RSYNC

Rsync is a fast and efficient tool for locally and remotely copying files. Rsync reduces the amount of data transmitted over the network when a version of the file already exists on the destination host. It does this by sending only the differences between the source files and the older version of the files that reside on the destination server. It is often used for backups and mirroring. You could use HackTricks page to view more ways to abuse Rsync: [LINK]

Tips2Hack

1. Nmap - Rsync Scan

sudo nmap -sV -p 873 13.13.13.13

1. Probing for Accessible Share

nc -nv 13.13.13.13 873

1. Enumerating an Open Share

rsync -av --list-only rsync://13.13.13.13/
rsync -av --list-only rsync://13.13.13.13/share

1. Downloading a file from Open Share

rsync -av --list-only rsync://13.13.13.13/share/file /local/directory