43 - Pentesting WHOIS

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Basic Information

The WHOIS protocol serves as a standard method for inquiring about the registrants or holders of various Internet resources through specific databases. These resources encompass domain names, blocks of IP addresses, and autonomous systems, among others. Beyond these, the protocol finds application in accessing a broader spectrum of information.

Default port: 43

PORT   STATE  SERVICE
43/tcp open   whois?

Enumerate

Get all the information that a whois service has about a domain:

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.

Shodan

port:43 whois

HackTricks Automatic Commands

Protocol_Name: WHOIS    #Protocol Abbreviation if there is one.
Port_Number:  43     #Comma separated if there is more than one.
Protocol_Description: WHOIS         #Protocol Abbreviation Spelled out

Entry_1:
  Name: Notes
  Description: Notes for WHOIS
  Note: |
    The WHOIS protocol serves as a standard method for inquiring about the registrants or holders of various Internet resources through specific databases. These resources encompass domain names, blocks of IP addresses, and autonomous systems, among others. Beyond these, the protocol finds application in accessing a broader spectrum of information. 


    https://book.hacktricks.xyz/pentesting/pentesting-smtp

Entry_2:
  Name: Banner Grab
  Description: Grab WHOIS Banner
  Command: whois -h {IP} -p 43 {Domain_Name} && echo {Domain_Name} | nc -vn {IP} 43