Channel Your Inner Hacker By Breaking Into a System With Nothing But a Name

Have you ever wondered how an attacker could breach a system with zero inside knowledge? Without joining the ranks of Anonymous or the Lizard Squad, learning black-box penetration testing is probably the closest you’ll get to walking in their shoes. At Sekurno, we specialize in the art and science of uncovering vulnerabilities, and we’re excited to bring you into our world. black-box penetration testing Sekurno Whether you’re new to cybersecurity or a seasoned pentester, this guide has something for everyone. Beginners will find a clear, step-by-step guide to demystify the process, while experts can gain fresh perspectives and revisit foundational principles. Imagine starting with nothing more than a company’s name or domain and systematically peeling back layers to expose vulnerabilities. step-by-step guide fresh perspectives and revisit foundational principles We’ll explore the full lifecycle of black-box pentesting, from reconnaissance to reporting, showing how each phase builds on the last to expose vulnerabilities and deliver actionable results. By the end, you’ll see why black-box pentesting is more than just a technical exercise—and a strategic necessity for staying ahead of evolving threats. full lifecycle of black-box pentesting reconnaissance reporting Editor’s note: The contents of this article are for informational purposes only. Editor’s note: The contents of this article are for informational purposes only. Editor’s note: The contents of this article are for informational purposes only. Editor’s note: The contents of this article are for informational purposes only. What is Black-Box Pentesting? Black-box penetration testing is a cybersecurity technique where the tester evaluates a system's security without prior knowledge of its internal workings, such as architecture, source code, or configurations. Simulating an external attacker’s perspective, black-box pentesting provides invaluable insights into how exposed the system is to real-world threats. Testers often rely on recognized frameworks and methodologies to structure their approach. Popular options include: OWASP Web Security Testing Guide: Focuses on web applications. PTES (Penetration Testing Execution Standard): Covers end-to-end testing processes. OSSTMM (Open Source Security Testing Methodology Manual): Ensures measurable security tests. OWASP Web Security Testing Guide: Focuses on web applications. OWASP Web Security Testing Guide: Focuses on web applications. OWASP Web Security Testing Guide OWASP Web Security Testing Guide PTES (Penetration Testing Execution Standard): Covers end-to-end testing processes. PTES (Penetration Testing Execution Standard): Covers end-to-end testing processes. PTES (Penetration Testing Execution Standard) PTES OSSTMM (Open Source Security Testing Methodology Manual): Ensures measurable security tests. OSSTMM (Open Source Security Testing Methodology Manual): Ensures measurable security tests. OSSTMM (Open Source Security Testing Methodology Manual) OSSTMM The choice of methodology depends on factors such as the type of application, client requirements, and the engagement's scope. Reconnaissance Phase We always begin with the reconnaissance (recon) phase. This foundational step involves gathering as much publicly available information about the target as possible. By mimicking how a real attacker would approach the system, we identify exposed assets, discover potential entry points, and map the attack surface. There are two main types of reconnaissance in the recon phase of penetration testing: passive and active. Passive Reconnaissance Passive reconnaissance involves gathering information about a target without directly interacting with its systems. This approach minimizes the risk of detection, making it an ideal starting point for mapping a target’s surface area. By leveraging publicly accessible information, passive reconnaissance provides valuable insights while maintaining stealth. Below are examples of tools commonly used: Domain & Asset Discovery crt.sh crt.sh One powerful tool for uncovering hidden subdomains is crt.sh, a Certificate Transparency (CT) log search engine. CT logs publicly track SSL/TLS certificates issued to domains, which can reveal subdomains that were not meant to be publicly visible. crt.sh a Certificate Transparency (CT) log search engine For instance, in 2018, researchers used CT logs to uncover unintended subdomains associated with Tesla, including a staging environment potentially vulnerable to exploitation. By leveraging crt.sh, ethical hackers, researchers, and penetration testers can quickly identify misconfigured or exposed assets that could pose significant security risks, making it an essential tool in the reconnaissance phase of black-box penetration testing. uncover unintended subdomains associated with Tesla DNSDumpster DNSDumpster DNSDumpster is a powerful DNS reconnaissance tool that provides detailed information about a domain’s DNS records, such as A, MX, and TXT records, as well as associated IP addresses. This is particularly useful in mapping the attack surface during reconnaissance, identifying hidden assets, and spotting potential misconfigurations that could be exploited. Google Dorks Google Dorks Google Dorks are advanced search operators that allow testers to uncover publicly available information indexed by Google. By using operators such as site:, filetype:, intitle:, and inurl:, testers can locate sensitive files, directories, or pages related to a target