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NFS (Network File System)

Default Port: 2049

NFS (Network File System) is a protocol that provides shared file system services on a computer network. NFS allows a server to share directories and files, which can then be mounted on client machines over the network.

NFS operates on a server-client model, where the server shares file systems and clients can use these shared files.

Connection​

Connecting to NFS Shares​

Mounting NFS shares is typically done using the mount command. For example:

mount -t nfs X.X.X.X:/path/to/share /mnt/nfs

This command mounts the share located at /path/to/share on the server with IP address X.X.X.X to the /mnt/nfs directory.

Listing NFS Shares​

The showmount command can be used to list the shares on a server:

showmount -e X.X.X.X

Enumeration​

Discovering NFS Shares​

Tools like Nmap can be used to discover NFS shares on a target host. For example:

nmap -p 2049 X.X.X.X

Exploiting NFS Shares​

Mounting NFS shares can reveal sensitive information and potentially lead to unauthorized access if proper access controls are not in place.

Attack Vectors​

Unauthorized Access to NFS Shares​

Unauthorized access to NFS shares allows an attacker to access and even modify sensitive data over the network. This poses a significant risk if proper authorization is not enforced.

Compromising NFS Servers​

Compromising an NFS server grants an attacker full access to files on the server. This enables access to sensitive data and can even be used as a pivot point to further compromise other devices on the network.

NFS Brute Force Attacks​

Brute force attacks to gain access to NFS servers are a common tactic. When authorization is weak, attackers can use this method to crack passwords and gain access to the server.

Post-Exploitation​

Permission on NFS Servers​

After a successful breach, attackers can gain full access to files on the server. This provides access to sensitive information and can lead to further targeted attacks or data exfiltration.

Information Exfiltration​

Files on NFS servers often contain sensitive information. After a successful attack, retrieving these files and using the information therein allows attackers to further their goals or leak information.