**WHOIS** \(pronounced as the phrase "who is"\) is a query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block or an autonomous system, but is also used for a wider range of other information. \(From [here](https://en.wikipedia.org/wiki/WHOIS)\)
**Default port:** 43
```text
PORT STATE SERVICE
43/tcp open whois?
```
## Enumerate
Get all the information that a whois service has about a domain:
```bash
whois -h <HOST> -p <PORT> "domain.tld"
echo "domain.ltd" | nc -vn <HOST><PORT>
```
Notice than sometimes when requesting for some information to a WHOIS service the database being used appears in the response:
Also, the WHOIS service always needs to use a **database** to store and extract the information. So, a possible **SQLInjection** could be present when **querying** the database from some information provided by the user. For example doing: `whois -h 10.10.10.155 -p 43 "a') or 1=1#"` you could be able to **extract all** the **information** saved in the database.