organisation. site: filetype: intitle: inurl: For example, a query like site:example.com filetype:pdf can reveal publicly accessible PDF documents, while intitle:"index of" can expose directories left unprotected. Google Dorks are an incredibly effective, yet often underestimated, reconnaissance tool for identifying potential exposures during the early stages of testing. site:example.com filetype:pdf intitle:"index of" Shodan Shodan A specialized search engine for discovering internet-connected devices and services, offering unique insights into the online infrastructure of a target. Unlike traditional search engines, Shodan indexes devices such as exposed servers, IoT devices, databases, and misconfigured systems. For instance, a simple query can reveal open ports, unsecured databases, or outdated software running on public-facing systems. Its ability to filter results by IP, location, or service type makes Shodan an invaluable tool for penetration testers during the reconnaissance phase. Data Leaks Dehashed / Intelx Dehashed / Intelx These tools help identify leaked data, such as credentials or sensitive documents. Both require subscriptions for full functionality. Intelligence X indexes dark web and public internet content, breaches, and historical website data. Intelligence X Example Queries: Example Queries: email@example.com to find breaches or mentions involving the email address. example.com to discover leaked credentials or documents. email@example.com to find breaches or mentions involving the email address. email@example.com example.com to discover leaked credentials or documents. example.com Have I Been Pwned (HIBP) Have I Been Pwned (HIBP) A free online service that checks if personal data has been compromised in known data breaches. Widely used for enhancing awareness and mitigating credential-related risks. Waybackurls Waybackurls Waybackurls is a tool that retrieves archived URLs from the Wayback Machine, offering a glimpse into a target's historical web configurations. It can uncover hidden resources, outdated pages, or endpoints that may no longer be visible on the live site but could still pose a security risk. By analysing these archived URLs, testers can identify patterns, legacy vulnerabilities, or forgotten assets that might otherwise go unnoticed. Command Example: Command Example: echo "sekurno.com" | waybackurls > urls.txt echo "sekurno.com" | waybackurls > urls.txt Active Reconnaissance Active reconnaissance involves direct interaction with a target’s systems to gather detailed information. While this approach provides precise and actionable insights for penetration testing or attack planning, it carries a higher risk of detection, as target systems may log or alert on suspicious activity. It is essential for identifying vulnerabilities and understanding the technical details of a target’s infrastructure. Subdomain Enumeration Subdomain Enumeration Identifying subdomains is a critical step in penetration testing, as subdomains often host services or applications that may be vulnerable or misconfigured. Subdomains may also provide entry points like admin panels or APIs that are not immediately visible. Sublist3r Sublist3r Is a widely-used open-source tool for subdomain enumeration. It aggregates data from multiple sources, including search engines, DNS records, and APIs, to identify subdomains linked to a target domain. Its ability to query platforms like Google, Bing, and VirusTotal makes it a reliable option for quickly mapping an organisation's external attack surface. Command Example: Command Example: python3 sublist3r.py -d sekurno.com python3 sublist3r.py -d sekurno.com Service Discovery After identifying subdomains, uncover open ports, services, and operating systems using tools like dig and Nmap. This step helps map the target’s attack surface. dig Nmap dig (Domain Information Groper) dig (Domain Information Groper) A command-line tool used to query DNS records. It provides detailed information about a domain’s DNS setup, including A, MX, TXT, CNAME, and NS records. dig is a staple in network troubleshooting and reconnaissance, allowing testers to verify configurations, identify misconfigurations, and gather insights about a domain’s infrastructure. Its speed and precision make it a go-to tool for DNS analysis. dig Command Example: Command Example: dig sekurno.com dig sekurno.com Nmap Nmap A versatile tool for network discovery and auditing. Nmap identifies open ports, services, and operating systems, providing critical insights into a target’s attack surface. Basic Scan: Basic Scan: nmap nmap Port Scanning: Port Scanning: nmap -p -sV nmap -p -sV Aggressive Scan: Combines OS detection, service detection, and scripting Aggressive Scan: Combines OS detection, service detection, and scripting nmap -A nmap -A Directory and File Discovery Directory and File Discovery Uncovering hidden pages, configuration files, and admin panels can provide critical insights for penetration testing. Tools like Dirb, Gobuster, and ffuf are commonly used. Dirb Gobuster ffuf Dirb Dirb Dirb is a web content scanner that brute-forces directories and URLs to uncover hidden or unsecured content on a web server. By using pre-configured or custom wordlists, Dirb can identify files, directories, and endpoints that might not be publicly visible but could expose sensitive information or vulnerabilities. It's a straightforward and powerful tool for mapping a web server's structure during penetration testing. Basic command for common directories: Basic command for common directories: dirb http://example.com