Beyond the Firewall: Unmasking Hidden Threats Through Internal Network Penetration Testing

The protection of sensitive data and critical infrastructure is paramount for an organization to operate smoothly. As organizations depend on internal networks to facilitate their daily operations, the security of these networks becomes a vital concern. While firewalls and other defensive measures stand as the first line of defense, they alone cannot guarantee impenetrability. This is where internal network penetration testing, often referred to as “Internal Pentesting,” comes into play.

In the notable Twitter (currently ‘X’) breach of 2020, adversaries successfully gained unauthorized access to the accounts of prominent individuals such as Barack Obama, Elon Musk, Bill Gates, Jeff Bezos, and Michael Bloomberg, as well as high-profile companies like Apple and Uber. This breach had far-reaching consequences, causing stock prices to plummet by up to 4 percent. Additionally, in 2023, a significant security incident unfolded when Mailchimp, a widely used email marketing platform, saw the compromise of around 100 high-profile user accounts.

It is crucial to note that both these breaches were initiated through phishing attacks on employees, enabling unauthorized access to the internal network. Twitter confirmed that the attackers had exploited this access to Twitter’s administrative tools, allowing them to manipulate accounts and post tweets directly. This serves as a reminder of the critical need for organizations to bolster their defenses against social engineering tactics and strengthen their internal network security to safeguard against such malicious intrusion using internal network pentesting. Read on to learn more about what internal network pentesting is, its importance, and more.

What is Internal Network Penetration Testing

Internal network penetration testing is a security assessment process that concentrates on identifying vulnerabilities and weaknesses within an organization’s internal network infrastructure. In contrast to external network penetration testing, which emulates attacks originating from outside the network perimeter, internal penetration testing evaluates the security posture from within the organization’s boundaries.

Internal vs. External Network Penetration Testing

Comparing internal and external network penetration testing reveals distinct technical approaches. External network testing concentrates on evaluating the security of public-facing assets—like websites, mail servers, and cloud apps—to uncover vulnerabilities exploitable by external threats. Techniques include vulnerability scanning, port analysis, and web app testing, aimed at identifying weaknesses attackers could target from outside the network. The objective is to gauge the effectiveness of perimeter defenses against attacks.

Conversely, internal network testing replicates attacks initiated from within, mimicking the actions of insiders or compromised accounts. This evaluation assesses internal security measures and potential lateral movement within the network post breach. Testers focus on activities like privilege escalation, lateral traversal, and data exfiltration. This approach uncovers concealed vulnerabilities and strengthens defense strategies, ensuring the resilience of internal systems even if perimeter defenses falter.

Both internal and external pentest approach uncovers hidden vulnerabilities and strengthens the organization’s defense strategies.

Common Vulnerabilities Discovered in Internal Network Pentest

Given the rising costs associated with data breaches and cyberattacks each year, organizations must remain increasingly vigilant. Adversaries employ a variety of tactics to breach systems, and one of their primary strategies is to exploit common vulnerabilities that are many times left unpatched.

Following are some of the common vulnerabilities that should be patched to avoid breaches from internal networks.

• Weak Authentication: Identifying weak passwords, default credentials, and inadequate authentication practices that may result in unauthorized access to systems and sensitive data.
• Privilege Escalation: Attempting to escalate privileges to gain unauthorized access to critical systems or sensitive information beyond authorized levels.
• Lateral Movement: After initial access, testers explore lateral movement within the network, seeking to access other systems or sensitive data.
• Misconfigured Services: Searching for misconfigurations in network services and applications, including improperly configured firewalls, routers, switches, and other network devices.
• Outdated Software: Identifying unpatched or outdated software with known vulnerabilities that attackers could exploit and assessing the associated risks.
• Insecure Network Protocols: Analyzing network traffic for insecure protocols like cleartext authentication or weak encryption that can expose sensitive data to interception.
• Data Leakage: Checking for potential data leakage points where sensitive information might be inadvertently exposed or transmitted without proper encryption.
• Unrestricted Access to Sensitive Data: Reviewing file permissions and access controls to ensure only authorized personnel can access sensitive data.
• Insufficient Segmentation: Assessing the effectiveness of network segmentation measures, as inadequate segmentation can allow attackers to move freely across the network.
• Privileged Accounts and Service Accounts: Evaluating the management of privileged and service accounts, including password management, access control, and auditing.
• Malware and Persistence: Searching for signs of malware presence and persistence mechanisms that enable attackers to maintain access even after an initial compromise.
• Social Engineering: Assessing the human factor in security by performing social engineering tests, such as phishing attacks or attempts to gain unauthorized physical access.
• Unauthorized Wireless Access Points: Detecting rogue wireless access points that may provide unauthorized entry points into the network.
• Shadow IT and Unapproved Devices: Checking for unauthorized or unapproved devices connected to the network, including personal laptops or unauthorized IoT devices.

