How to analyze FTP services with NMAP?

NMAP (Network Mapper) is a potent open source tool used for network security auditing, network discovery, and service enumeration. One of its uses is to analyze File Transfer Protocol (FTP) services.

To analyze FTP services with NMAP, you first need to understand the basics of the NMAP command line and its key components. Here are samples:

```
nmap -p 21 —script ftp-anon,ftp-bounce,ftp-proftpd-backdoor,ftp-vsftpd-backdoor,ftp-vuln-cve2010-4221
```

1. `nmap` – It’s the command to start NMAP.
2. `-p 21` – It tells NMAP to only scan port 21, which is the default FTP port.
3. `—script` – It allows specifying a script from NMAP scripting engine to better customize the scan.
4. `` – It’s the IP address or the domain of the host you’re scanning.

This command scans port 21 using specific scripts namely `ftp-anon`, `ftp-bounce`, `ftp-proftpd-backdoor`, `ftp-vsftpd-backdoor`, and `ftp-vuln-cve2010-4221` in the NMAP Scripting Engine (NSE), which will analyze the FTP services running on the target for any security vulnerabilities (Source: “NMAP Network Scanning: The Official NMAP Project Guide to Network Discovery and Security Scanning”, Lyon).

If you want to better comprehend the interpretation of the results, under NMAP’s output, look for service banners (source: “NMAP 6: Network Exploration and Security Auditing Cookbook”, Fyodor). For instance, vsFTPd 2.3.4 signifies the FTP service running on the target machine is of version 2.3.4. This information can help you understand the potential vulnerabilities of the FTP service that you’re analyzing.

For more comprehensive results, you may implement multiple NMAP scripts. For instance, ‘ftp-brute’ can be used for brute forcing FTP login credentials.

The NMAP scripting engine harnesses various scripts, each designed to perform specialized tasks. For a thorough analysis of an FTP service, it’s prudent to use a suitable set of scripts (source: “Mastering the NMAP Scripting Engine”, Paulino Calderon).

Before running any scans, it’s essential to familiarize yourself with the underlying laws and ethics. Unauthorized scanning can be tantamount to illegal actions (source: “Hacker’s Challenge 3”, Bill Pennington).

To sum up, NMAP is a powerful tool that can help you analyze FTP services. By using specific commands and interpreting the outcomes correctly, you can unearth potential vulnerabilities or unusual behaviors in an FTP service.

References:
1. Lyon, G. F. (2008). NMAP Network Scanning: The Official NMAP Project Guide to Network Discovery and Security Scanning.
2. Fyodor (2012). NMAP 6: Network Exploration and Security Auditing Cookbook.
3. Paulino Calderon (2015). Mastering the NMAP Scripting Engine.
4. Bill Pennington, David Pollino, et al. (2006). Hacker’s Challenge 3: 20 Brand-New Forensic Scenarios & Solutions.