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What Is Penetration Testing? Types, Methodologies, Compliance & CI/CD (2025 Guide)

API Security

Shreya Srivastava

Dec 1, 2023

Introduction

(Protecting Your Systems from Hackers)

Imagine the internet as a vast network of connected devices, each a potential target for cyberattacks. These attacks can cause widespread damage, steal data, disrupt operations, or even hold systems hostage. To prepare for these threats, security teams conduct a simulated attack called penetration testing, or pen testing for short. This involves testing their systems for weaknesses that hackers could exploit. It's like a security drill, helping organisations identify and fix problems before they become real disasters.

What is Penetration Testing?

Penetration testing, also known as pen testing, is a security exercise where a cybersecurity expert tries to find and exploit weaknesses in a computer system or network. This is done to identify and fix security flaws before malicious actors can exploit them. Think of it like a practice drill for your security defences.

Penetration testing isn’t one-size-fits-all. Beyond access models (black/white/gray box), teams scope by asset: Web & mobile apps, APIs, cloud (IaaS/PaaS/SaaS), networks (internal/external), wireless, and people/process via social engineering. Each target class surfaces different risks (e.g., BOLA in APIs, misconfig in cloud, auth flaws in web) and often requires different tooling and reporting depth. Map scope to real business risk and data sensitivity first, then choose the asset types to test.

Example - 'A retail chain hires a pen tester to test the security of its point-of-sale (POS) systems. The pen tester discovers that the POS systems are vulnerable to a malware attack that could steal credit card information from customers. The retail chain implements security measures to protect its POS systems and customer data.'

Checkout GPT-5 vs O3 vs GPT-4.1, Which one is better for Penetration Testing

Compliance: Where Pen Testing Fits

Penetration testing supports regulatory obligations by validating that controls actually work. Some frameworks explicitly require periodic pen tests—e.g., PCI DSS v4.0 requires organizations processing card data to conduct penetration tests—while others (HIPAA, GDPR, ISO 27001) use pen testing as a way to evidence due diligence and control effectiveness. Add the relevant citation and cadence to your security program so audits don’t stall.

Tools You’ll See in a Typical Engagement

Common toolchains combine recon/scanning (Nmap), traffic analysis (Wireshark/tcpdump), web/API testing (Burp Suite, OWASP ZAP), and exploit frameworks (Metasploit). Many testers work from Kali Linux, which bundles these utilities for faster workflows. Tool choice depends on scope and rules of engagement; the report should link each critical finding to the tools and techniques used.

How Often Should You Pen Test?

Run a full-scope pen test at least annually (or semiannually for high-risk environments), plus after major releases, architecture changes, or new internet-facing assets. Between full tests, use targeted mini-engagements for new APIs, cloud accounts, or critical services, and maintain continuous vulnerability management. Tie cadence to risk: the more change velocity and data sensitivity, the more frequently you test.

Benefits of penetration testing:

Identify and fix security weaknesses.
Reduce the risk of cyberattacks.
Improve compliance with industry regulations

Types of penetration testing:

Black-box testing: The pen tester has no prior knowledge of the system they are testing.
White-box testing: The pen tester has access to all of the information about the system they are testing.
Gray-box testing: The pen tester has some information about the system they are testing, but not all.

(Protecting Your Systems from Hackers)

What is Penetration Testing?

Checkout GPT-5 vs O3 vs GPT-4.1, Which one is better for Penetration Testing

Compliance: Where Pen Testing Fits

Tools You’ll See in a Typical Engagement

How Often Should You Pen Test?

Benefits of penetration testing:

Identify and fix security weaknesses.
Reduce the risk of cyberattacks.
Improve compliance with industry regulations

Types of penetration testing:

Black-box testing: The pen tester has no prior knowledge of the system they are testing.
White-box testing: The pen tester has access to all of the information about the system they are testing.
Gray-box testing: The pen tester has some information about the system they are testing, but not all.

(Protecting Your Systems from Hackers)

What is Penetration Testing?

