Captcha problem users just refresh and it will let them auto submit again

Posted on 16th Feb 2014 by admin

Users will just re submit and not have to enter the new captcha.. ? Lol but if i refresh the page, the captcha auto makes a new1 so u cant submit.

But if u enter captcha code alrdy, then submit form correctly, and press refresh to auto submit form, it does it? This is a major security risk here is my code, thanks:

Code: session_start();

$RandomStr = md5(microtime());// md5 to generate the random string
$text = rand(10000,99999);
$_SESSION["key"] = $text;
$height = 25;
$width = 35;

$image_p = imagecreate($width, $height);
$black = imagecolorallocate($image_p, 100, 5, 5);
$white = imagecolorallocate($image_p, 155, 155, 025);
$font_size = 16;
$text=substr($_SESSION['key'],0,3);
imagestring($image_p, $font_size, 5, 5, $text, $white);
imagejpeg($image_p, null, 80);

then my HTML:

Code: <tr class="bts ce"><td colspan=2><b>Security Code Confirmation</b></td></tr>

<tr>
<td align="right">Your unique security code<input type="hidden" name="secId" value="76c2b0e6f20ed0f1b209bcf39dee8e06"></td>
<td>
<img src="php_captcha.php">

<span class="desc">If The images are broke, please contact us.</span></span>
</td>
</tr>
Is there a way so people cant auto submit form?

Captcha works if u refresh but people can just auto submit the form and it will keep submiiting...

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