hacktricks/network-services-pentesting/pentesting-rpcbind.md

111/TCP/UDP - Pentesting Portmapper

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Basic Information

Portmapper is a service that is utilized for mapping network service ports to RPC (Remote Procedure Call) program numbers. It acts as a critical component in Unix-based systems, facilitating the exchange of information between these systems. The port associated with Portmapper is frequently scanned by attackers as it can reveal valuable information. This information includes the type of Unix Operating System (OS) running and details about the services that are available on the system. Additionally, Portmapper is commonly used in conjunction with NFS (Network File System), NIS (Network Information Service), and other RPC-based services to manage network services effectively.

Default port: 111/TCP/UDP, 32771 in Oracle Solaris

PORT    STATE SERVICE
111/tcp open  rpcbind

Enumeration

rpcinfo irked.htb
nmap -sSUC -p111 192.168.10.1

Sometimes it doesn't give you any information, in other occasions you will get something like this:

Shodan

• port:111 portmap

RPCBind + NFS

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.

NIS

Exploring NIS vulnerabilities involves a two-step process, starting with the identification of the service ypbind. The cornerstone of this exploration is uncovering the NIS domain name, without which progress is halted.

The exploration journey begins with the installation of necessary packages (apt-get install nis). The subsequent step requires using ypwhich to confirm the NIS server's presence by pinging it with the domain name and server IP, ensuring these elements are anonymized for security.

The final and crucial step involves the ypcat command to extract sensitive data, particularly encrypted user passwords. These hashes, once cracked using tools like John the Ripper, reveal insights into system access and privileges.

# Install NIS tools
apt-get install nis
# Ping the NIS server to confirm its presence
ypwhich -d <domain-name> <server-ip>
# Extract user credentials
ypcat –d <domain-name> –h <server-ip> passwd.byname

NIF files

Master file	Map(s)	Notes
/etc/hosts	hosts.byname, hosts.byaddr	Contains hostnames and IP details
/etc/passwd	passwd.byname, passwd.byuid	NIS user password file
/etc/group	group.byname, group.bygid	NIS group file
/usr/lib/aliases	mail.aliases	Details mail aliases

RPC Users

If you find the rusersd service listed like this:

You could enumerate users of the box. To learn how read 1026 - Pentesting Rsusersd.

Bypass Filtered Portmapper port

When conducting a nmap scan and discovering open NFS ports with port 111 being filtered, direct exploitation of these ports is not feasible. However, by simulating a portmapper service locally and creating a tunnel from your machine to the target, exploitation becomes possible using standard tools. This technique allows for bypassing the filtered state of port 111, thus enabling access to NFS services. For detailed guidance on this method, refer to the article available at this link.

Shodan

• Portmap

Labs to practice

• Practice these techniques in the Irked HTB machine.

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HackTricks Automatic Commands

Protocol_Name: Portmapper    #Protocol Abbreviation if there is one.
Port_Number:  43     #Comma separated if there is more than one.
Protocol_Description: PM or RPCBind        #Protocol Abbreviation Spelled out

Entry_1:
  Name: Notes
  Description: Notes for PortMapper
  Note: |
    Portmapper is a service that is utilized for mapping network service ports to RPC (Remote Procedure Call) program numbers. It acts as a critical component in Unix-based systems, facilitating the exchange of information between these systems. The port associated with Portmapper is frequently scanned by attackers as it can reveal valuable information. This information includes the type of Unix Operating System (OS) running and details about the services that are available on the system. Additionally, Portmapper is commonly used in conjunction with NFS (Network File System), NIS (Network Information Service), and other RPC-based services to manage network services effectively.

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

Entry_2:
  Name: rpc info
  Description: May give netstat-type info
  Command: whois -h {IP} -p 43 {Domain_Name} && echo {Domain_Name} | nc -vn {IP} 43

Entry_3:
  Name: nmap
  Description: May give netstat-type info
  Command: nmap -sSUC -p 111 {IP}

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Support HackTricks

• Check the subscription plans!
• Join the 💬 Discord group or the telegram group or follow us on Twitter 🐦 @hacktricks_live.
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