Grandstream and DrayTek Devices Exploited to Power New Hoaxcalls DDoS Botnet 42,693 people reacted Grandstream and DrayTek Devices Exploited to Power New Hoaxcalls DDoS Botnet By Ken Hsu, Haozhe Zhang, Zhibin Zhang and Ruchna Nigam April 3, 2020 at 1:07 PM 22 7 min. read