What You Need to Know About Internal Penetration Tests

Businesses have recognized the value of cybersecurity in recent years. Pen testing, also known as penetration testing, is a valuable method for testing and identifying possible ways for attackers to exploit weaknesses in your properties. Prioritization, pentesting to avoid financial losses, defending brand integrity, and retaining consumer confidence are ways to gain intelligence.

What are the Types of Penetration Test?

Penetration tests have advantages and disadvantages according to their types. Organizations can choose to perform only one form of a penetration test or multiple types to get a complete picture of their security situation.

See Also: What You Should Know About External Penetration Testing

Black, gray and white box test; Used to test the cyber vulnerability of infrastructures such as applications, cloud, and connected devices. Colors also identify test teams, and each color team offers a unique function for testing the organization’s cyber readiness.

  • Black box: When performing a black box assessment, penetration testers have limited knowledge of the network. For example, they know the hostname and IP of a public server, but they don’t know about network infrastructure, operating systems, or security protections. While trying to break into the network to discover as many vulnerabilities as they can find, this method simulates the “real world” environment to find vulnerabilities using most of the tools attackers will use.
  • White box: In this scenario, testers have more access and information about the environment, such as administrator rights and configuration files. This type of testing takes less time than a black-box test but does not show how attackers can gain unauthorized access from the outside. However, if an attacker has gained internal access and rights, they can provide insight into vulnerabilities.
  • Gray Box: The gray box test falls somewhere between the black box and the white box test. The customer divulges some restricted data, such as user login credentials or a network summary. The scope and what information and access are provided depends on the customer’s testing requirements. The gray box has the advantages of black-box testing, but with additional information provided, it can also perform deeper testing as needed.
  • Red team: Red team members employ aggressive security techniques based on specific goals, such as breaking into a database and extracting sensitive records. The red team simulates an attacker and looks for vulnerabilities that could be exploited.
  • Blue team: The blue team is responsible for defending against the attacks of the red team. They use logs, and traffic captures, SIEM, and threat intelligence data to detect and protect against red team attacks. The blue team is an organization’s internal security team. The exercises with the red team it is aimed to improve the defense of the internal team and its response to attacks.
  • Purple Team: A purple team is formed by combining the efforts of the red and blue teams. This type of interaction allows the blue team to measure their detection and incident response capabilities against real-world-like threats.

An organization’s choice of testing will depend on what kind of information they want to learn. However, it would help if you also decided on the penetration testing scope and what types of systems should be included in the test.

Which Systems Can Be Tested With Internal Penetration Test?

Different areas of the network and systems can be tested by taking the web, mobile, and cloud applications or systems such as network and wireless infrastructure into the scope of penetration testing.

  • Web Applications – When testing against a web application, the tester analyzes the site to understand the application and performs tests such as open ports, checks default or misconfigured settings. Testers search for detailed error messages and review login pages or online forms. Some of the vulnerabilities that testers look for include SQL injections, cross-site scripting, encryption flaws, or XML and template injections.
  • Mobile Applications – Similar to web application testing, mobile tests will include an operating system evaluation and application analysis. Penetration testers analyze various factors such as file system, runtime, TCP, and HTTP attacks. Potential vulnerabilities that may arise are insecure APIs, sensitive file structures, plain text traffic, and SQL injections.
  • Infrastructure and Network – The purpose of infrastructure and network testing is to identify exploitable vulnerabilities in network devices, systems, and hosts. Penetration testers will want to identify protocols in use such as CDP, WEP, and SNMP. They also try to discover network device models and what software versions are in use. The vulnerabilities most likely to be discovered include the use of weak or default passwords, missing patches, unnecessary open ports, and SNMP v1 or v2 still in use.
  • Wireless Penetration Test – Wireless penetration test includes attempts to break WEP and WPA encryption to gain access to the network. Other attacks, such as Man-in-the-Middle (MitM) attacks, are also attempted and trick wireless clients into connecting to a rogue access point.
  • Endpoint / Kiosk PC Penetration Test – These penetration tests attempt to exit a kiosk PC or other locked device and gain elevated privileges or access sensitive data otherwise inaccessible.
  • Cloud Applications – Testing public cloud applications means you need to notify the provider before starting any testing, and some restrictions are expected on what types of tests can be performed. Cloud penetration tests may include applications, storage, virtualization, and compatibility. Therefore, depending on the test’s scope, testers can check items such as data access, virtual machine isolation, and orchestration compliance. Test results may include incompatible encryption, virtual machines that are not adequately isolated, API vulnerabilities, and weak passwords.