dirb http://example.com Custom Wordlist: Custom Wordlist: dirb http://example.com /usr/share/wordlists/dirb/common.txt dirb http://example.com /usr/share/wordlists/dirb/common.txt Advanced Options: Advanced Options: dirb https://example.com -X .php,.html -N 403 dirb https://example.com -X .php,.html -N 403 Alternative Tools for Directory Enumeration Alternative Tools for Directory Enumeration Other popular tools include: Gobuster Gobuster Gobuster is a fast and efficient tool for brute-forcing URLs, directories, DNS subdomains, and more. Designed to handle large wordlists, it excels at quickly uncovering hidden resources on web servers. Gobuster supports recursive scans, making it particularly useful for exploring deeply nested directories or subdomains during penetration testing. brute-forcing URLs, directories, DNS subdomains large wordlists supports recursive scans gobuster dir -u http://example.com -w /path/to/wordlist.txt gobuster dir -u http://example.com -w /path/to/wordlist.txt ffuf (Fuzz Faster U Fool) ffuf (Fuzz Faster U Fool) A versatile and high-speed fuzzer for discovering directories, parameters, and other hidden resources on web servers. It supports advanced filtering options based on response codes, size, or words, allowing testers to efficiently pinpoint relevant results. With its flexibility, ffuf can be used for tasks like directory enumeration, parameter fuzzing, and API endpoint discovery. ffuf -u http://example.com/FUZZ -w /path/to/wordlist.txt ffuf -u http://example.com/FUZZ -w /path/to/wordlist.txt Exploring HTTP Response Headers Exploring HTTP Response Headers Finally, analyze HTTP response headers to identify software, frameworks, or server configurations in use. This step provides detailed insights but is more specific than earlier phases. Wappalyzer Wappalyzer A browser extension and tool that detects frameworks, CMS platforms, programming languages, analytics tools, and other technologies used by websites. By identifying software versions, testers can cross-reference known vulnerabilities in public databases. Scanning Scanning After reconnaissance comes the scanning phase, where testers actively analyze the target for vulnerabilities. Automated tools are essential for quickly identifying a wide range of vulnerabilities. These tools are robust, frequently updated, and tailored to evolving threats. Commonly used scanners include: scanning phase Acunetix: A web application scanner that identifies SQL injections, XSS, and other vulnerabilities. Nessus: A comprehensive vulnerability scanner for networks and systems. Nexpose: A tool for discovering and prioritizing vulnerabilities across assets. Acunetix: A web application scanner that identifies SQL injections, XSS, and other vulnerabilities. Acunetix Nessus: A comprehensive vulnerability scanner for networks and systems. Nessus Nexpose: A tool for discovering and prioritizing vulnerabilities across assets. Nexpose We primarily use Burp Suite for scanning web applications, as it offers extensive capabilities for different software frameworks and vulnerability types. Burp Suite Burp Suite Burp Suite Burp Suite is one of the most widely used tools for web application testing. It combines automated and manual capabilities, making it suitable for detecting common and advanced vulnerabilities. Key features include: Vulnerability Detection: SQL injection, XSS, command injection, directory traversal, authentication flaws, and more. API Testing: Identifies broken access controls, JSON injection, and insecure endpoints. Advanced Testing: Detects vulnerabilities like CSRF, XXE, SSRF, and parameter tampering. BApp Store Extensions: Enhances functionality with custom tools for vulnerability scanning, authorization testing, and payload generation. Vulnerability Detection: SQL injection, XSS, command injection, directory traversal, authentication flaws, and more. Vulnerability Detection: SQL injection, XSS, command injection, directory traversal, authentication flaws, and more. Vulnerability Detection API Testing: Identifies broken access controls, JSON injection, and insecure endpoints. API Testing: Identifies broken access controls, JSON injection, and insecure endpoints. API Testing Advanced Testing: Detects vulnerabilities like CSRF, XXE, SSRF, and parameter tampering. Advanced Testing: Detects vulnerabilities like CSRF, XXE, SSRF, and parameter tampering. Advanced Testing BApp Store Extensions: Enhances functionality with custom tools for vulnerability scanning, authorization testing, and payload generation. BApp Store Extensions: Enhances functionality with custom tools for vulnerability scanning, authorization testing, and payload generation. BApp Store Extensions Popular Burp Extensions Overview Popular Burp Extensions Overview AuthMatrix - Manages and tests authorization logic for multiple users or roles. Logger++ - Provides detailed logging for HTTP requests and responses. Hackvertor - Converts data formats (e.g., encoding/decoding) and automates payload transformations. Active Scan++ - Enhances Burp’s active scanner with additional checks. JS Beautifier - Beautifies/minifies JavaScript files for easier analysis. Param Miner - Finds hidden parameters in web applications. Retire.js - Detects outdated JavaScript libraries with known vulnerabilities. Burp Bounty - Customizes scans with user-defined payloads and match conditions. JSON Web Token (JWT) Editor - Manipulates and tests JWTs for vulnerabilities like signature tampering. Autorize - Automates authorization bypass testing by replaying requests with different roles