Hacking ZyXEL Gateways – This paper is the result of various security assessments performed on several ZyXEL Prestige devices in both, a controlled environment (computer lab) and production environments during several penetration tests.
You can download it from the following link: https://packetstormsecurity.com/files/download/63827/Hacking_ZyXEL_Gateways.pdf
Source: https://packetstormsecurity.com/files/63827/Hacking_ZyXEL_Gateways.pdf.html