Checkout GPT-5 vs O3 vs GPT-4.1, Which one is better for Penetration Testing

Compliance: Where Pen Testing Fits

Tools You’ll See in a Typical Engagement

How Often Should You Pen Test?

Benefits of penetration testing:

Identify and fix security weaknesses.
Reduce the risk of cyberattacks.
Improve compliance with industry regulations

Types of penetration testing:

Black-box testing: The pen tester has no prior knowledge of the system they are testing.
White-box testing: The pen tester has access to all of the information about the system they are testing.
Gray-box testing: The pen tester has some information about the system they are testing, but not all.

Penetration Testing Process

Planning: The pen tester gathers information about the system, defines the scope of the test, and identifies assets that are off-limits.
Reconnaissance: The pen tester gathers more information about the system, such as IP addresses, open ports, and running services.
Vulnerability scanning: The pen tester uses automated tools to scan the system for vulnerabilities, identifying known weaknesses in software, hardware, and the network.
Exploitation: The pen tester attempts to exploit the vulnerabilities they have identified.
Post-exploitation: The pen tester gathers evidence of their exploits and assesses the impact of the vulnerabilities. They provide a report outlining their findings and recommendations for remediation.

Planning: The pen tester gathers information about the system, defines the scope of the test, and identifies assets that are off-limits.
Reconnaissance: The pen tester gathers more information about the system, such as IP addresses, open ports, and running services.
Vulnerability scanning: The pen tester uses automated tools to scan the system for vulnerabilities, identifying known weaknesses in software, hardware, and the network.
Exploitation: The pen tester attempts to exploit the vulnerabilities they have identified.
Post-exploitation: The pen tester gathers evidence of their exploits and assesses the impact of the vulnerabilities. They provide a report outlining their findings and recommendations for remediation.

Planning: The pen tester gathers information about the system, defines the scope of the test, and identifies assets that are off-limits.
Reconnaissance: The pen tester gathers more information about the system, such as IP addresses, open ports, and running services.
Vulnerability scanning: The pen tester uses automated tools to scan the system for vulnerabilities, identifying known weaknesses in software, hardware, and the network.
Exploitation: The pen tester attempts to exploit the vulnerabilities they have identified.
Post-exploitation: The pen tester gathers evidence of their exploits and assesses the impact of the vulnerabilities. They provide a report outlining their findings and recommendations for remediation.

Recognized Methodologies & Standards

To keep tests consistent and auditable, align with a known standard: PTES (Penetration Testing Execution Standard) for end-to-end workflow, NIST SP 800-115 for planning & techniques, and OWASP guidelines for application & API layers. Use these as your test plan backbone and reference them in the report’s methodology section to improve credibility with auditors and engineering teams.

Penetration testing and vulnerability scanning

Penetration testing and vulnerability scanning are both important tools for improving cybersecurity, but they serve different purposes.

Vulnerability scanning is an automated process that identifies known vulnerabilities in a system. It is a good way to get a quick overview of the security posture of a system, but it does not provide a comprehensive assessment of the system's security.

Penetration testing is a manual process that involves trying to exploit vulnerabilities in a system. It is a more thorough way to assess the security of a system, but it is also more time-consuming and expensive.

The key differences between penetration testing and vulnerability scanning:

Both are essential but not interchangeable: scanners find potential weaknesses; pen tests show what an attacker can actually do.

Topic	Vulnerability Scanning	Penetration Testing
Purpose	Identify known issues quickly	Validate impact via exploitation
Method	Automated, signatures/heuristics	Manual + automated, attacker-style
Output	Lists of CVEs & misconfigs	Exploit paths, business impact, proof
Cadence	Frequent (daily/weekly)	Periodic (quarterly/semiannual or after major change)

Pen tests go deeper and reduce false positives by exploiting findings; organizations typically run both for full coverage.

Vulnerability scanning should be used regularly to get a quick overview of the security posture of a system. It is also a good way to identify vulnerabilities that can be easily exploited.

