An internal penetration test, often referred to as an “internal pentest” or “internal network security assessment,” is a controlled and authorized cyberattack simulation conducted from inside your organization’s network perimeter. Unlike an external penetration test, which focuses on public-facing assets, an internal pentest assumes either:
An assumed breach scenario: Simulating an attacker who has successfully compromised an external defense and gained initial access.
An insider threat: Mimicking the actions of a malicious employee, contractor, or a user whose account has been compromised.
The core purpose of an internal penetration test is to determine:
Lateral Movement Capabilities: How far an attacker could move horizontally across your internal network once initial access is gained.
Privilege Escalation: Whether an attacker could elevate their access from a standard user to an administrator or domain administrator.
Access to Sensitive Data: What critical data or systems an attacker could reach, exfiltrate, or compromise.
Internal Control Effectiveness: How well your internal segmentation, access controls, and monitoring systems detect and prevent unauthorized activity.
Hidden Vulnerabilities: Uncovering weaknesses that might not be visible from an external perspective, such as misconfigured internal applications, unpatched internal servers, or weak internal credentials.
This type of penetration testing is vital because, regardless of robust external security, the reality is that a significant percentage of data breaches originate or propagate from within the network, often due to social engineering, unpatched systems, or over-privileged accounts.
At Adversim, our internal penetration testing methodology is built on a foundation of industry best practices (such as the Penetration Testing Execution Standard - PTES, and OWASP) combined with deep attacker emulation tactics. We go beyond automated scans to provide a thorough, manual, and actionable assessment.
Here's a breakdown of our approach:
We begin with a detailed discussion to thoroughly understand your unique internal network environment, specific security concerns, and the critical assets you wish to protect. This crucial phase defines:
Objectives: What specific goals will the test aim to achieve (e.g., gain domain administrator access, exfiltrate mock sensitive data from a specific server, access a particular database)?
Scope: Which internal networks, IP ranges, systems, applications, and user roles are precisely in scope for the internal network assessment?
Rules of Engagement (RoE): Clear, mutually agreed-upon guidelines for permissible activities, communication protocols, emergency contacts, and the secure handling of any sensitive data discovered during the test.
Credentialing: Whether the test will be performed as a "black box" (no prior internal access/credentials provided, simulating an attacker's initial foothold) or "grey box" (with limited, non-privileged credentials provided, simulating a compromised user or insider threat).
Blog: How to Scope a Penetration Test]
Once inside the network (either via assumed breach or initial exploit), our expert penetration testers discreetly gather information about your internal landscape. This phase includes:
Network Mapping: Discovering active devices, network topology, and identifying services running on internal hosts.
Asset Discovery: Identifying servers, workstations, databases, critical applications, and their operating systems/versions.
User & Credential Enumeration: Discovering internal user accounts, groups, and potential credential patterns that could be leveraged.
Service Enumeration: Identifying running services and their versions across your internal infrastructure to pinpoint potential attack vectors.
We employ a powerful blend of industry-leading automated tools and extensive manual analysis by our human experts to pinpoint weaknesses. This phase meticulously focuses on:
Configuration Audits: Identifying misconfigurations in operating systems, applications, network devices, and security tools.
Patch Management Gaps: Discovering unpatched software versions or missing security updates that could be exploited for initial access or privilege escalation.
Weak Access Controls: Analyzing overly permissive user permissions, shared accounts, insecure administrative interfaces, or broken authentication mechanisms.
Internal Application Flaws: Thoroughly testing any internal web applications or APIs for common vulnerabilities (e.g., SQL Injection, Cross-Site Scripting (XSS), Broken Authentication, insecure direct object references).
Active Directory Weaknesses: Identifying misconfigurations, weak policies, or vulnerabilities within your Active Directory environment that could lead to widespread compromise.
This is where our team attempts to prove the exploitability of identified vulnerabilities. Our focus is always to demonstrate real-world impact without causing any disruption or damage to your live environment. This phase may involve:
Gaining Unauthorized Access: Ethically exploiting vulnerabilities to achieve initial internal access or escalate privileges.
Lateral Movement: Simulating an attacker's movement across your internal network to reach higher-value targets or other sensitive segments.
Privilege Escalation: Attempting to gain higher levels of access (e.g., from a standard user account to an administrator or domain administrator).
Persistence Establishment: Demonstrating methods an attacker could use to maintain access over time within your network.
Data Exfiltration Simulation: Proving that sensitive data could be accessed and exfiltrated from your network (always using mock data or with explicit prior consent).
