2049 - NFS

Finding NFS services:

nmap -sV -T4 -p111,2049 <IP>

Starting Nmap 7.92 ( https://nmap.org ) at 2022-07-19 14:58 BST
Stats: 0:00:07 elapsed; 0 hosts completed (1 up), 1 undergoing Service Scan
Service scan Timing: About 0.00% done
Nmap scan report for HOSTNAME (IP)
Host is up (0.00070s latency).

PORT     STATE SERVICE VERSION
111/tcp  open  rpcbind 2-4 (RPC #100000)
2049/tcp open  nfs_acl 3 (RPC #100227)

We can verify is the NFS service is actually running by querying a specific port and program number.

rpcinfo -p <IP>
   program vers proto   port  service
    100000    4   tcp    111  portmapper
    100000    3   tcp    111  portmapper
    100005    2   udp  50393  mountd
    100005    2   tcp  40745  mountd
    100005    3   udp  44139  mountd
    100005    3   tcp  52651  mountd
    100003    3   tcp   2049  nfs
    100003    4   tcp   2049  nfs
    100227    3   tcp   2049
    100003    3   udp   2049  nfs
    100227    3   udp   2049
    100021    1   udp  50710  nlockmgr
    100021    3   udp  50710  nlockmgr
  
rpcinfo -n 2049 -t <IP> 100003
    program 100003 version 3 ready and waiting
    program 100003 version 4 ready and waiting                                              

View the mounts that have been exported

showmount -e <IP>
    Export list for <IP>:
    /export/data
    /export

Now create a local directory that you will want to mount the exported share to

mkdir /tmp/directory

Mount the share

sudo mount -t nfs <IP>:/export /tmp/export
    Created symlink /run/systemd/system/remote-fs.target.wants/rpc-statd.service → /lib/systemd/system/rpc-statd.service.

We can now see the files and folders mounted to the local directory we created

ls -la /tmp/export
    total 12
    drwxr-xr-x  3 root root  4096 Jan 26  2021 .
    drwxrwxrwt 13 root root  4096 Jul 19 14:47 ..
    drwxrwxr-x  5 root 10000 4096 Jan 25 09:53 data

From here, if you get "permission denied" when browsing the file and folder. Simple create a user with the same UID. That user should then get full access to the directory

Unmounting NFS File Systems

The umount command detaches (unmounts) the mounted file system from the directory tree.

To detach a mounted NFS share, use the umount command followed by either the directory where it has been mounted or remote share:

umount <IP>:/backups umount /var/backups

Last updated