The Real Corporate Penetration Testing Process: How Companies Get Hacked Before the Hackers Do! 🚀

Hey guys, I’m sn0x — a cybersecurity researcher, bug hunter, and security enthusiast. I hold multiple certifications, including CNSP, EWPTXv2, CEH v11–12, GRC, RHCSA, and Cisco Cyber Threat Management. I’ve been ranked #1 in India and #2 globally on TryHackMe, secured #134 on Hack The Box in 2021, and even won HTB Battlegrounds twice.

But hey, this isn’t a job interview, so let’s not make it sound like a LinkedIn flex. At the end of the day, I just love hacking stuff (legally!), learning cool exploits, and sharing my knowledge. So yeah, blah blah… let’s skip the formalities and get to the fun part!

Table of Content

Pre-Engagement

Information Gathering

Vulnerability Assessment

Exploitation

Post-Exploitation

Lateral Movement

Proof-of-Concept (PoC)

Post-Engagement

Pre-Engagement

Pre-engagement is the initial stage of a penetration test, focusing on preparation, defining scope, and establishing agreements. This phase ensures clarity between the client and testers regarding expectations and legalities.

Key Components of Pre-Engagement:

1. Scoping Questionnaire — Identifies the client’s security needs and objectives.
2. Pre-Engagement Meeting — Discusses scope, methodologies, and legal requirements.
3. Kick-Off Meeting — Finalizes details before the actual test begins.

Legal and Contractual Agreements

Before proceeding, a Non-Disclosure Agreement (NDA) must be signed. Types of NDAs include:

• Unilateral NDA — One party maintains confidentiality.
• Bilateral NDA — Both parties agree to confidentiality (most common in pentesting).
• Multilateral NDA — Multiple parties commit to confidentiality, often in cooperative networks.

Authorized Personnel for Engagement

Only specific company members can authorize a penetration test, such as:

• CEO, CTO, CISO, CSO, CRO, CIO
• VP of Internal Audit, Audit Manager, Director of IT/Information Security

Required Documents

Several documents must be prepared and signed before testing:

1. NDA (After initial contact)
2. Scoping Questionnaire (Before pre-engagement meeting)
3. Scoping Document (During pre-engagement meeting)
4. Scope of Work (SoW) / Contract (During pre-engagement meeting)
5. Rules of Engagement (Before kick-off meeting)
6. Contractors Agreement (For physical assessments, before kick-off)
7. Reports (During and after testing)

Scoping Questionnaire

This document defines the scope of the test and client expectations. Key details include:

• Type of assessment (Internal/External Penetration Test, Web/App Security, Red Team, etc.)
• Number of assets (IPs, domains, subdomains, applications, roles, etc.)
• Testing approach (Black/Grey/White Box, Evasive/Non-Evasive techniques)

Pre-Engagement Meeting

This meeting ensures all details are clearly outlined, including:

• Testing goals and scope
• Methodologies (OSSTMM, OWASP, vulnerability assessment techniques)
• Time estimation and attack windows
• Third-party involvement and required permissions
• Risks, scope limitations, and compliance requirements
• Contact information and communication channels
• Reporting structure and deliverables

Final Considerations

• Legal review of documents is advised.
• Third-party permissions (e.g., cloud providers) must be obtained in writing.
• Risk assessment and scope restrictions should be explicitly defined to prevent operational disruptions.

A well-structured pre-engagement phase ensures a smooth and legally compliant penetration test while aligning client expectations with testing objectives.

Information Gathering

Once the pre-engagement phase is complete, penetration testers begin the information gathering phase, a crucial step in identifying vulnerabilities. This phase helps understand the company’s infrastructure, employees, and organization, forming the foundation for further exploitation.

