Configuration errors in a web application
It’s particularly helpful for small and medium-sized enterprises (SMEs) that offer online services or use remote access for things like telecommuting, FTP, or web-based email.
Internal network penetration testing
The internal penetration test simulates malicious or accidental access to the system from inside. Here, it is assumed that the attacker has already crossed the perimeter, perhaps by compromising a workstation, accessing guest Wi-Fi, or obtaining an employee’s access information. This test seeks to determine how well the company can protect its data if a local system is breached or a user account is hacked.
The test simulates what an intruder might do once inside a corporate network. For example:
- Attempt to access confidential files
- Access databases
- Upgrade privileges (from normal user to administrator)
- Install tools to maintain unobtrusive access
- Deploy ransomware
This test assesses the company’s network segmentation, access management, compartmentalization of sensitive data and detection capabilities.
The 3 types of penetration testing
Penetration testing specialists need to adapt their approach according to the risks identified, the business context and the technical scope. To simulate a real hacker attack, a cybersecurity consultant can rely on several strategies:
Black-box penetration testing
Black-box penetration testing involves simulating an attack by a hacker acting without any information about the company, network or server. With only the name of the company as data, the technician will try to find security flaws. It’s a kind of “blind” work. The consultant has no access to network maps, logins or internal documentation. Their task is to find everything on their own, mimicking a cybercriminal launching a random attack on an organization.
By testing what is visible from the outside, including web applications, exposed ports, IP addresses or publicly accessible services, it’s possible to discover configuration errors or flaws in interfaces exposed to the Internet. This approach provides a very concrete overview of the company’s attack surface.
Grey box penetration testing
In a grey box test, the attacker uses a user’s account to try to infiltrate the system. In this scenario, the attacker already possesses some of the information needed to penetrate the IT infrastructure.
This test is more targeted than the black box test. It evaluates what a legitimate user might achieve by overstepping their permissions, such as accessing confidential data, testing access rights, gaining access to other accounts, or bypassing security measures. This is a particularly useful method for testing the robustness of access rights management and the company’s ability to compartmentalize its data and services.
White box penetration testing
This third strategy simulates the most feared type of cyberattack. In this simulation, the hacker – through surveillance, third-party information or spyware – already possesses all the information needed to hack into a corporate IT system.
This type of test thoroughly uncovers the deepest security flaws in a system’s design, configuration, or development. It is often used to test a sensitive or complex environment, where hidden errors could have a serious impact.
How to carry out a computer penetration test: methodology and project phases
A penetration test follows a precise procedure. It’s not just a matter of launching automatic analysis software. Each step is planned, validated and documented. Here’s how it works, step by step.
Step 1: Framing the test
It all starts with a meeting between the company and the cybersecurity provider. The objective is clear: to define the rules of the game. This is the time and place to specify what will be tested, what will not be tested, the periods during which the test can take place, the environments concerned (production, test, cloud, etc.) and prohibited actions (e.g.: do not interrupt an online service). This phase results in an official, formally authorized document bearing the signatures of both parties. This is crucial for both legal compliance and operational transparency.
Step 2: Gather information
Before attacking anything, the tester identifies everything an attacker could learn about the company without needing to access it: public information on domain names, externally visible IP addresses, open ports, technologies in use, accessible services, etc. This phase, known as reconnaissance, relies on specialized tools and open-source research. It maps the attack surface, i.e. the potential entry points.
Step 3: Vulnerability analysis
With a clear view of the environment, the consultant moves on to analysis. They look for known vulnerabilities, configuration errors, out-of-date software, flaws in authentication logic or overly permissive access. To do this, they rely on analysis tools, vulnerability repositories and their experience in the field. This stage is semi-automated, but never 100% mechanical: the human factor remains at the heart of the reasoning. The aim is to identify weaknesses that could be exploited in a real-life context.
Step 4: Exploitation
Once vulnerabilities have been identified, the exploitation phase begins. The tester attempts, within a strictly controlled framework, to break into the system as a hacker would. This could involve accessing a server, connecting to a user account, injecting code into an application, or retrieving confidential files. Each action is documented, and no data is altered. This step makes it possible to measure the concrete impact of vulnerabilities. It’s no longer theory, it’s a demonstration in real-life conditions.
Step 5: Escalation and lateral movements (optional)
In some cases, the test goes a step further. Once access is achieved, the consultant tries to move deeper into the system, changing machines, escalating privileges, and accessing more sensitive resources. This is known as lateral movement. This phase is used to assess whether a local compromise can lead to a complete takeover of the network. This is where we measure the strength of segmentation, user account management and detection mechanisms.
Step 6: Clean-up
When the test is complete, the consultant puts everything back in order. Accesses that were created are deleted, files that were dropped are erased, temporary accounts are deactivated. Nothing is left behind. This step is essential to guarantee system stability and avoid any traces. The company receives an intact environment along with a detailed test report.
What does a penetration test report look like?
The test might be over, but the report is what truly matters. A professional penetration testing service delivers a structured report that is easy for both IT teams and management to understand. It generally contains:
- An executive summary: A few pages cover the main points, the critical flaws, the overall level of risk and the urgent actions to be taken.
- A detailed technical analysis: Each vulnerability is documented in detail, including how it was discovered, its potential impact and how it can be corrected.
- Risk assessment: Vulnerabilities are classified by level of severity (low, medium, high, critical), often according to the CVSS framework.
- Concrete recommendations: Every observation is addressed in the report, which then suggests specific, tailored patches for the company’s environment.
- Proof: Everything is recorded, including screenshots, logs, commands executed, etc.
This report becomes an invaluable IT security management tool. It can also serve as a basis for demonstrating your compliance with certain regulatory or contractual standards.
When is the best time to carry out a penetration test?
The high cost of a real cyber attack means that no company should wait for a real-life scenario before going on the offensive. It’s therefore wise to be proactive about IT security and conduct penetration tests regularly.
Changes to your IT infrastructure can also impact its security. It’s advisable to conduct a penetration test after any of these changes or actions:
- Installation of new equipment
- The launch of an application
- A major update
- A change in applicable regulations
Groupe SL : your IT security resource in Quebec
In short, an IT penetration test is an excellent method for uncovering vulnerabilities in your IT security strategy and determining what you should improve, to avoid becoming the next target of a real hacker.
If you’d like to put your IT infrastructure through a penetration test to strengthen the security of your systems, call on our experienced team of cybersecurity professionals. Following the test, our local supplier can even provide you with a complete IT security plan and the best tools on the market to strengthen your cybersecurity.