Our commitment to you extends far beyond finding vulnerabilities. We provide clear, comprehensive, and genuinely actionable insights in a detailed report:
Executive Summary: A high-level overview of the findings, overall risk posture, and key strategic recommendations for your leadership team, presented in non-technical language.
Detailed Technical Findings: For each identified vulnerability, we provide a clear description, its potential impact, precise evidence/Proof of Concept (PoC) to help your team reproduce it, and specific, prioritized remediation steps.
Strategic Recommendations: Beyond immediate fixes, we offer guidance on improving your long-term internal security posture, processes, and toolsets.
Our service doesn't end with the report. We strongly recommend and offer retesting of all critical and high-severity vulnerabilities identified during the initial assessment. This validation ensures that your remediation efforts have been successful and that the vulnerabilities are truly closed, providing crucial evidence for compliance and true risk reduction.
Blog: What Happens After a Penetration Test? Remediation, Retesting, and Lessons Learned
In today's complex and evolving threat landscape, relying solely on perimeter security is an incomplete strategy. An internal penetration test offers unparalleled value, directly addressing critical risks that external assessments often cannot reveal:
Proactively identify and remediate vulnerabilities that could be exploited by malicious insiders or through accidental employee errors and misuse of privileges.
Gain confidence that your internal firewalls, VLANs, and network segmentation are truly effective at isolating sensitive data and critical systems, preventing unauthorized lateral movement post-breach.
Satisfy crucial requirements for frameworks and attestations such as SOC 2, HIPAA, PCI DSS, ISO 27001, and CMMC. Many of these regulations mandate periodic internal security assessments to demonstrate due diligence and the operating effectiveness of controls.
Pinpoint exploitable paths to your most valuable intellectual property, confidential customer data, financial records, and operational technology (OT) systems.
The findings from an internal penetration test provide your security team with real-world attack scenarios, helping them refine their detection capabilities, alerting systems, and incident response playbooks for internal breaches.
Move beyond theoretical risks to identify practical, exploitable weaknesses within your internal network, leading to a stronger, more resilient cybersecurity infrastructure that can withstand sophisticated attacks.
An internal pentest transforms a hopeful "we think we're secure internally" into a confident "we know where our internal weaknesses are and exactly how to fix them."
It simulates a cyberattack from inside your network to test exposure and identify vulnerabilities.
Even the strongest perimeter defenses can’t stop every threat. Internal testing helps identify what an attacker could exploit once inside—like unsecured file shares, outdated software, weak passwords, or domain privilege escalation paths.
External testing focuses on internet-facing systems and simulates attacks from the outside. Internal testing begins behind the firewall and mimics a threat actor already inside the network, often uncovering more critical risks.
Typically, we request either a VPN connection or a virtual machine on the internal network. No elevated privileges are needed—we test from the perspective of a compromised low-privileged user or rogue device.
We use industry-standard tools like BloodHound, CrackMapExec, Responder, Mimikatz, SharpHound, and custom scripts. Manual testing is emphasized to mimic real-world attacker behavior, not just automated scans. We use a mix of open-source and commercial tools to find security vulnerabilities and weak configurations.
No. We design our tests to be safe and non-disruptive. Exploit attempts are controlled and scoped to avoid downtime or service impact. We work with your team to schedule tests around sensitive time periods if needed.
You’ll receive a detailed report including executive summaries, technical findings, risk ratings, proof of concept data, and clear, prioritized remediation guidance. We also offer post-engagement debriefs to walk through results with stakeholders.
At minimum, annually or after major changes to your internal infrastructure (e.g., domain controller upgrades, office migrations, M&A activity). Regulated industries may require more frequent testing.
Yes, many standards require internal testing. For example, PCI DSS requires both internal and external penetration testing. HIPAA and GLBA recommend internal testing as part of a risk-based security program.
Yes. We provide step-by-step fixes and follow-up support for your security teams.
Internal network penetration testing isn’t just about security—it’s also essential for meeting compliance standards. Many industries are required to test their internal controls regularly to protect sensitive data and prove that safeguards are working. Our testing approach is aligned with leading frameworks and regulations, so you can address both technical risks and audit readiness in one engagement. Below are some of the key standards our internal penetration testing services support.
Internal network penetration testing aligns with NIST 800-53 and 800-171 by validating control effectiveness within federal or contractor networks. Since these standards emphasize risk-based assessments, internal testing ensures security controls resist insider threats. Additionally, it provides evidence for audit readiness.
Under GLBA, financial institutions must secure customer data from both external and internal threats. Consequently, internal penetration testing plays a critical role in identifying unauthorized access paths within internal systems. As a result, it helps institutions maintain consumer trust and regulatory alignment.