Key Categories of Information Gathering:

1. Open-Source Intelligence (OSINT) — Uses publicly available sources (social media, job postings, GitHub, etc.) to collect sensitive information like credentials, SSH keys, and internal dependencies.
2. Infrastructure Enumeration — Maps servers, hosts, and security measures (firewalls, WAFs) to understand the company’s attack surface.
3. Service Enumeration — Identifies running services and their versions, helping detect outdated or vulnerable applications.
4. Host Enumeration — Examines each host’s OS, services, and security configurations, revealing misconfigurations or outdated software.

Pillaging & Post-Exploitation

After gaining access to a target, pillaging involves collecting sensitive data (user credentials, internal documents, customer data) for privilege escalation or lateral movement within the network.

Vulnerability Assessment

Understanding Vulnerability Assessment

Vulnerability assessment is a key phase in penetration testing, where we analyze the information gathered earlier to find security weaknesses. This process helps identify potential risks, their causes, and their impact on the system.

Analyzing vulnerabilities is not just about listing them — it’s about understanding how they work, how they could be exploited, and how to prevent them. However, this can be complex since different factors affect security over time (past, present, and future).

Types of Analysis in Vulnerability Assessment

These analysis methods help us form logical conclusions about vulnerabilities. However, each conclusion must be verified through further testing.

Example: Identifying a Suspicious Open Port

Imagine we find TCP port 2121 open during scanning. What should we do next?

1. Is TCP connection-oriented? → Yes.
2. Is this a standard port? → No, standard ports are between 0–1023.
3. Does 2121 resemble a well-known port? → Yes, it looks similar to FTP (port 21).

Based on this, we can test if it’s a disguised FTP service using tools like Netcat or an FTP client. If the connection takes longer than usual, it might have security measures like scan delay. Running Nmap with the --min-rtt-timeout flag can help confirm this.

Vulnerability Research and Analysis

Once a vulnerability is suspected, we must research it thoroughly. This involves checking for known exploits and security weaknesses using sources like:

• CVE Details
• Exploit DB
• Vulners
• Packet Storm Security
• NIST Database

After identifying a possible vulnerability, we analyze its root cause and test Proof-of-Concept (PoC) exploits. Real-world environments often require modifying exploit code to work correctly.

Assessing Attack Paths

Next, we predict how a hacker might use the vulnerability to break into the system. This step is crucial for stealthy testing — we replicate the target system in a controlled environment to:

• Test attacks safely without triggering alarms.
• Analyze misconfigurations before real-world testing.
• Ensure we don’t accidentally crash critical services.

Revisiting Information Gathering

If no exploitable vulnerabilities are found, we go back to gathering more information. In real-world penetration testing, information gathering and vulnerability assessment often overlap — it’s an ongoing process rather than a one-time step.

Exploitation

Once vulnerabilities have been identified in the Vulnerability Assessment phase, the next step in penetration testing is Exploitation. This is where security professionals attempt to leverage discovered weaknesses to gain unauthorized access, escalate privileges, or achieve other objectives, such as data extraction or persistence within the target system.

A successful exploitation phase bridges the gap between theoretical vulnerabilities and real-world attack scenarios, demonstrating the true risk posed by security flaws.

Understanding the Exploitation Process

Exploitation is not just about running an exploit script — it requires careful preparation, testing, and execution to avoid detection and minimize unintended system disruption. The process involves:

1. Choosing the Right Exploit — Matching known vulnerabilities with available exploits.
2. Modifying Proof-of-Concept (PoC) Code — Adapting the exploit to ensure it works within the target’s environment.
3. Executing the Exploit Safely — Running the exploit with minimal risk of damaging the system.
4. Gaining a Foothold — Establishing an initial presence within the system (e.g., reverse shell, web shell).
5. Escalating Privileges — Moving from a low-privilege user to an administrator/root level.

For example, if a penetration tester finds an outdated Apache web server, they might identify a Remote Code Execution (RCE) vulnerability and use an exploit to gain shell access to the system. However, this requires careful adaptation to the specific server version and configuration.

Prioritizing Attacks: What to Exploit First?