The importance of having a solid security posture requires testing security to make sure it works as expected. Also, those charged with managing the security infrastructure must maintain appropriate standards and procedures.

See Also: PCI DSS Penetration Test Requirements

Penetration testing by a third party provides an unbiased perspective on the organization’s cybersecurity posture. Persons performing penetration tests must be certified and experienced. A third-party tester’s value is that it allows for the ability to see red team activities in a threat intelligence system and create automated workflows for blue team activities.

What is the Scope of Internal Penetration Test?

Internal Penetration Testing differs from a vulnerability assessment in that it exploits vulnerabilities to determine what information was exposed. The Internal Penetration Test simulates an actual attacker’s actions using weaknesses in network security without the usual dangers.

Internal Penetration Test examines internal IT systems for any weaknesses that could be used to compromise the network’s privacy, availability, or integrity, thus allowing the organization to address each weakness.

In internal penetration testing, security testing methodologies are followed, which can include:

  • Internal Network Scanning
  • Port Scanning
  • System Fingerprint
  • Services probing
  • Exploit Research
  • Manual Vulnerability Testing and Verification
  • Manual Configuration Weakness Testing and Verification
  • Limited Application Layer Testing
  • Firewall and ACL Test
  • Administrator Privilege Elevation Test
  • Password Strength Test
  • Network Equipment Security Controls Test
  • Database Security Controls Test
  • Internal Network Scan for Known Trojans
  • Third-Party / Vendor Security Configuration Test

Why Should You Do an Internal PenTest?

Internal Penetration testing allows organizations to test how an attacker can access confidential information, including Non-Public Personal Information (NPPI), to perform unauthorized data disclosure, abuse, alteration, or destruction.

Once the perimeter defenses of the organization’s internal network are compromised, it is exposed to threats, such as external attackers or insider malicious individuals who attempt to access or damage sensitive information or IT resources. Therefore, organizations should also test the internal network as often as they do the external environment.

See Also: What are the Requirements for PCI DSS Vulnerability Scanning?

The Best Practice recommends that each organization perform an Internal Penetration Test as part of their regular Security Programs to secure internal network defenses.

What are the Steps to Perform an Internal Penetration Test?

Sometimes the best defense is a good attack. To do this first, you need to understand how the other team’s offense is thinking. In cybersecurity, this is done through penetration (pen) testing, which aims to find network flaws that attackers could exploit in the future.

Considering that today’s complex cybersecurity environment harbors threats that emerge regularly, we have to face the fact that we face a large number of vulnerabilities.

See Also: Ensure Your Organization’s Security With Credential-Based Vulnerability Assessment

By developing mature cybersecurity solutions and ensuring they work to their full potential, organizations should be proactive in implementing a penetration testing program alongside vulnerability management programs.

Once an organization understands that there is a requirement for these programs to be implemented, it should perform an internal penetration test. Internal penetration tests should comprehensively describe all known vulnerabilities and the necessary actions an organization needs to close them.

Internal Penetration Test

An internal penetration test is equivalent to an external penetration test, but there are fewer variables and testing choices in an internal penetration test. While external pen tests allow organizations to test the black, white, or gray-box methodology, internal pen-testing lacks such flexibility.

The black-box testing methodology requires the attacker to have little knowledge of the organization’s current security structure. Still, since an internal employee performs the internal pen testing, it is impossible not to know the network architecture before testing.

