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网页木马US-ASCII码,unicode码的加密解密
樱木花盗 发表于 2007-3-31 4:34:15 |
转自：7jdg's Blog
http://1v1.name/?action=show&id=61
US-ASCII加密,就是把7bit转换为8bit
原始的代码
<html>
<title>7jdg's Blog</title>
<script>alert('Hello World')</script>
<body>
<a href="http://1v1.name">http://1v1.name</a>
</body>
</html> |
加密后的代码
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII" />
<title>Bypassing of web filters by using ASCII Exploit By CoolDiyer</title>
</head><body>
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</body></html> |
加密解密程序
＃i nclude <stdio.h>
int main(int argc,char** argv)
{
FILE *fp;
char ch;
printf("\n-- Bypassing of web filters by using ASCII Exploit By CoolDiyer --\n");
if(argc<2){
printf("\nUsage: \n\t %s srcfile >destfile\n",argv[0]);
return -1;
}
if((fp=fopen(argv[1],"r"))==NULL){
printf("File %s open Error",argv[1]);
return -1;
}//指定编码为US-ASCII是必须的
printf("\n<html>\n<head>\n<meta http-equiv=\"Content-Type\" content=\"text/html; charset=US-ASCII\" />\n<title>Bypassing of web filters by using ASCII Exploit By CoolDiyer</title>\n</head><body>\n");
while((ch=fgetc(fp))!=EOF){
ch|=0x80; //把7位变成8位，这句话是核心，解密时用 ch&=0x7f
printf("%c",ch);
};
fclose(fp);
printf("\n</body></html>\n");
return -1;
} | 解密只要把每个字节的高位置0即可。还有一个更简单的方法，网页“另存为”保存的时候，在语言选项将“西欧(windows)”改成“简体GB2312”，然后保存在本地。
unicode编码前
<html>
<title>7jdg's Blog</title>
<script>alert('Hello World')</script>
<body>
<a href="http://1v1.name">http://1v1.name</a>
</body>
</html> |
unicode编码以后的形式
<html>
<title>7jdg's Blog</title>
<script>alert('Hello World')</script>
<body>
<a href="http://1v1.name">http://1v1.name</a>
</body>
</html> |
加密程序
<?
$text = "http://1v1.name";
preg_match_all("/[\x80-\xff]?./",$text,$ar);
foreach($ar[0] as $v)
echo "&#".utf8_unicode(iconv("GB2312","UTF-8",$v)).";";
?>
<?
// utf8 -> unicode
function utf8_unicode($c) {
switch(strlen($c)) {
case 1:
return ord($c);
case 2:
$n = (ord($c[0]) & 0x3f) << 6;
$n += ord($c[1]) & 0x3f;
return $n;
case 3:
$n = (ord($c[0]) & 0x1f) << 12;
$n += (ord($c[1]) & 0x3f) << 6;
$n += ord($c[2]) & 0x3f;
return $n;
case 4:
$n = (ord($c[0]) & 0x0f) << 18;
$n += (ord($c[1]) & 0x3f) << 12;
$n += (ord($c[2]) & 0x3f) << 6;
$n += ord($c[3]) & 0x3f;
return $n;
}
}
?> |
这样的unicode编码，也可以通过另存为解密
或者是
<?php
$str = "http://1v1.name";
$str = preg_replace("|&#([0-9]{1,5});|", "\".u2utf82gb(\\1).\"", $str);
$str = "\$str=\"$str\";";
eval($str);
echo $str;
function u2utf82gb($c){
$str="";
if ($c < 0x80) {
$str.=$c;
} else if ($c < 0x800) {
$str.=chr(0xC0 | $c>>6);
$str.=chr(0x80 | $c & 0x3F);
} else if ($c < 0x10000) {
$str.=chr(0xE0 | $c>>12);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
} else if ($c < 0x200000) {
$str.=chr(0xF0 | $c>>18);
$str.=chr(0x80 | $c>>12 & 0x3F);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
}
return iconv('UTF-8', 'GB2312', $str);
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