Internal penetration testing is especially important for HIPAA compliance, as it verifies the security of systems handling protected health information (PHI). Moreover, it identifies gaps that could expose patient records to internal misuse. Therefore, regular internal testing helps meet the Security Rule’s technical safeguards.
Internal network penetration testing supports PCI DSS compliance by uncovering vulnerabilities within cardholder data environments. Because PCI requires regular testing, this approach ensures businesses proactively reduce risk. Additionally, it helps demonstrate due diligence to assessors and supports ongoing certification efforts.
The Nevada Gaming Control Board mandates strong internal controls, which internal penetration testing directly supports. Because casinos manage sensitive patron and operational data, this testing helps ensure internal access is restricted and monitored. Moreover, it aligns with gaming regulations and audit standards.
Internal network penetration testing helps tribal casinos satisfy security expectations under IGRA and related tribal-state compacts. While the act does not mandate specific testing, regulators increasingly expect proactive security. Therefore, internal testing demonstrates good faith and supports data protection efforts.
We simulate real-world cyberattacks against your public-facing systems to uncover vulnerabilities before attackers do. This helps identify exploitable weaknesses in firewalls, VPNs, email servers, and other internet-accessible assets.
This test mimics an attacker who has gained internal access, helping uncover insecure configurations, legacy systems, and lateral movement paths. It reveals how deep an intruder could go inside your network and what data might be compromised.
We assess the security of your Wi-Fi networks, identifying risks such as rogue access points, weak encryption, and insecure configurations. The goal is to prevent unauthorized access and protect sensitive data traveling over your wireless infrastructure.
We perform in-depth testing of your web applications using both automated tools and manual techniques to uncover flaws like injection, authentication bypass, and insecure direct object references. This ensures your apps are secure against OWASP Top 10 threats.
We conduct phishing, pretexting, and baiting campaigns to measure your employees’ resistance to real-world social engineering tactics. This service helps you identify human vulnerabilities and improve security awareness training.
We evaluate your cloud-hosted infrastructure and configurations for misconfigurations, privilege escalation paths, and insecure APIs. This ensures your AWS, Azure, or GCP environments align with cloud security best practices.
e attempt to breach your physical security controls by tailgating, badge cloning, or bypassing locks to test your facility’s resilience against intruders. This reveals gaps in physical access controls, alarm systems, and visitor management.
Our red team mimics real-world adversaries using stealth, persistence, and custom tooling to test your entire security ecosystem across digital, human, and physical layers. This provides a true test of your detection, response, and resilience capabilities.
Internal network penetration testing is crucial for casinos because it identifies hidden risks within surveillance systems, gaming networks, and operations. As a result, it helps protect player data, meet gaming commission standards, and reduce internal fraud opportunities.
Since healthcare systems handle sensitive patient data, internal pen testing plays a vital role in securing internal networks. Moreover, it ensures medical devices, EHR systems, and administrative systems comply with HIPAA and resist insider threats.
Financial firms must stay ahead of sophisticated threats; therefore, internal penetration testing is essential for uncovering weaknesses in employee-accessible systems. Additionally, it helps prevent privilege abuse and strengthens internal safeguards for sensitive financial data.
Because hotels and resorts process vast guest data internally, internal penetration testing helps expose gaps in POS systems, guest apps, and property management platforms. Furthermore, it ensures data integrity, boosts resilience, and supports PCI DSS compliance.
Internal network penetration testing matters deeply in law firms, since client data often resides on internal servers. Not only does it reveal misuse risks, but it also ensures professional service firms prevent credential compromise and unauthorized file access.
For cloud and SaaS companies, internal penetration testing is necessary to safeguard the infrastructure that supports user platforms. In turn, it helps maintain secure access control, detects lateral movement opportunities, and supports a zero-trust model.
Because schools and EdTech systems contain sensitive student records, internal pen testing ensures these environments stay protected. In addition, it reveals weaknesses in learning platforms and helps institutions maintain FERPA compliance.
Internal network penetration testing is vital for retail and eCommerce brands, as it uncovers flaws in employee systems, back-office networks, and inventory controls. As a result, it not only supports PCI compliance but also defends against insider-driven data leaks.
We’ve conducted internal penetration testing for casinos, hospitals, law firms, SaaS providers, and more. Our experts think like adversaries, move like insiders, and deliver remediation reports your team can act on immediately.
Whether you need compliance validation or a real-world insider threat simulation, Adversim helps you protect what matters most.