Because the simulation of an internal pen test scenario is done when an attacker is found on the organization’s network, it can holistically test vulnerabilities, passwords, network configurations, and internal monitoring checks all at once.

An internal pen test requires a cybersecurity engineer to connect to the organization’s internal network and access sensitive corporate resources through an internal network connection. This test is a real scenario that often happens in organizations where a malicious actor gains a foothold on an internal entity and exploits it. This malicious person could be a current or former employee or an external entity that acquired internal server login credentials through a current employee’s negligence.

An internal pen test is conducted inside the building access or host protection framework, while an external test simulates an attack on an entity over the internet. Although both aim to remove possible vulnerabilities, an external pen test focuses on an intrusion that originates from beyond the company’s firewall. An internal pen test is performed from within the confines of the firewall.

Due to the on-site measurable closed-loop attack, the attacker makes a coordinated effort to access unauthorized resources. This requires the support staff’s role to document the progress of the attacker and monitor vulnerabilities that exist within the organization.

After the attacker connects to an active network port from inside the internal network, they must locate specific network authentication credentials that grant them administrative access. This essentially unlocks all doors to their advantage. Since they do not have a firewall to pass through, the attack can be carried out much faster, giving the attacker more time to exploit any vulnerabilities, if any.

Internal attacks are particularly dangerous because they enable the attacker to have extensive insider knowledge of where and how the coveted files are stored on the network. This is a luxury that external aggressors often did not know from the very beginning of their exploitation campaigns.

Internal Penetration Test Checklist

Whether it’s a malicious insider or a negligent employee who exposes your organization to a phishing attack, organizations should consider evaluating their cybersecurity efforts from the perspective of an attacker who has already gained access to the internal network.

To perform an internal pen test that ensures your company is protected from internal threats, the specific sequence of events that your organization must comply with are as follows:

Preparation Phase

First, plan the team’s technical touchpoints to use before, during, and after the test initiation. Your organization should select the in-house person to be on duty during testing to ensure that all responsibilities maintained under testing are met.

Once the person on duty has been identified, a compatible team should be assigned. The readiness of these teams allows your organization to establish an effective communication line during a security assessment.

Once the team is structured, it should be detailed how the testing scope and goals align with the priority business objectives. If part of the assessment is not covered, it will burden your budget and your team’s time. Once the scope is defined, your organization must also decide what approvals and access control it needs to obtain for the pentester before the test can be run.

The next step is to form a formal approval agreement with the pentester, which must be signed before the pencil test can be done. Since internal pen testing is essentially an imitation of a cyber-attack, it is best to get everything expected in writing for a formal agreement to ensure everyone is on the same page.

This last part of the preparation process requires agreement between the pentester and senior staff outlining which parts of the organization’s systems will be tested and prohibited.

Identify Vulnerabilities

Upon commencement of the internal pen testing, the pentester will first use the tool to search for all existing vulnerabilities. From this point on, Pentester will examine internal IT systems for any weaknesses that could be used to compromise the network’s integrity.

With the access gained by penetration testers in a secure system, advanced techniques and analysis are used to measure the magnitude of the damages that each vulnerability can cause. The source of each vulnerability is monitored by software that allows the organization to address each vulnerability after testing.

Exploitation Phase

Internal pen tests are preferred for organizations that want to mimic an actual attacker’s actions using weaknesses in network security without experiencing the effects of permanent abuse. As the attack techniques used by cybercriminals evolve, the internal pen test becomes to have exploitation methods.

The exploit task is used to identify potential weaknesses in a cybersecurity program for the IT team to fix after testing. In these real-life scenarios, sensitive data is often stolen, often related to research documents, company financial information, or customers’ payment information.

Penetration testers are tasked with simulating a genuine internal attack that obtains sensitive data and company information and covers traces to prevent the company from learning that it initiated the breach.

Reporting Phase

As a result, an internal pen test will reveal significant risks to network infrastructure. Upon completing the internal pen testing, the pentester and security team should report their findings to senior personnel and possibly their management or stakeholders and establish a plan to address these vulnerabilities.

