The Netcore and Netis routers have an open, which can be accessed from the Internet side of the router. The password needed to open up this backdoor is hardcoded into the router’s firmware. Using the backdoor, hackers could upload or download hostile code and even modify the settings on vulnerable routers in order to to monitor a person’s Internet traffic as part of a so-called man-in-the-middle (MitM) attack. Almost all of the routers are in China, with much smaller numbers in other countries, including South Korea, Israel, Israel and the United States.
Source: https://thehackernews.com/2014/08/hardcoded-backdoor-found-in-china-made_27.html