Security Bug with ZTE ZXDSL 531B Modem/Router

ZTE ZXDSL 531B is a Type II modem that was supplied by BSNL to it's BSNL Broadband (previously DataOne) subscribers free of cost upon commitment of a fixed duration or upon payment of additional charges.

While, the modem is really good at what it does, I found a security hole in it that, if exploited properly, can bring nightmare to it's users. [More]