What is Penetration Testing?
Penetration testing, or pen testing, is an authorized simulated cyberattack performed to evaluate the security of a system. It goes beyond vulnerability scanning by actually exploiting weaknesses to demonstrate real-world impact.
A well-executed penetration test answers critical questions:
Can an attacker breach our defenses?
What data could they access?
How long could they remain undetected?
What's the business impact of a successful attack?
Types of Penetration Tests
By Knowledge Level
Black Box Testing
No prior knowledge of the target
Simulates external attacker perspective
Most realistic but time-consuming
Best for: External network assessments, red team exercises
White Box Testing
Full system knowledge provided
Architecture diagrams, source code access
Most thorough coverage
Best for: Application security assessments, compliance testing
Gray Box Testing
Partial information (user credentials, network diagrams)
Balances realism with efficiency
Most common approach
Best for: Internal network assessments, web application testing
By Target
Network Penetration Testing
External: Internet-facing infrastructure
Internal: Assumes breach or insider threat
Wireless: Wi-Fi networks and protocols
Web Application Testing
OWASP Top 10 vulnerabilities
Business logic flaws
Authentication/authorization issues
API security
Mobile Application Testing
iOS and Android applications
Client-side security
API communication security
Data storage practices
Social Engineering
Phishing campaigns
Vishing (voice phishing)
Physical security testing
The Five Phases of Penetration Testing
Phase 1: Planning and Reconnaissance
Objectives:
Define scope and rules of engagement
Gather intelligence about the target
Identify potential attack vectors
Planning activities:
1Scope definition
In-scope IP ranges and domains
Excluded systems (production databases, etc.)
Testing window and notification procedures
Emergency contacts
2Rules of engagement
Testing methods allowed/prohibited
Data handling requirements
Communication protocols
Stop conditions
Passive reconnaissance techniques:
OSINT gathering (Maltego, Recon-ng)
DNS enumeration (dig, dnsenum)
WHOIS lookups
Search engine dorking
Social media analysis
Job posting analysis (reveals technology stack)
Tools for passive recon:
# DNS enumeration
dig any target.com
dnsenum target.com
# Subdomain discovery
amass enum -d target.com
subfinder -d target.com
# Email harvesting
theHarvester -d target.com -b google,linkedin
# Technology fingerprinting
whatweb target.com
wappalyzer (browser extension)Active reconnaissance:
Port scanning (with authorization)
Service enumeration
OS fingerprinting
Web crawling
Phase 2: Scanning and Enumeration
Objectives:
Identify live hosts and open ports
Enumerate services and versions
Discover potential vulnerabilities
Network scanning methodology:
1Host discovery
# Ping sweep
nmap -sn 192.168.1.0/24
# ARP scan (local network)
arp-scan -l
# TCP SYN ping
nmap -PS22,80,443 192.168.1.0/242Port scanning
# Quick scan
nmap -F target.com
# Full port scan
nmap -p- -T4 target.com
# Service version detection
nmap -sV -sC -p 22,80,443 target.com
# UDP scan (slow but important)
nmap -sU --top-ports 100 target.com3Service enumeration
# SMB enumeration
enum4linux -a target.com
smbclient -L //target.com
# SNMP enumeration
snmpwalk -v2c -c public target.com
# LDAP enumeration
ldapsearch -x -h target.com -b "dc=target,dc=com"
# Web enumeration
gobuster dir -u http://target.com -w /path/to/wordlist
nikto -h target.comVulnerability scanning:
Nessus, OpenVAS, or Qualys for network vulnerabilities
Burp Suite or OWASP ZAP for web applications
Prioritize based on exploitability and impact
Phase 3: Exploitation
Objectives:
Validate vulnerabilities through exploitation
Gain initial access to systems
Document successful attack paths
Important principles:
Always work within scope
Document every action
Use the minimum necessary exploitation
Have rollback plans
Common exploitation techniques:
1Credential attacks
# Password spraying
crackmapexec smb target.com -u users.txt -p 'Spring2024!'