AuthMatrix - Manages and tests authorization logic for multiple users or roles. AuthMatrix - Logger++ - Provides detailed logging for HTTP requests and responses. Logger++ - Hackvertor - Converts data formats (e.g., encoding/decoding) and automates payload transformations. Hackvertor - Active Scan++ - Enhances Burp’s active scanner with additional checks. Active Scan++ - JS Beautifier - Beautifies/minifies JavaScript files for easier analysis. JS Beautifier - Param Miner - Finds hidden parameters in web applications. Param Miner - Retire.js - Detects outdated JavaScript libraries with known vulnerabilities. Retire.js - Burp Bounty - Customizes scans with user-defined payloads and match conditions. Burp Bounty - JSON Web Token (JWT) Editor - Manipulates and tests JWTs for vulnerabilities like signature tampering. JSON Web Token (JWT) Editor - Autorize - Automates authorization bypass testing by replaying requests with different roles Autorize - Testssl Testssl For testing SSL/TLS configurations, we use testssl.sh, an open-source command-line tool. It assesses: testssl.sh testssl.sh Weak or deprecated protocols (e.g., SSLv2, SSLv3, TLS 1.0). Misconfigured certificates (e.g., self-signed, expired). Vulnerabilities like Heartbleed, BEAST, or POODLE. Missing HTTPS configurations, such as HSTS headers. Weak or deprecated protocols (e.g., SSLv2, SSLv3, TLS 1.0). Weak or deprecated protocols (e.g., SSLv2, SSLv3, TLS 1.0). Misconfigured certificates (e.g., self-signed, expired). Misconfigured certificates (e.g., self-signed, expired). Vulnerabilities like Heartbleed, BEAST, or POODLE. Vulnerabilities like Heartbleed, BEAST, or POODLE. Missing HTTPS configurations, such as HSTS headers. Missing HTTPS configurations, such as HSTS headers. Command Example: Command Example: [testssl.sh](http://testssl.sh) [testssl.sh](http://testssl.sh) Vulnerability Identification Vulnerability Identification Once the reconnaissance phase is complete, we move to the vulnerability identification stage. This phase involves analyzing collected data to identify security weaknesses such as misconfigurations, outdated software, or weak credentials. By combining automated scanning tools with manual probing, we can pinpoint vulnerabilities that could be exploited in real-world scenarios. vulnerability identification OWASP Web Security Testing Guide (WSTG) OWASP Web Security Testing Guide (WSTG) The OWASP WSTG is a comprehensive resource that provides structured methodologies for testing web application security. It ensures systematic and thorough assessments by guiding testers through common vulnerability tests, such as: OWASP WSTG SQL Injection: Testing input fields for exploitable SQL queries. Session Management Flaws: Evaluating mechanisms like session timeout and secure cookie handling. Authentication Issues: Checking for weak credentials and improper multi-factor authentication implementations. SQL Injection: Testing input fields for exploitable SQL queries. SQL Injection Session Management Flaws: Evaluating mechanisms like session timeout and secure cookie handling. Session Management Flaws Authentication Issues: Checking for weak credentials and improper multi-factor authentication implementations. Authentication Issues By adhering to the WSTG, testers ensure consistency and depth in their vulnerability identification process. Example: Keycloak Vulnerability Analysis Example: Keycloak Vulnerability Analysis During one engagement, we discovered that a web server was running an outdated version of Keycloak: "version": "23.0.4". Further analysis revealed that this version was affected by multiple known vulnerabilities (CVEs), including: Keycloak "version": "23.0.4" CVE-2024-1132 CVE-2023-6484 CVE-2024-1249 CVE-2023-0657 CVE-2024-2419 CVE-2023-6717 CVE-2023-6544 CVE-2023-3597 CVE-2024-1132 CVE-2024-1132 CVE-2023-6484 CVE-2023-6484 CVE-2024-1249 CVE-2024-1249 CVE-2023-0657 CVE-2023-0657 CVE-2024-2419 CVE-2024-2419 CVE-2023-6717 CVE-2023-6717 CVE-2023-6544 CVE-2023-6544 CVE-2023-3597 CVE-2023-3597 Potential Exploits Identified Potential Exploits Identified Through our analysis, we determined that attackers could leverage these vulnerabilities to: Access sensitive URLs via Path Traversal. Inject malicious content into logs through Improper Input Validation. Cause DDoS Attacks using Origin Validation Error. Gain unauthorized access by exploiting an Authentication Bypass. Steal tokens and impersonate users via Open Redirect. Execute arbitrary JavaScript with Cross-site Scripting (XSS). Register unauthorized clients through Authorization Bypass. Bypass multifactor authentication due to Missing Critical Steps in the authentication flow. Access sensitive URLs via Path Traversal. Path Traversal Inject malicious content into logs through Improper Input Validation. Improper Input Validation Cause DDoS Attacks using Origin Validation Error. DDoS Attacks Gain unauthorized access by exploiting an Authentication Bypass. Authentication Bypass Steal tokens and impersonate users via Open Redirect. Open Redirect Execute arbitrary JavaScript with Cross-site Scripting (XSS). Cross-site Scripting (XSS) Register unauthorized clients through Authorization Bypass. Authorization Bypass Bypass multifactor authentication due to Missing Critical Steps in the authentication flow. Missing Critical Steps Exploitation Exploitation The fourth step, exploitation, involves using the findings from the vulnerability identification phase to simulate real-world attacks. This process demonstrates how an attacker could exploit vulnerabilities to compromise systems, steal