Not all vulnerabilities are equally valuable. Some may offer easier access, while others may have a higher impact if successfully exploited. The following factors help in prioritizing:

1. Probability of Success

How likely is the exploit to work? Some vulnerabilities have well-documented working exploits, while others require extensive modification and testing.

2. Complexity

How difficult is it to execute the attack? Some exploits are as simple as running a command, while others may require significant customization.

3. Probability of Damage

Does the attack pose a risk of crashing the system or corrupting data? A Denial-of-Service (DoS) attack is usually avoided unless explicitly authorized by the client.

Example: Scoring Attack Prioritization

Based on this scoring, a Remote File Inclusion (RFI) attack is a better choice because it has a higher chance of success, lower complexity, and minimal risk of damaging the system.

Preparing for an Exploit: Safe Testing

Before executing an exploit on a live system, it is often necessary to test it in a controlled environment. This ensures that:

• The exploit works as expected.
• There is no unintended system disruption.
• The exploit does not alert security mechanisms.

To do this, penetration testers often replicate the target system in a local virtual machine (VM) using the same operating system, service versions, and configurations. This allows for safe testing and modification of exploit code before deploying it on the real target.

Additionally, some exploits require custom payloads or modifications to avoid detection. For example, if the target has antivirus or endpoint protection, a penetration tester might need to encode the payload using MSFvenom or create a more stealthy attack.

When to Avoid Exploitation?

Although exploitation is a core part of penetration testing, there are cases where it is better to report a vulnerability rather than actively exploit it:

• If the exploit could cause data loss or system instability.
• If the client does not permit full exploitation in a real environment.
• If testing the exploit requires excessive modification or custom development.

In such cases, penetration testers should document the vulnerability, explain its potential impact, and provide mitigation recommendations.

Post-Exploitation

After successfully exploiting a target system, the next phase in a penetration test is Post-Exploitation. This stage is critical as it allows security professionals to gather valuable insights from a local perspective, escalate privileges, establish persistence, and exfiltrate data. The ultimate goal is to simulate an advanced attacker’s movements while assessing security controls in place.

Key Components of Post-Exploitation

• Evasive Testing
• Information Gathering
• Pillaging
• Vulnerability Assessment
• Privilege Escalation
• Persistence
• Data Exfiltration

Evasive Testing: Staying Under the Radar

Once inside the system, every action taken could trigger an alert. Skilled administrators and security monitoring tools are designed to detect abnormal behavior. Running common commands like net user or whoami could lead to detection and account suspension. In some cases, access to the compromised machine could be lost altogether. This is why evasion techniques play a crucial role in post-exploitation.

Evasive testing can be categorized into:

• Evasive — Actions designed to completely avoid detection.
• Hybrid Evasive — A combination of evasive and non-evasive techniques.
• Non-Evasive — Fully intrusive testing, often used to test security controls in-depth.

By carefully balancing these approaches, penetration testers can identify gaps in security monitoring while minimizing detection risk.

Information Gathering: A New Perspective

Post-exploitation provides a fresh opportunity to gather information from within the target network. Unlike initial reconnaissance, this stage allows access to internal network resources, configurations, and services that were previously hidden.

Some key areas to focus on include:

• Local user accounts and permissions
• Running processes and active network connections
• Internal databases and shared folders
• Logs that reveal past security incidents

Pillaging: Extracting Valuable Data

Pillaging involves analyzing the role of a compromised host in the network and extracting useful information. This process helps in lateral movement and privilege escalation by uncovering:

• Network configurations (interfaces, routing, DNS, VPN, ARP)
• Stored credentials in configuration files and password vaults
• Internal documentation containing sensitive information
• Active network shares and employee data exchanges

By reviewing policies and access controls, testers can also identify weak password policies and other security misconfigurations that could be exploited.

Persistence: Maintaining Access

Gaining access to a system is one challenge, but maintaining access is another. Persistence techniques ensure that even if a session is lost, attackers can regain entry without re-exploiting the initial vulnerability.