The final report will assess the organization’s network’s overall health and provide suggestions on how to combat a malicious attacker who performed a series of maneuvers during testing. These reports are written to prioritize the solutions needed to fix the security flaws that have been found.

Protection against Internal Threats

With most of today’s cybercriminals using internal methods to infiltrate organizations, companies need to be proactive in their approach to fixing vulnerabilities long before a malicious attacker exploits them.

The use of security measures inside and outside allows the organization to have a defense-in-depth approach to information security and eliminate blind spots and vulnerabilities.

The built-in pen test also aims to test the Intrusion Detection System and the employee’s response to the detection of an intruder in the network. While malicious employees are a potential incident to your organization, it is still essential to keep your critical internal systems safe if they get lost.

Regardless of the source of the attacker, their motives and methods are varied. Therefore, security teams should be aware of all vulnerabilities in employee authentication to access sensitive company information used as attack vectors.

Most of today’s cyberattacks are unlike external threats; they are more like internal users who access systems and services abnormally. Unless security teams focus on network security controls, they risk compromising their systems with phishing techniques to access sensitive systems under the radar.

The organization can plan a response against any hacking attempt using the information obtained from the security assessment. Internal item tests can check for misconfigurations, such as errors in error handling, allowing employees to access online information, and accidentally leak information. Because user privacy and data security are paramount, it is recommended that you also perform internal penetration tests as often as your organization performs external pen tests.

What are the Prerequisites for Internal Network Penetration Test?

Understand the Business Requirements. If you had a better understanding of why penetration testing is necessary, it would be helpful. It’s best if you determine if your internal penetration test would be application-oriented or compliance-oriented. Job requirements will dictate how the remainder of the task will be approached.

Define the Scope. Describe what is covered and what is expressly excluded. Besides, the rules of engagement should have a clear definition of what is and is not allowed.

Examine Past Threats and Vulnerabilities. Although reviewing what was previously learned in a penetration test is usually a good idea, it is also required by PCI requirement 11.3. This analysis helps you to concentrate on previously identified bugs to ensure that the same problems are resolved or do not recur.

Get Authorization. Actions are taken during a penetration test usually are considered illegal if done without prior consent. As long as you do not sign your paperwork, legal danger can await you.

Agree on the timing. There may be certain times when the risk of intervention or downtime is considered a higher outcome in an organization, such as periods of high usage or periods of project implementations and upgrades. So make sure you agree on an acceptable time frame for performing the internal penetration test.

Define source IPs to whitelist. The penetration test’s target organization should be informed of the source IPs from which you will perform the test. There are several reasons for this, but to properly perform a penetration test without a WAF or IPS intervention, you must request that your source IPs be whitelisted on such devices.

Confirm existing internal contacts. During the penetration test, it is essential that you agree on a communication plan and who will be available on-site. Not only is this a good idea to get them to support you through the testing process, but it is also a good idea to immediately notify the target organization if a “Critical” vulnerability is discovered.

  • Make sure you do everything within the discussed and agreed scope.
  • Make sure you sign an authorization to perform the penetration test.
  • Never perform an internal or external penetration test without prior approval.
  • Do not test outside the agreed test scope.

How Should Internal Penetration Test Method Be?

It is essential to follow an industry methodology as a basis for internal penetration testing. You can also create your processes and procedures to test on industry methodology.

Surkay Baykarahttps://www.pcidssguide.com
A passionate Senior Information Security Consultant working at Cyberwise. Over the past 15+ years my professional career has included several positions beginning as a developer and IT administrator, working my way up to a senior Technical Performance Consultant before joining Biznet back in 2015. I had several different roles at Cyberwise, including Penetration Tester and PCI DSS QSA. In my job as a QSA, I found my passion and worked closely with the Audit and Compliance team. I've been working inside InfoSec for over 15 years, coming from a highly technical background. I have earned several certifications during my professional career including; CEH, CISA, CISSP, and PCI QSA.

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