Defender Sentinel 21031

So a while back, I purchased one of these things: Defender Sentinel 21031. It is a pretty good unit. Cameras are nice. It’s basically for home monitoring.

Being a bit security conscious (read: paranoid), I took a look at the open ports on this device. I saw that telnet was open, but I couldn’t get in using any of the passwords set. After writing to the company, it turns out they don’t reveal the root password to the device. That was an unacceptable answer for me, so I took to checking out what’s under the hood.

The above image shows what’s inside the box. Not much. You can also see in this picture, that I have a RS232 converter hooked up to the box. I needed 5V for the board, which I got with the Red (5V) and Green (GND) wires. Then I also have the Purple (RX) and Yellow (TX) wires hooked up. Firing up the serial port program at 115200 baud with the usual 8N1 settings I was able to halt the boot sequence.

Once that was done, I was able to boot into single user mode, and extract the /etc/passwd file which contained:

I’m currently running John the Ripper on the hash to see what the password is. I’ll update this post when I get it.

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4 thoughts on “Defender Sentinel 21031

    1. Nah, I’ve actually thrown out the unit. Pain to use. I’m replacing it with a laptop, two 4 channel USB tuner cards and the Motion software that’s free and open source.

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