# Hash cracking
hashcat -m 1000 hashes.txt rockyou.txt
# Kerberoasting
GetUserSPNs.py domain/user:password -dc-ip DC_IP -request2Web application attacks
# SQL injection
sqlmap -u "http://target.com/page?id=1" --dbs
# Command injection testing
; whoami
| whoami
`whoami`
$(whoami)
# File inclusion
../../../etc/passwd
....//....//....//etc/passwd3Network attacks
# Man-in-the-middle
responder -I eth0 -wrf
# Pass-the-hash
psexec.py -hashes :NTLM_HASH [email protected]
# Relay attacks
ntlmrelayx.py -tf targets.txt -smb2supportExploitation frameworks:
Metasploit Framework - Comprehensive exploitation platform
Cobalt Strike - Commercial red team platform
Custom scripts - For specific vulnerabilities
Phase 4: Post-Exploitation
Objectives:
Maintain access for continued testing
Escalate privileges
Move laterally through the network
Identify sensitive data
Privilege escalation:
Linux privilege escalation checklist:
Kernel exploits (searchsploit linux kernel)
SUID/SGID binaries
Sudo misconfigurations
Cron jobs running as root
World-writable files in PATH
Docker/container escapes
# Automated enumeration
./linpeas.sh
./linux-exploit-suggester.sh
# Manual checks
sudo -l
find / -perm -4000 2>/dev/null
cat /etc/crontabWindows privilege escalation checklist:
Unquoted service paths
Weak service permissions
Always Install Elevated
Token impersonation
Credential harvesting
UAC bypass
# Automated enumeration
./winPEAS.exe
PowerUp.ps1
# Manual checks
whoami /priv
wmic service get name,pathname
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\InstallerLateral movement:
Pass-the-hash / Pass-the-ticket
Remote services (WMI, WinRM, PSExec)
SSH key reuse
Token impersonation
Kerberos attacks (Golden/Silver tickets)
Data exfiltration testing:
Identify sensitive data locations
Test data loss prevention controls
Document what data could be accessed
Phase 5: Reporting
Objectives:
Document all findings clearly
Provide actionable remediation guidance
Communicate risk to stakeholders
Report structure:
1Executive Summary
Overall risk rating
Key findings summary (3-5 critical points)
Business impact assessment
Recommended immediate actions
2Scope and Methodology
Systems tested
Testing approach
Tools used
Timeline
3Findings
For each vulnerability:
Title and severity (CVSS score)
Affected systems
Technical description
Proof of concept
Business impact
Remediation steps
References
4Attack Narrative
Step-by-step attack chain
Screenshots and evidence
Time taken for each phase
5Remediation Roadmap
Prioritized action items
Quick wins vs. long-term fixes
Resource estimates
Severity ratings (CVSS-based):
Critical (9.0-10.0): Immediate action required
High (7.0-8.9): Address within 30 days
Medium (4.0-6.9): Address within 90 days
Low (0.1-3.9): Address as resources allow
Informational: Best practice recommendations
Professional Standards and Ethics
Penetration Testing Standards
PTES (Penetration Testing Execution Standard)
OWASP Testing Guide
NIST SP 800-115
CREST methodology
Ethical Guidelines
Always obtain written authorization
Stay within defined scope
Protect discovered data
Report all findings honestly
Don't disrupt business operations
Maintain confidentiality
Legal Considerations
Written authorization is mandatory
Understand applicable laws (CFAA in US)
International testing requires local legal review
Data protection regulations apply
Building Your Penetration Testing Lab
Essential lab components:
Virtualization platform (VMware, VirtualBox)
Vulnerable VMs (DVWA, Metasploitable, HackTheBox)
Kali Linux or Parrot Security
Windows Server and Client VMs
Network simulation tools
Practice platforms:
HackTheBox
TryHackMe
PentesterLab
VulnHub
OWASP WebGoat
Conclusion
Professional penetration testing requires methodology, skill, and ethics. It's an essential component of any security program, providing real-world validation of your defenses.
The key is not just finding vulnerabilities, but providing actionable guidance that helps organizations improve their security posture.
Asfaleia-Tech offers comprehensive penetration testing services across network, application, and cloud environments. Contact us to schedule your assessment.