Some wireless router models produced by Chinese company Tenda Technology are vulnerable to remote attacks, says Craig Heffner. The bug is in the httpd component, where the MfgThread() function deploys a backdoor that can execute commands from remote C&C centers. The backdoor only listens on the LAN, thus it is not exploitable from the WAN. However, it is exploitable over the wireless network, which has WPS enabled by default with no brute force rate limiting.”]
Source: https://www.bitdefender.com/blog/hotforsecurity/tenda-wireless-routers-feature-backdoor/