Penetration testing should be used periodically to get a more comprehensive assessment of the security of a system. It is also a good way to identify vulnerabilities that are not easily found by automated scanners.

Scope & Rules of Engagement

Use this pre-engagement checklist to avoid scope creep and legal gray areas:

In scope: domains, IP ranges, APIs, cloud accounts, mobile apps, third-party services.
Out of scope: production data exfiltration, DDoS, phishing (unless approved), lateral movement in certain networks.
Access model: black/white/gray box; credentials provided? test accounts?
Windows: dates/time, rate limits, change freezes.
Data handling: PII in logs, redaction, evidence retention.
Success criteria: impact demonstration (e.g., unauthorized data access), proof-of-exploit format, retest window.

Recognized Methodologies & Standards

Penetration testing and vulnerability scanning

Penetration testing and vulnerability scanning are both important tools for improving cybersecurity, but they serve different purposes.

The key differences between penetration testing and vulnerability scanning:

Both are essential but not interchangeable: scanners find potential weaknesses; pen tests show what an attacker can actually do.

Topic	Vulnerability Scanning	Penetration Testing
Purpose	Identify known issues quickly	Validate impact via exploitation
Method	Automated, signatures/heuristics	Manual + automated, attacker-style
Output	Lists of CVEs & misconfigs	Exploit paths, business impact, proof
Cadence	Frequent (daily/weekly)	Periodic (quarterly/semiannual or after major change)

Scope & Rules of Engagement

Use this pre-engagement checklist to avoid scope creep and legal gray areas:

In scope: domains, IP ranges, APIs, cloud accounts, mobile apps, third-party services.
Out of scope: production data exfiltration, DDoS, phishing (unless approved), lateral movement in certain networks.
Access model: black/white/gray box; credentials provided? test accounts?
Windows: dates/time, rate limits, change freezes.
Data handling: PII in logs, redaction, evidence retention.
Success criteria: impact demonstration (e.g., unauthorized data access), proof-of-exploit format, retest window.

Recognized Methodologies & Standards

Penetration testing and vulnerability scanning

Penetration testing and vulnerability scanning are both important tools for improving cybersecurity, but they serve different purposes.

The key differences between penetration testing and vulnerability scanning:

Both are essential but not interchangeable: scanners find potential weaknesses; pen tests show what an attacker can actually do.

Topic	Vulnerability Scanning	Penetration Testing
Purpose	Identify known issues quickly	Validate impact via exploitation
Method	Automated, signatures/heuristics	Manual + automated, attacker-style
Output	Lists of CVEs & misconfigs	Exploit paths, business impact, proof
Cadence	Frequent (daily/weekly)	Periodic (quarterly/semiannual or after major change)

Scope & Rules of Engagement

Use this pre-engagement checklist to avoid scope creep and legal gray areas:

In scope: domains, IP ranges, APIs, cloud accounts, mobile apps, third-party services.
Out of scope: production data exfiltration, DDoS, phishing (unless approved), lateral movement in certain networks.
Access model: black/white/gray box; credentials provided? test accounts?
Windows: dates/time, rate limits, change freezes.
Data handling: PII in logs, redaction, evidence retention.
Success criteria: impact demonstration (e.g., unauthorized data access), proof-of-exploit format, retest window.

