🛠 Security Tool Cheatsheet
Sarah Chen — SOC Analyst & Tool Specialist
{
“title”: “Security Tool Cheatsheet: Nmap”,
“content”: “
What is Nmap?
Nmap (Network Mapper) is a powerful open-source tool designed for network discovery and security auditing. It is commonly used by security analysts and penetration testers to map out networks, discover hosts and services, and identify vulnerabilities.
Installation
Nmap can be installed on various platforms, including Windows, macOS, and Linux. Use the following commands for installation:
# For Ubuntu/Debian\nsudo apt install nmap\n\n# For CentOS/RHEL\nsudo yum install nmap\n\n# For macOS (using Homebrew)\nbrew install nmap\n\n# For Windows download from:\nhttps://nmap.org/download.html
Basic Syntax
The basic syntax for using Nmap is as follows:
nmap [options] [target]
Discovery
Ping Scan
To quickly check which hosts are up on a network:
nmap -sn 192.168.1.0/24
Service Version Detection
To discover what services are running on open ports:
nmap -sV 192.168.1.1
Scanning
Full TCP Scan
To perform a complete TCP scan and identify open ports:
nmap -sT 192.168.1.1
UDP Scan
To scan for open UDP ports:
nmap -sU 192.168.1.1
Exploitation
Enable OS Detection
To determine the operating system of a target:
nmap -O 192.168.1.1
Script Scanning
To use Nmap scripts to detect vulnerabilities and exploits:
nmap --script=vuln 192.168.1.1
Analysis
Output Formatting
To save scan results in various formats:
| Flag | Description |
|---|---|
| -oN | Normal output file |
| -oG | Grepable output |
| -oX | XML output |
Evasion
Fragment Packets
To evade firewalls and IDS by fragmenting packets:
nmap -f 192.168.1.1
Change Source Port
Change the source port to avoid detection:
nmap --source-port 12345 192.168.1.1
Reporting
Generate Report
To generate a comprehensive HTML report:
nmap -oX report.xml 192.168.1.1
Quick Reference Table
| Flag | Description |
|---|---|
| -sn | Ping scan |
| -sV | Service version detection |
| -sT | TCP connect scan |
| -sU | UDP scan |
| -O | OS detection |
| –script | Use scripts |
| -oN | Normal output |
| -oG | Grepable output |
| -oX | XML output |
| -f | Fragment packets |
| –source-port | Change source port |
Pro Tips
- Use
nmap -p-to scan all 65535 ports. - Combine options for advanced scanning, e.g.,
nmap -sS -sV -O 192.168.1.1.
Real-World Examples
Here are some examples of how to use Nmap effectively:
Example 1: Network Inventory
To create an inventory of all live hosts and their open ports:
nmap -sP 10.0.0.0/24 –oN nmap_live_hosts.txt\n# Use additional flags for detailed port and service discovery as needed
Example 2: Vulnerability Assessment
To find vulnerabilities using Nmap Scripting Engine:
nmap --script vuln 192.168.1.1 --script-args unsafe=1\n# Combine with port scanning flags for a more thorough check
“,
“keywords”: [“Nmap”, “network scanning”, “security tool”, “vulnerability assessment”]