Internal Network Penetration Testing Services

An Internal Network Penetration Test is a planned security check that looks at the safety of your internal systems, servers, workstations, Active Directory, cloud resources, and network setup from the viewpoint of someone who already has access to your network.

Internal testing does not focus on firewalls or internet-facing services. Instead, it reviews the controls that protect your systems after someone gets inside. This covers authentication, user privileges, network segmentation, trust relationships, endpoint security, and access to sensitive data.

The goal is not only to find vulnerabilities, but also to see if they let attackers gain more access, escalate privileges, move between systems, or compromise important assets.

• Black Box Penetration Test: Simulates an attack by an uninformed outsider, providing a realistic assessment of your network defenses.
• Gray Box Penetration Test: This test combines partial knowledge of your network with efficient security assessments, balancing the benefits of black and white box testing.
• White Box Penetration Test: This test involves complete knowledge of your network to identify deep-rooted vulnerabilities and assess internal security controls.
• Authenticated Penetration Test: Uses valid user credentials to assess security from the perspective of an authenticated user, identifying vulnerabilities from malicious insiders or attackers with stolen credentials.
• Red Team Penetration Test: Simulates an attack by an outsider, providing a comprehensive evaluation of your security defenses and incident response capabilities

Many businesses spend a lot on perimeter security and assume their internal users and systems are safe. However, attacks often prove this assumption wrong.

Cybercriminals routinely gain internal access through phishing campaigns, stolen passwords, compromised VPN accounts, supply chain attacks, malware, and cloud account compromises. Once inside, attackers often encounter weak segmentation, excessive permissions, misconfigured Active Directory environments, and poorly secured administrative accounts.

Internal penetration tests uncover weaknesses before attackers can take advantage of them. These assessments show how well your controls stand up to threats and help you understand the risks after a breach.

Each project starts by setting the scope and deciding which systems, networks, and environments will be tested. Depending on your goals, testing might start from a regular user’s workstation, a limited user account, a segmented network area, or another approved starting point.

Our consultants use both manual testing and safe exploitation to check authentication, access controls, network structure, Active Directory, user privileges, passwords, endpoints, and network segmentation.

We search for ways an attacker could escalate privileges, reach important data, or take control of key systems. When possible, we safely exploit vulnerabilities to confirm the risk and show what could happen.

After testing, you get a detailed report with executive summaries, technical findings, risk ratings, attack scenarios, recommendations for fixing issues, and advice to strengthen your security.

1. Planning and Scoping: Define the scope of the test, including which systems, servers, and networks are tested. Gather necessary information such as network diagrams, system configurations, and credentials.
2. Reconnaissance and Information Gathering: Collect additional information about the target systems through passive and active reconnaissance techniques. This step helps map the attack surface and identify potential entry points.
3. Vulnerability Identification: We use automated tools and manual techniques to identify system vulnerabilities. These tools scan for open ports, outdated software, misconfigurations, and insecure coding practices.
4. Exploitation: Attempt to exploit identified vulnerabilities to gain unauthorized access, escalate privileges, or extract sensitive data. This step helps demonstrate the vulnerabilities’ real-world impact.
5. Post-Exploitation and Analysis: Analyze the exploitation phase results to understand the compromise’s extent and potential damage an attacker could cause.
6. Reporting: Compile a detailed report outlining the vulnerabilities discovered, the methods used to exploit them, and the potential impact. The report should also include recommendations for remediation and improving the overall security posture.
7. Remediation and Re-Testing: Work with the organization to address the identified vulnerabilities and implement security improvements. Conduct follow-up testing to ensure that the remediation efforts are effective.

Most successful cyberattacks do not begin with a direct compromise of critical servers. Instead, attackers often target Active Directory because it controls user authentication, access permissions, administrative privileges, and access to sensitive business resources.

During an internal penetration test, our consultants evaluate Active Directory from the perspective of a real attacker. We identify weaknesses that could allow unauthorized access, privilege escalation, credential theft, and domain compromise.

Common Active Directory vulnerabilities we discover include excessive administrative permissions, weak service account configurations, credential reuse, insecure delegation settings, unconstrained delegation, stale privileged accounts, weak password policies, and vulnerable Group Policy configurations.

Our testing process evaluates attack techniques commonly used by ransomware groups and threat actors, including Kerberoasting, password spraying, pass-the-hash attacks, privilege escalation, lateral movement, and attack path analysis.

The objective is to identify how an attacker could move from a compromised workstation to domain administrator access and provide recommendations to reduce that risk.

Internal tests often uncover problems that external assessments miss, such as too many permissions, weak passwords, unsafe practices, exposed data, outdated systems, poor network segmentation, insecure protocols, and cloud misconfigurations.

The assessment can also reveal ways attackers might move between systems, paths for escalating privileges, weak spots in endpoint protection, and gaps in monitoring controls.

Testing is based on real-world attack methods, so it gives a clearer picture of actual risks than vulnerability scans, which only point out weaknesses.

Many regulatory frameworks and security standards require or strongly recommend penetration testing as part of a mature cybersecurity program.

Internal penetration testing can help support compliance efforts related to:

• PCI DSS
• SOC 2
• ISO 27001
• HIPAA
• CMMC
• NIST Cybersecurity Framework
• NIST 800-171

Internal testing shows how well your controls work by simulating real attack scenarios. This helps you focus on fixing the vulnerabilities that matter most to your business.

Tanner Security offers independent penetration testing services carried out by experienced consultants who know both offensive security tactics and business risk management.

Our approach combines automated analysis with thorough manual testing to find vulnerabilities, privilege escalation paths, Active Directory weaknesses, and attack scenarios that automated tools often miss.

We provide a clear plan by showing how different vulnerabilities can add up to create business risks. You get specific, practical advice to improve your security and lower the chance of a breach.

No matter if you run a single office, a large company, a healthcare facility, a financial institution, or use cloud services, our Internal Network Penetration Testing Services help you see what an attacker could do after getting into your environment.

An attacker only needs one successful entry point to begin moving through your environment. Internal network penetration testing helps you understand what happens next.

Contact Tanner Security Consultants to discuss your environment, testing objectives, and compliance requirements. Our team can help you identify weaknesses before attackers have the opportunity to exploit them.