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帮助MySQL查询

[英]Help with a MySQL query

我被问到一个问题,但是我什至无法开始回答,所以有人可以给我一个想法,就是开始如何回答这个问题,

我不是在寻找答案,而只是在教一些如何回答它

开始:

假设“ regsister_globals”和“ magic_quotes_gpc”已打开,那么这段代码有什么问题? 记录可能的漏洞,然后修复以产生安全版本(存在4个错误)

$p = $_GET["p"];
if ($sp == "index.php") {

     if ($_get["id"] == 345)
          $filter - addslashes($_get["id"]);

     $sql = "SELECT * FROM users WHERE id = {$filter}";
     $row - mydql_fetch_assoc(mysql_query($sql));

     echo <<< HTML
     <html>
           ...... user details .....
     </html>
HTML. 
} else 
      include ($p);

搜寻“ SQL注入”和“输入验证”应该可以帮助您入门。

考虑到环境,

“假设“ regsister_globals ”和“ magic_quotes_gpc ”已打开”

我相信这种情况是要教会您这两种设置的风险。

与上面提到的php指令结合使用时,被剪切的代码实际上有4个错误与“永远不要信任来自脚本外部的任何信息”有关。

(不仅有4个错误,还有很多其他错误;有两个“ - ”应为“ = ”,而小写的“ _get ”应为大写等),但我猜这是只是错别字。)

这应该使您开始:

漏洞1:register_globals应该关闭-这是安全隐患。

$p = $_GET["p"];
// Where does $sp come from?
if ($sp == "index.php") {

     // What the hell? So much wrong with these two lines
     // 1. if id == 345 you don't need to addslashes
     // 2. "-" should be "="
     // 3. addslashes should be mysql_real_escape_string
     // 4. the if() should be removed so it runs every time
     if ($_get["id"] == 345)
          $filter - addslashes($_get["id"]);

     // SQL injection
     $sql = "SELECT * FROM users WHERE id = {$filter}";
     // Again with the "-" instead of "="
     // Typo in the function name
     // No error checking
     $row - mydql_fetch_assoc(mysql_query($sql));

     // No escaping of database input - vulnerable to XSS attacks
     echo <<< HTML
     <html>
           ...... user details .....
     </html>
HTML. // Should be ; not .
} else 
{
      // I can include /etc/passwd by manipulating the URL
      include ($p);
}

该代码容易受到SQL注入的攻击,因为用户数据无法转义。 使用mysql_real_escape_string

mydql_fetch_assoc应该是mysql_fetch_assoc

尝试这个:

<?php
$p = $_GET["p"];
if ($p == "index.php" && $_get["id"] == 345) {

 $filter = mysql_real_escape_string($_get["id"]);

 $sql = "SELECT * FROM users WHERE id = {$filter}";
 $row = mysql_fetch_assoc(mysql_query($sql));

?>
<html>
 ...... user details .....
</html>
<?php
}
else if (strpos($p, '../')===false && file_exists($p)) {
 include $p;
}

?>
<?php
    $allow_includes = array(
      'some1', 'some2'
    );
    $p = $_GET["p"];
    if ($p == "index.php") {
         if ($_GET["id"] == 345) {
              $filter = mysql_real_escape_string($_GET["id"]);
         }

         $sql = "SELECT * FROM users WHERE id = '{$filter}'";
         $row = mysql_fetch_assoc(mysql_query($sql));
 ?>
    HTML. 
 <?php
    }
    elseif ( in_array($p, $allow_includes) ) {
      include ($p);
    }
    else {
      echo "Error 404";
    }
 ?>

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