Phase 1: Planning and Reconnaissance
- Define scope: Determine the systems to be tested and the types of tests to be conducted (black-box, white-box, or gray-box).
- Gather information: Use publicly available sources (e.g., social media, job postings) and internal sources (e.g., network diagrams, documentation) to gather information about the target system.
- Identify attack vectors: Analyze the gathered information to identify potential attack vectors, such as open ports, vulnerable software, and social engineering opportunities.
Phase 2: Scanning and Vulnerability Assessment
- Network scanning: Use network scanners to identify open ports, running services, and other network vulnerabilities.
- Vulnerability scanning: Use vulnerability scanners to identify known vulnerabilities in the target system's software, hardware, and firmware.
- Manual vulnerability assessment: Perform manual testing to validate the findings of the automated scans and identify any additional vulnerabilities that may not be detected by automated tools.
Phase 3: Exploitation
- Select vulnerabilities to exploit: Prioritize the vulnerabilities based on their severity and exploitability.
- Develop exploits: Develop or utilize existing exploits to exploit the selected vulnerabilities.
- Document exploits: Document the exploits and the steps taken to execute them.
Phase 4: Post-exploitation
- Gather evidence: Gather evidence of the exploits, such as screenshots and logs.
- Assess impact: Assess the impact of the exploits on the target system.
- Recommend remediation: Recommend remediation measures to address the exploited vulnerabilities.
Phase 5: Reporting and Remediation
- Prepare a report: Prepare a comprehensive report documenting the findings of the penetration test, including the identified vulnerabilities, exploits, and remediation recommendations.
- Present findings: Present the findings to the organization's stakeholders, such as the IT team and management.
- Remediate vulnerabilities: Collaborate with the IT team to remediate the identified vulnerabilities.

CI/CD: Add a Lightweight DAST Gate (GitHub Actions example)

Add a DAST smoke test to every PR to catch obvious issues early, then schedule weekly deeper scans. Example (GitHub Actions + OWASP ZAP Baseline):

name: zap-baseline
on:
  pull_request:
  schedule:
    - cron: '0 3 * * 1'   # weekly
jobs:
  zap:
    runs-on: ubuntu-latest
    steps:
      - name: ZAP Baseline Scan
        uses: zaproxy/action-baseline@v0.10.0
        with:
          target: ${{ secrets.ZAP_TARGET_URL }}   # e.g., https://staging.example.com
          rules_file_name: '.zap/rules.tsv'       # allowlist/deprioritize noise
          cmd_options: '-a'                       # auto config

Pair this with periodic manual pen tests for real-world exploitation coverage.

What “Good” Looks Like

A strong report opens with an executive summary (business impact, risk trends), then delivers finding-by-finding detail: description, affected assets/endpoints, reproduction steps, exploit evidence, risk rating & CVSS, and precise remediation with code/config deltas. Include a methodology section referencing PTES/NIST/OWASP and a retest results appendix. This format lets leadership prioritize quickly while giving engineers actionable fixes.

Red Team, Pen Test, and Purple Team—When to Use Each

Pen tests validate technical weaknesses in scoped assets. Red teaming simulates real adversaries across people, process, and tech, often without prior notice. Purple teaming blends attacker and defender: testers and the SOC work side-by-side to improve detections and response during the exercise. For maturing programs, add periodic purple team sessions to turn findings into measurable detection coverage.

Phase 1: Planning and Reconnaissance
- Define scope: Determine the systems to be tested and the types of tests to be conducted (black-box, white-box, or gray-box).
- Gather information: Use publicly available sources (e.g., social media, job postings) and internal sources (e.g., network diagrams, documentation) to gather information about the target system.
- Identify attack vectors: Analyze the gathered information to identify potential attack vectors, such as open ports, vulnerable software, and social engineering opportunities.
Phase 2: Scanning and Vulnerability Assessment
- Network scanning: Use network scanners to identify open ports, running services, and other network vulnerabilities.
- Vulnerability scanning: Use vulnerability scanners to identify known vulnerabilities in the target system's software, hardware, and firmware.
- Manual vulnerability assessment: Perform manual testing to validate the findings of the automated scans and identify any additional vulnerabilities that may not be detected by automated tools.
Phase 3: Exploitation
- Select vulnerabilities to exploit: Prioritize the vulnerabilities based on their severity and exploitability.
- Develop exploits: Develop or utilize existing exploits to exploit the selected vulnerabilities.
- Document exploits: Document the exploits and the steps taken to execute them.
Phase 4: Post-exploitation
- Gather evidence: Gather evidence of the exploits, such as screenshots and logs.
- Assess impact: Assess the impact of the exploits on the target system.
- Recommend remediation: Recommend remediation measures to address the exploited vulnerabilities.
Phase 5: Reporting and Remediation
- Prepare a report: Prepare a comprehensive report documenting the findings of the penetration test, including the identified vulnerabilities, exploits, and remediation recommendations.
- Present findings: Present the findings to the organization's stakeholders, such as the IT team and management.
- Remediate vulnerabilities: Collaborate with the IT team to remediate the identified vulnerabilities.

