Zyxel Firewall SUID Binary Privilege Escalation

This module exploits CVE-2022-30526, a local privilege escalation vulnerability that
allows a low privileged user (e.g. nobody) escalate to root. The issue stems from
a suid binary that allows all users to copy files as root. This module overwrites
the firewall's crontab to execute an attacker provided script, resulting in code
execution as root.

In order to use this module, the attacker must first establish shell access. For
example, by exploiting CVE-2022-30525.

Known affected Zyxel models are: USG FLEX (50, 50W, 100W, 200, 500, 700),
ATP (100, 200, 500, 700, 800), VPN (50, 100, 300, 1000), USG20-VPN and USG20W-VPN.