data, or gain unauthorized access. Conducted in a controlled environment, exploitation provides valuable insights into the potential impact of identified vulnerabilities. exploitation Controlled Exploitation: Validating Findings Controlled Exploitation: Validating Findings Exploitation begins with testing the vulnerabilities identified in the previous phase to confirm their validity and understand their potential consequences. For example, in a recent assessment, we uncovered several public CVEs linked to an outdated version of Keycloak. Among these vulnerabilities, we successfully validated an open redirect issue. Using Burp Suite Collaborator, we demonstrated the vulnerability by testing a redirection scenario. The server’s response confirmed the exploit's validity, as shown below: open redirect Burp Suite Collaborator Real-World Impact Real-World Impact The exploitation phase highlights how vulnerabilities can be used to achieve various objectives, such as: Data Theft: Exploiting open redirects or improper access controls to steal sensitive information. Unauthorized Access: Bypassing authentication mechanisms to gain administrative privileges. System Compromise: Injecting malicious payloads to execute commands or disrupt services. Data Theft: Exploiting open redirects or improper access controls to steal sensitive information. Data Theft Unauthorized Access: Bypassing authentication mechanisms to gain administrative privileges. Unauthorized Access System Compromise: Injecting malicious payloads to execute commands or disrupt services. System Compromise Mitigation Recommendations Mitigation Recommendations Following the exploitation phase, clear remediation steps are essential to address the identified issues. In the Keycloak example, we recommended the client upgrade to the latest version of the software to patch known vulnerabilities. Important Considerations Important Considerations During exploitation, it’s common to encounter scenarios where: Not All CVEs Are Exploitable: Developers may have patched or mitigated vulnerabilities without updating the software version string, leading to false positives. Context Matters: Certain vulnerabilities may only be exploitable under specific conditions or configurations. Controlled Testing: Exploitation should be carefully executed to avoid unintentional harm to the target environment. Not All CVEs Are Exploitable: Developers may have patched or mitigated vulnerabilities without updating the software version string, leading to false positives. Not All CVEs Are Exploitable Context Matters: Certain vulnerabilities may only be exploitable under specific conditions or configurations. Context Matters Controlled Testing: Exploitation should be carefully executed to avoid unintentional harm to the target environment. Controlled Testing Reporting The final step in the pentesting lifecycle is the reporting and remediation phase. This stage consolidates all findings into a detailed report that outlines vulnerabilities, their severity, and actionable recommendations to mitigate risks. A well-crafted report bridges the gap between technical teams and stakeholders, ensuring vulnerabilities are understood and addressed effectively. reporting and remediation phase Key Elements of a Pentesting Report Key Elements of a Pentesting Report To maximize impact, reports should adhere to best practices: Categorization by Severity: Clearly classify vulnerabilities as High, Medium, or Low based on their potential impact and exploitability. Detailed Vulnerability Descriptions: Include a summary, reproduction steps, potential impact, and remediation difficulty level for each finding. Actionable Recommendations: Provide clear and implementable remediation steps to address the identified vulnerabilities. Tailored Content: Feature an executive summary for stakeholders and detailed technical sections for security teams. Categorization by Severity: Clearly classify vulnerabilities as High, Medium, or Low based on their potential impact and exploitability. Categorization by Severity Detailed Vulnerability Descriptions: Include a summary, reproduction steps, potential impact, and remediation difficulty level for each finding. Detailed Vulnerability Descriptions Actionable Recommendations: Provide clear and implementable remediation steps to address the identified vulnerabilities. Actionable Recommendations Tailored Content: Feature an executive summary for stakeholders and detailed technical sections for security teams. Tailored Content executive summary Tools for Reporting Tools for Reporting Tools like Pwndoc streamline the reporting process by offering customizable templates and ensuring consistency. Using such tools accelerates report generation and maintains professional formatting. Pwndoc For inspiration, review the Public Pentesting Reports Repository, which showcases examples of professional pentest reports. Public Pentesting Reports Repository Example: Broken Access Control Example: Broken Access Control An example of a vulnerability report for a Broken Access Control issue includes: Broken Access Control Description: Unauthorized access to sensitive endpoints. Impact: Attackers can bypass role restrictions and gain administrative privileges. Remediation: Implement proper role validation checks at both client and server levels. Description: Unauthorized access to sensitive endpoints. Description Impact: Attackers can bypass role restrictions and gain administrative privileges. Impact Remediation: Implement proper role validation checks at both client and server levels. Remediation