Common persistence techniques include:

• Creating scheduled tasks or services
• Deploying backdoors and rootkits
• Modifying startup scripts or registry keys
• Hijacking legitimate processes

Vulnerability Assessment: From an Internal Perspective

Once inside, it is important to reassess vulnerabilities from an internal point of view. Some services that appeared secure from the outside might be misconfigured or lack proper controls internally. Internal vulnerability scanning and manual testing can reveal:

• Misconfigured access controls
• Outdated software with known exploits
• Unsecured internal databases
• Weak authentication mechanisms

This stage often sets the foundation for privilege escalation.

Privilege Escalation: Unlocking Full Control

Privilege escalation is one of the most critical steps in post-exploitation. It involves gaining higher-level permissions to move freely within the network. There are two main types of privilege escalation:

• Vertical Escalation — Gaining administrative or root access on the compromised system.
• Horizontal Escalation — Accessing multiple user accounts with different levels of privileges.

Methods of privilege escalation include:

• Exploiting misconfigured services
• Dumping password hashes and cracking them
• Leveraging stored credentials or SSH keys
• Using kernel exploits to elevate permissions

Data Exfiltration: Extracting Sensitive Information

One of the key objectives of post-exploitation is determining whether sensitive data can be stolen from the organization. Companies implement security measures like Data Loss Prevention (DLP) and encryption to prevent unauthorized data transfers. A penetration test assesses whether these controls are effective.

Common targets for exfiltration include:

• Customer databases and personal information
• Financial records and internal documents
• Intellectual property and proprietary code
• Employee credentials and authentication tokens

Before performing real data exfiltration, it is advisable to confirm with the client. Many testers use dummy data to test security controls while ensuring no actual sensitive information is compromised.

Security Frameworks and Compliance

Organizations must comply with various security regulations, depending on the type of data they handle. Some of the key compliance standards include:

Type of InformationSecurity RegulationCredit Card DataPCI-DSSHealth RecordsHIPAABanking InformationGLBAGovernment DataFISMA

Security frameworks like NIST, CIS Controls, ISO, GDPR, and FedRAMP help organizations implement best practices to safeguard data.

Understanding Lateral Movement in Cybersecurity

Lateral movement is a crucial phase in an attack where an adversary, after gaining initial access, moves through a corporate network to access critical systems and data. For penetration testers, this stage helps assess how well an organization can detect and prevent unauthorized movement within its network.

Once inside, attackers don’t stop at a single compromised machine — they explore the entire network, looking for ways to escalate privileges and access sensitive information. The ultimate goal may be data theft, operational disruption, or deploying ransomware that can cripple the organization.

Key Phases of Lateral Movement

Pivoting

In most cases, an initial breach occurs on a system that is not directly useful for deeper access. Pivoting allows attackers to use this compromised system as a gateway to move further inside the network. By tunneling traffic through the exploited machine, attackers can scan, exploit, and access internal systems that were previously unreachable.

Evasive Testing

Corporate networks implement security solutions like Intrusion Detection Systems (IDS), Endpoint Detection and Response (EDR), and firewalls to prevent unauthorized access. Attackers use techniques such as encrypted tunnels, process injection, and credential masking to avoid detection while moving laterally.

Internal Reconnaissance

Once inside, attackers gather information about the network structure, active users, and running services. Unlike external scanning, this step provides an internal perspective, revealing details that may not be visible from outside the network.

Vulnerability Exploitation

Internal networks often have misconfigurations and weak permissions that attackers exploit. Examples include:

• Using stolen credentials to access shared drives, databases, or cloud services
• Exploiting outdated software with known vulnerabilities
• Leveraging misconfigured Active Directory policies to escalate privileges

Privilege Escalation & Credential Abuse

If attackers gain access to administrator or domain-level accounts, they can fully control the network. Techniques such as Pass-the-Hash, Kerberoasting, and token impersonation allow attackers to move from standard user accounts to high-privilege accounts, expanding their control.

