Rating:

* Upload a sufficient number of files for the tar archive to exceed 10 records * 20 blocks * 512 bytes = 102400 bytes (the default "checkpoint")
* Exploit the wildcard character in the `tar` command by naming a file `--checkpoint-action=exec=sh shell.txt `

[Read the writeup here](https://ctf.zeyu2001.com/2021/cybersecurityrumble-ctf/enterprice-file-sharing)

Original writeup (https://ctf.zeyu2001.com/2021/cybersecurityrumble-ctf/enterprice-file-sharing).