Critical Findings and Remediation Critical Findings and Remediation For critical or high-severity vulnerabilities, such as those identified using the CVSS calculator, the report includes: CVSS calculator Comprehensive Descriptions: Detailed explanation of the issue, its exploitability, and its impact. Recommended Fixes: Steps to remediate the vulnerability effectively. Comprehensive Descriptions: Detailed explanation of the issue, its exploitability, and its impact. Comprehensive Descriptions: Detailed explanation of the issue, its exploitability, and its impact. Comprehensive Descriptions Recommended Fixes: Steps to remediate the vulnerability effectively. Recommended Fixes: Steps to remediate the vulnerability effectively. Recommended Fixes To assist developers, linking to resources like the OWASP ASVS (Application Security Verification Standard) ensures they have access to a structured framework. The ASVS provides detailed security requirements and guidelines for developing, testing, and maintaining secure applications, aligning projects with industry standards. OWASP ASVS (Application Security Verification Standard) Common Challenges in Blackbox Pentesting Blackbox pentesting offers valuable insights into an organization’s external vulnerabilities but comes with specific challenges and limitations that testers must navigate. Limitations Limitations Blackbox testing is resource-intensive and inherently limited by the tester's lack of insider knowledge about the system. Key limitations include: Missed Internal Vulnerabilities: Without access to source code or internal architecture, certain issues may remain undetected. Time Constraints: Testers often lack the time to create complex exploits to fully compromise the system. Defensive Measures: Firewalls, strict filters, and other security mechanisms may block tests and skew results. Efficiency: Limited system knowledge can lead to redundant testing or overlooked issues. Missed Internal Vulnerabilities: Without access to source code or internal architecture, certain issues may remain undetected. Missed Internal Vulnerabilities Time Constraints: Testers often lack the time to create complex exploits to fully compromise the system. Time Constraints Defensive Measures: Firewalls, strict filters, and other security mechanisms may block tests and skew results. Defensive Measures Efficiency: Limited system knowledge can lead to redundant testing or overlooked issues. Efficiency Tip: Combining blackbox testing with other approaches (e.g., greybox or white-box testing) can help mitigate these limitations. Tip: Combining blackbox testing with other approaches (e.g., greybox or white-box testing) can help mitigate these limitations. White-Box or Black-Box? White-Box or Black-Box? While black-box testing provides a valuable external perspective, it works best as part of a multi-layered testing strategy. Organizations can benefit from combining testing methodologies: White-box Testing: Involves full access to internal systems, enabling a comprehensive analysis of source code, configurations, and architecture. Black-box Testing: Simulates an attacker’s approach, validating vulnerabilities identified through white-box testing. Red Teaming: Provides an advanced assessment, simulating sophisticated and persistent threats to test both technical defences and organizational processes. White-box Testing: Involves full access to internal systems, enabling a comprehensive analysis of source code, configurations, and architecture. White-box Testing Black-box Testing: Simulates an attacker’s approach, validating vulnerabilities identified through white-box testing. Black-box Testing Red Teaming: Provides an advanced assessment, simulating sophisticated and persistent threats to test both technical defences and organizational processes. Red Teaming Pro Tip: Layered testing, incorporating both white-box and blackbox methods, ensures a thorough evaluation of internal and external vulnerabilities. Pro Tip: Layered testing, incorporating both white-box and blackbox methods, ensures a thorough evaluation of internal and external vulnerabilities. AI Challenges AI Challenges The integration of Artificial Intelligence (AI) into pentesting has transformed how vulnerabilities are identified. AI-powered tools enhance testing efficiency by automating repetitive tasks and processing large datasets. Key considerations include: Artificial Intelligence (AI) into pentesting Tools Leveraging AI: DeepExploit: Automates the exploitation of identified vulnerabilities. Shodan: Uses machine learning to map exposed devices and open ports. SpiderFoot and Recon-ng: Automate OSINT collection and data correlation. Applications of AI: Analyzing IP addresses, subdomains, and services at scale. Enhancing cloud-native environment testing, including APIs and microservices. Limitations of AI: AI tools excel in automation but lack contextual understanding and decision-making. Human expertise remains essential for interpreting results and applying them effectively. Tools Leveraging AI: DeepExploit: Automates the exploitation of identified vulnerabilities. Shodan: Uses machine learning to map exposed devices and open ports. SpiderFoot and Recon-ng: Automate OSINT collection and data correlation. Tools Leveraging AI DeepExploit: Automates the exploitation of identified vulnerabilities. Shodan: Uses machine learning to map exposed devices and open ports. SpiderFoot and Recon-ng: Automate OSINT collection and data correlation. DeepExploit: Automates the exploitation of identified vulnerabilities. DeepExploit