Why Lateral Movement Matters for Corporate Security

Many companies focus on perimeter security (firewalls, VPNs) but overlook internal threats. If an attacker bypasses external defenses, weak internal security can allow rapid compromise of the entire organization. The best defense includes:

• Network Segmentation: Restricting access between different departments and systems
• Least Privilege Access: Ensuring users only have the permissions they need
• Endpoint Security: Detecting unusual behavior across devices
• Regular Penetration Testing: Identifying weaknesses before attackers do

Lateral movement is a reality in corporate environments, and understanding how attackers operate helps organizations build better defenses.

Lateral Movement in Corporate Networks

After gaining initial access to a corporate network through exploitation and privilege escalation, the next crucial step in a penetration test is Lateral Movement. This phase simulates how an attacker would navigate the internal network to expand access, compromise more systems, and exfiltrate sensitive data.

In real-world attacks, lateral movement is often used in ransomware campaigns where a single compromised machine can lead to an entire network being locked down. Organizations that lack proper security controls often realize their vulnerabilities only after a breach, leading to financial and reputational damage.

How Attackers Move Laterally

Once inside a network, an attacker follows a structured approach to expand their access:

1. Pivoting — Using a compromised system as a proxy to explore internal networks.
2. Evasion Techniques — Avoiding detection by security tools like EDR, IDS, or SIEM.
3. Internal Reconnaissance — Identifying reachable systems, services, and stored credentials.
4. Vulnerability Exploitation — Finding weaknesses within the network to escalate privileges further.
5. Credential Theft & Privilege Escalation — Using password reuse, hash cracking, or pass-the-hash techniques.

Each of these steps mimics real-world attacker tactics, making it critical for security teams to detect and mitigate them.

Pivoting — The Key to Internal Access

In most corporate networks, internal systems are isolated from external access. To reach them, attackers use pivoting — a technique where a compromised host acts as a bridge to route traffic deeper into the network. This allows access to non-routable systems that were previously unreachable.

For example, an attacker who compromises an internal workstation can route their scans through it to explore additional network segments, such as database servers or internal applications.

Evasion Techniques — Staying Undetected

Corporate networks deploy security solutions like EDR (Endpoint Detection & Response) and IDS (Intrusion Detection Systems) to detect unusual activity. Attackers counter these by:

• Living off the Land (LotL) — Using built-in tools like PowerShell and WMI instead of external malware.
• Encrypted Tunnels — Establishing covert communication channels (e.g., SSH tunnels, reverse proxies).
• Timing Attacks — Executing scans and commands in slow intervals to avoid detection.

Understanding how security solutions operate is crucial to bypassing them while moving laterally.

Internal Reconnaissance — Mapping the Network

Before attacking more systems, an attacker needs to gather intelligence. This includes:

• Identifying AD (Active Directory) assets, users, and permissions.
• Extracting stored credentials from memory or misconfigured applications.
• Scanning for open services that could be exploited.

Often, attackers find shared credentials or misconfigured permissions that allow them to take over multiple systems without even running exploits.

Exploiting Internal Vulnerabilities

Once weaknesses are identified, an attacker exploits them to gain access to additional machines. Common tactics include:

• Pass-the-Hash (PtH) — Using stolen NTLM hashes to authenticate as another user.
• Kerberoasting — Extracting service account hashes from Active Directory.
• Misconfigured Privileges — Exploiting excessive user permissions to gain administrative control.

Many organizations focus only on securing external assets, leaving internal systems vulnerable to simple privilege escalation techniques.

Post-Exploitation — Maintaining Control

After successfully moving through the network, the attacker consolidates access by:

• Extracting sensitive files and credentials.
• Establishing persistence mechanisms (e.g., scheduled tasks, registry modifications).
• Covering tracks to avoid detection.

At this point, an attacker has complete control over internal systems, and the only thing stopping them is effective network segmentation, logging, and proactive threat monitoring.

