Ravi Sir's Cyber Security Cards › Revision Cards
Service Versions, OS Detection and NSE Scripts
Service Versions, OS Detection and NSE Scripts Nmap can find the version of each service and guess the operating system. NSE = the Nmap Scripting Engine, extra scripts for deeper checks. nmap -sV target shows: 21/tcp open ftp vsftpd 2.3.4 . That gives port, service and exact version to look up. The
Read card text
What this card says
What it is
Nmap can find the version of each service and guess the operating system.
NSE = the Nmap Scripting Engine, extra scripts for deeper checks.
Example
nmap -sV target shows: 21/tcp open ftp vsftpd 2.3.4.
That gives port, service and exact version to look up.
Why it matters for security
The version tells you which known bugs may apply.
Some NSE scripts are safe; some are intrusive. Use intrusive ones only in your lab.
| Category | What it does | Safe on the lab? |
|---|---|---|
| default | Useful, fast, low-risk scripts (-sC) | Yes |
| safe | Will not crash services | Yes |
| discovery | Extra information (SMB shares, HTTP titles...) | Yes |
| vuln | Checks for known vulnerabilities | Lab only |
| auth / brute | Tests credentials | Lab only – can lock accounts |
Learn more in the lesson: 19.7 Service Versions, OS Detection and NSE Scripts