Shodan: Uses machine learning to map exposed devices and open ports. Shodan SpiderFoot and Recon-ng: Automate OSINT collection and data correlation. SpiderFoot Recon-ng Applications of AI: Analyzing IP addresses, subdomains, and services at scale. Enhancing cloud-native environment testing, including APIs and microservices. Applications of AI Analyzing IP addresses, subdomains, and services at scale. Enhancing cloud-native environment testing, including APIs and microservices. Analyzing IP addresses, subdomains, and services at scale. Enhancing cloud-native environment testing, including APIs and microservices. Limitations of AI: AI tools excel in automation but lack contextual understanding and decision-making. Human expertise remains essential for interpreting results and applying them effectively. Limitations of AI AI tools excel in automation but lack contextual understanding and decision-making. Human expertise remains essential for interpreting results and applying them effectively. AI tools excel in automation but lack contextual understanding and decision-making. Human expertise remains essential for interpreting results and applying them effectively. Insight: Combining AI-driven tools with human testers creates a balance of efficiency and contextual insight, leading to more effective pentesting outcomes. Insight: Combining AI-driven tools with human testers creates a balance of efficiency and contextual insight, leading to more effective pentesting outcomes. Summary Summary Blackbox penetration testing is a vital approach for assessing an organization's external security posture. By simulating real-world attack scenarios, it provides insights into vulnerabilities that could be exploited by external attackers. This blog post explored the full lifecycle of blackbox pentesting, highlighting its key stages and challenges: Reconnaissance: Gathering information about the target using passive and active techniques to map the attack surface. Scanning: Employing automated tools like Burp Suite and testssl.sh to identify vulnerabilities efficiently, complemented by manual probing for complex issues. Vulnerability Identification: Analyzing findings to pinpoint weaknesses such as outdated software, misconfigurations, or weak credentials, leveraging frameworks like OWASP WSTG for systematic testing. Exploitation: Demonstrating how attackers could exploit vulnerabilities to compromise systems, ensuring findings are validated and actionable. Reporting: Delivering a comprehensive report that categorizes vulnerabilities, outlines their impact, and provides actionable recommendations for remediation. Reconnaissance: Gathering information about the target using passive and active techniques to map the attack surface. Reconnaissance: Gathering information about the target using passive and active techniques to map the attack surface. Reconnaissance Scanning: Employing automated tools like Burp Suite and testssl.sh to identify vulnerabilities efficiently, complemented by manual probing for complex issues. Scanning: Employing automated tools like Burp Suite and testssl.sh to identify vulnerabilities efficiently, complemented by manual probing for complex issues. Scanning testssl.sh Vulnerability Identification: Analyzing findings to pinpoint weaknesses such as outdated software, misconfigurations, or weak credentials, leveraging frameworks like OWASP WSTG for systematic testing. Vulnerability Identification: Analyzing findings to pinpoint weaknesses such as outdated software, misconfigurations, or weak credentials, leveraging frameworks like OWASP WSTG for systematic testing. Vulnerability Identification Exploitation: Demonstrating how attackers could exploit vulnerabilities to compromise systems, ensuring findings are validated and actionable. Exploitation: Demonstrating how attackers could exploit vulnerabilities to compromise systems, ensuring findings are validated and actionable. Exploitation Reporting: Delivering a comprehensive report that categorizes vulnerabilities, outlines their impact, and provides actionable recommendations for remediation. Reporting: Delivering a comprehensive report that categorizes vulnerabilities, outlines their impact, and provides actionable recommendations for remediation. Reporting Despite its advantages, blackbox pentesting has limitations, such as its inability to uncover certain internal vulnerabilities and the challenges posed by time constraints and defensive measures. However, combining it with methodologies like white-box testing or red teaming creates a more layered and thorough security assessment. Emerging technologies like AI are enhancing pentesting efficiency by automating tasks and analyzing vast datasets, but human expertise remains indispensable for contextual understanding and strategic decision-making. By adopting a structured approach to black-box pentesting, organizations can proactively identify and address vulnerabilities, ensuring stronger defences against external threats. At Sekurno, we deliver thorough and actionable assessments to help businesses stay resilient in the face of evolving security challenges. FAQ FAQ What is blackbox pentesting? Blackbox pentesting simulates external attacks to identify vulnerabilities in systems without prior insider knowledge. How is blackbox pentesting conducted? It involves reconnaissance, vulnerability identification, scanning, and exploitation to assess the security posture of applications and networks. How does black-box testing differ from grey-box and white-box testing? Blackbox: Simulates external