Defending Against Lateral Movement

Organizations can minimize the risk of lateral movement through:

• Network Segmentation — Restricting internal access based on roles and departments.
• Least Privilege Principle — Ensuring users only have the permissions they need.
• Monitoring & Detection — Using SIEM, anomaly detection, and active threat hunting.
• Regular Pentesting — Identifying internal weaknesses before attackers do.

Proof-of-Concept (PoC)

In penetration testing, a Proof-of-Concept (PoC) is essential for demonstrating that a discovered vulnerability is real, exploitable, and impactful. It serves as concrete evidence, proving that an attacker can take advantage of a security weakness to compromise systems.

Security teams and developers rely on PoCs to validate findings, assess risks, and determine remediation steps. Without a PoC, vulnerabilities may be dismissed as theoretical risks rather than immediate security concerns.

Why PoCs Matter in Corporate Security

In corporate environments, security teams often face pushback when reporting vulnerabilities. IT teams may argue that a weakness is “not exploitable” or “unlikely to be used in an attack.” A well-documented PoC eliminates such doubts by showing exactly how an attacker could exploit the issue, making it clear that action is required.

A PoC is not just about proving a single vulnerability — it helps organizations:

• Understand the real-world impact of a security flaw.
• Replicate the issue to validate and test remediation.
• Assess the likelihood of exploitation in a real attack.
• Prioritize security fixes based on risk and severity.

Different Forms of PoCs

A PoC can take multiple forms depending on the target environment and vulnerability type:

1. Documentation-Based PoC — A detailed report explaining the vulnerability, its root cause, and potential attack scenarios.
2. Exploit Code or Script — A working script that automates the exploitation of the vulnerability to demonstrate its impact.
3. Demonstration with Common Exploits — Executing calc.exe on a Windows system is a classic way to prove Remote Code Execution (RCE).

In penetration testing, exploit scripts are often the most convincing because they provide a repeatable method to test the vulnerability. However, they also come with risks if misused or improperly secured.

The Problem with Script-Based PoCs

While PoCs that include exploit scripts are useful, they can sometimes lead to a false sense of security within organizations.

Developers and administrators may focus only on modifying systems to block the specific script rather than fixing the underlying issue. This approach is flawed because:

• The script is just one way of exploiting the vulnerability.
• An attacker could use different methods to achieve the same result.
• Blocking a PoC script does not mean the vulnerability is patched.

For example, if a penetration tester provides a PoC script for an insecure authentication bypass, a development team might tweak their code to prevent that exact attack path. However, if they do not fully understand the underlying issue, another variation of the attack might still work.

PoCs and the Bigger Security Picture

A good PoC is more than just an exploit — it provides context and remediation guidance to help organizations address the core problem. This is where reporting plays a key role.

Penetration testers should:

• Explain how the vulnerability fits into a broader attack chain.
• Show how multiple security weaknesses can be combined for a successful attack.
• Emphasize that fixing a single flaw does not eliminate the entire risk.

For example, if an attacker gains access to a corporate network due to weak password policies, simply changing one exposed password (e.g., Password123) does not solve the root problem. The entire password policy needs to be reviewed and improved to prevent future breaches.

Effective PoC Reporting

An impactful PoC report should:

1. Clearly describe the vulnerability and how it can be exploited.
2. Provide a step-by-step breakdown of the attack scenario.
3. Include evidence (screenshots, logs, or exploit results).
4. Offer realistic remediation strategies beyond just blocking the PoC method.
5. Highlight security best practices to prevent similar vulnerabilities.

Security teams must ensure that organizations do not just fix one instance of a vulnerability but address the underlying security flaw across all affected systems.

So yeah, that’s my take on the penetration testing process. This is how it usually goes in the corporate world, but let’s be real — keep in mind that some companies may have slight variations based on their security policies and needs.

I write blogs like these to document my journey and share what I learn along the way, hoping it helps those who need it. Cybersecurity is a vast field, and there’s always something new to explore.

That’s all for now — until next time, stay curious and keep hacking (ethically, of course)!

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