The results of internal network penetration testing help organizations identify and prioritize security weaknesses, enhance their security controls, and improve their overall security posture. Regular testing is crucial for proactively addressing vulnerabilities and reducing the risk of internal threats.

Remember, network pentesting requires proper authorization and adherence to the defined scope to prevent unintended consequences.

The Importance of Internal Network Penetration Testing

Engaging in internal network penetration testing represents a proactive cybersecurity strategy that organizations should prioritize for the following reasons.

Identifying Vulnerabilities

By simulating attacks from an internal perspective like white box pentesting, vulnerabilities that might otherwise go unnoticed can be exposed. This includes outdated software, cloud misconfigurations, and insecure coding practices.

Mitigating Risks

Identifying vulnerabilities before malicious actors do allows organizations to address these issues promptly, reducing the risks associated with successful cyber attacks and advanced persistent threats.

Regulatory Compliance

Many industries have regulatory requirements, like HIPAA, PCI DSS, and GDPR, mandating regular pentesting and vulnerability scanning, including penetration tests. This helps ensure that data protection regulations and privacy standards are upheld by the organization. It’s essential to emphasize that non-compliance can lead to substantial fines and potentially damage the organization’s reputation among both partners and consumers.

Enhancing Defense Strategies

Insights gained from internal penetration tests can inform the refinement of security measures, leading to a more robust and effective defense strategy.

Challenges and Ethical Considerations in Internal Network Penetration Testing

Internal network penetration testing presents a series of challenges and ethical considerations to organizations. Central to the process is the precise definition of the test’s scope, which holds the key to avoiding unintended disruptions and impact on production systems. Striking the right balance between a comprehensive assessment and minimal operational disturbances requires a careful approach to delineating the scope by upholding the CIA triad i.e., by maintaining confidentiality, integrity, and availability in the process.

Another critical facet lies in accurately interpreting the test results. Dealing with false positives, instances where nonexistent vulnerabilities are flagged, and false negatives, the overlooking of actual vulnerabilities, demands nuanced analysis.

Moreover, the importance of legal compliance and explicit consent cannot be overstated. To avert legal ramifications, obtaining the necessary permissions from relevant stakeholders before initiating the penetration test is a prerequisite. This not only fulfills legal requirements but also adheres to ethical principles by ensuring transparency and accountability.

Lastly, handling sensitive data encountered during the assessment is of utmost significance. Maintaining the highest level of care by data protection regulations underscores the ethical integrity of the testing process. For instance, in healthcare organizations, it’s imperative to ensure that patient data or protected health information (PHI) is never used during penetration testing.

By skillfully navigating these challenges and ethical considerations, organizations demonstrate their commitment to robust cybersecurity practices while upholding ethical standards.

About BreachLock

BreachLock is a global leader in PTaaS and penetration testing services. BreachLock offers human-delivered, AI-powered solutions integrated into a single platform based on a standardized built-in framework that enables consistent and regular benchmarks of attack tactics, techniques, and procedures (TTPs), security controls, and processes to deliver enhanced predictability, consistency, and accurate results in real-time, every time.
Schedule a discovery call with our certified pentesting experts to kickstart your next Internal pentest in just one business day.