attacks. Greybox: Combines external attacks with partial insider knowledge. White-box: Provides full access to internal systems for comprehensive testing. What tools are used in black-box pentesting? Common tools include Nmap, Burp Suite, Metasploit, and OSINT resources like Shodan. Why is blackbox pentesting important? It provides an attacker’s perspective, ensuring that external vulnerabilities are identified and mitigated before exploitation occurs. What is blackbox pentesting? Blackbox pentesting simulates external attacks to identify vulnerabilities in systems without prior insider knowledge. What is blackbox pentesting? What is blackbox pentesting? Blackbox pentesting simulates external attacks to identify vulnerabilities in systems without prior insider knowledge. How is blackbox pentesting conducted? It involves reconnaissance, vulnerability identification, scanning, and exploitation to assess the security posture of applications and networks. How is blackbox pentesting conducted? How is blackbox pentesting conducted? It involves reconnaissance, vulnerability identification, scanning, and exploitation to assess the security posture of applications and networks. How does black-box testing differ from grey-box and white-box testing? Blackbox: Simulates external attacks. Greybox: Combines external attacks with partial insider knowledge. White-box: Provides full access to internal systems for comprehensive testing. How does black-box testing differ from grey-box and white-box testing? How does black-box testing differ from grey-box and white-box testing? Blackbox: Simulates external attacks. Greybox: Combines external attacks with partial insider knowledge. White-box: Provides full access to internal systems for comprehensive testing. Blackbox: Simulates external attacks. Greybox: Combines external attacks with partial insider knowledge. White-box: Provides full access to internal systems for comprehensive testing. What tools are used in black-box pentesting? Common tools include Nmap, Burp Suite, Metasploit, and OSINT resources like Shodan. What tools are used in black-box pentesting? What tools are used in black-box pentesting? Common tools include Nmap, Burp Suite, Metasploit, and OSINT resources like Shodan. Nmap Burp Suite Metasploit Shodan Why is blackbox pentesting important? It provides an attacker’s perspective, ensuring that external vulnerabilities are identified and mitigated before exploitation occurs. Why is blackbox pentesting important? Why is blackbox pentesting important? It provides an attacker’s perspective, ensuring that external vulnerabilities are identified and mitigated before exploitation occurs. About the Author This article was prepared by Anastasiia Tolkachova, a Security Testing Engineer at Sekurno, and reviewed by Alex Rozhniatovskyi, co-founder and CTO of Sekurno. Anastasiia has over five years of hands-on experience in penetration testing and security assessments. She specializes in testing web applications, infrastructure (both on-premises and cloud), and mobile platforms (iOS and Android). Her expertise spans Black Box, Grey Box, and White Box methodologies, alongside proficiency in vulnerability assessments and source code security reviews. Alex has seven years of experience in development and cybersecurity. He is an AWS Open-source Contributor dedicated to advancing secure coding practices. His expertise bridges the gap between software development and security, providing valuable insights into protecting modern web applications. Anastasiia Tolkachova Anastasiia Tolkachova Sekurno Sekurno Alex Rozhniatovskyi Alex Rozhniatovskyi Sekurno. Sekurno References References Tools and Resources Tools and Resources Certificate Transparency (crt.sh) DNSDumpster 40 Google Dorks You Can Use for Various Purposes Waybackurls by tomnomnom Wayback Machine (Web Archive) Shodan DeHashed Intelx Have I Been Pwned (HIBP) Wappalyzer Sublist3r Dirb on Kali Tools Gobuster ffuf (Fuzz Faster U Fool) Nmap National Vulnerability Database (NVD) Exploit Database (Exploit-DB) CVE Mitre Acunetix Nessus Nexpose Burp BApp Store Testssl.sh Certificate Transparency (crt.sh) Certificate Transparency (crt.sh) DNSDumpster DNSDumpster 40 Google Dorks You Can Use for Various Purposes 40 Google Dorks You Can Use for Various Purposes Waybackurls by tomnomnom Waybackurls by tomnomnom Wayback Machine (Web Archive) Wayback Machine (Web Archive) Shodan Shodan DeHashed DeHashed Intelx Intelx Have I Been Pwned (HIBP) Have I Been Pwned (HIBP) Wappalyzer Wappalyzer Sublist3r Sublist3r Dirb on Kali Tools Dirb on Kali Tools Gobuster Gobuster ffuf (Fuzz Faster U Fool) ffuf (Fuzz Faster U Fool) Nmap Nmap National Vulnerability Database (NVD) National Vulnerability Database (NVD) Exploit Database (Exploit-DB) Exploit Database (Exploit-DB) CVE Mitre CVE Mitre Acunetix Acunetix Nessus Nessus Nexpose Nexpose Burp BApp Store Burp BApp Store Testssl.sh Testssl.sh Guides and Articles Guides and Articles OWASP Web Security Testing Guide (WSTG) Public Pentesting Reports Repository OWASP Application Security Verification Standard (ASVS) API Pentesting Guide by Sekurno Node.Js Application Security Guide by Sekurno OWASP Web Security Testing Guide (WSTG) OWASP Web Security Testing Guide (WSTG) Public Pentesting Reports Repository Public Pentesting Reports Repository OWASP Application Security Verification Standard (ASVS) OWASP Application Security Verification Standard (ASVS) API Pentesting Guide by Sekurno API Pentesting Guide by Sekurno Node.Js Application Security Guide by Sekurno Node.Js Application Security Guide by Sekurno