An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device runs a custom daemon on UDP port 5978 which is called "dldps2121" and listens for broadcast packets sent on 255.255.255.255. This daemon handles custom D-Link UDP based protocol that allows D-Link mobile applications and desktop applications to discover D-Link devices on the local network. The binary processes the received UDP packets sent from any device in "main" function. One path in the function traverses towards a block of code that handles commands to be executed on the device. The custom protocol created by D-Link follows the following pattern: Packetlen, Type of packet; M=MAC address of device or broadcast; D=Device Type;C=base64 encoded command string;test=1111. If a packet is received with the packet type being "S" or 0x53 then the string passed in the "C" parameter is base64 decoded and then executed by passing into a System API. We can see at address 0x00009B44 that the string received in packet ty…