CI/CD: Add a Lightweight DAST Gate (GitHub Actions example)

Add a DAST smoke test to every PR to catch obvious issues early, then schedule weekly deeper scans. Example (GitHub Actions + OWASP ZAP Baseline):

name: zap-baseline
on:
  pull_request:
  schedule:
    - cron: '0 3 * * 1'   # weekly
jobs:
  zap:
    runs-on: ubuntu-latest
    steps:
      - name: ZAP Baseline Scan
        uses: zaproxy/action-baseline@v0.10.0
        with:
          target: ${{ secrets.ZAP_TARGET_URL }}   # e.g., https://staging.example.com
          rules_file_name: '.zap/rules.tsv'       # allowlist/deprioritize noise
          cmd_options: '-a'                       # auto config

Pair this with periodic manual pen tests for real-world exploitation coverage.

What “Good” Looks Like

Red Team, Pen Test, and Purple Team—When to Use Each

Phase 1: Planning and Reconnaissance
- Define scope: Determine the systems to be tested and the types of tests to be conducted (black-box, white-box, or gray-box).
- Gather information: Use publicly available sources (e.g., social media, job postings) and internal sources (e.g., network diagrams, documentation) to gather information about the target system.
- Identify attack vectors: Analyze the gathered information to identify potential attack vectors, such as open ports, vulnerable software, and social engineering opportunities.
Phase 2: Scanning and Vulnerability Assessment
- Network scanning: Use network scanners to identify open ports, running services, and other network vulnerabilities.
- Vulnerability scanning: Use vulnerability scanners to identify known vulnerabilities in the target system's software, hardware, and firmware.
- Manual vulnerability assessment: Perform manual testing to validate the findings of the automated scans and identify any additional vulnerabilities that may not be detected by automated tools.
Phase 3: Exploitation
- Select vulnerabilities to exploit: Prioritize the vulnerabilities based on their severity and exploitability.
- Develop exploits: Develop or utilize existing exploits to exploit the selected vulnerabilities.
- Document exploits: Document the exploits and the steps taken to execute them.
Phase 4: Post-exploitation
- Gather evidence: Gather evidence of the exploits, such as screenshots and logs.
- Assess impact: Assess the impact of the exploits on the target system.
- Recommend remediation: Recommend remediation measures to address the exploited vulnerabilities.
Phase 5: Reporting and Remediation
- Prepare a report: Prepare a comprehensive report documenting the findings of the penetration test, including the identified vulnerabilities, exploits, and remediation recommendations.
- Present findings: Present the findings to the organization's stakeholders, such as the IT team and management.
- Remediate vulnerabilities: Collaborate with the IT team to remediate the identified vulnerabilities.

CI/CD: Add a Lightweight DAST Gate (GitHub Actions example)

Add a DAST smoke test to every PR to catch obvious issues early, then schedule weekly deeper scans. Example (GitHub Actions + OWASP ZAP Baseline):

name: zap-baseline
on:
  pull_request:
  schedule:
    - cron: '0 3 * * 1'   # weekly
jobs:
  zap:
    runs-on: ubuntu-latest
    steps:
      - name: ZAP Baseline Scan
        uses: zaproxy/action-baseline@v0.10.0
        with:
          target: ${{ secrets.ZAP_TARGET_URL }}   # e.g., https://staging.example.com
          rules_file_name: '.zap/rules.tsv'       # allowlist/deprioritize noise
          cmd_options: '-a'                       # auto config