-1
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Is this code safe from injection, xss and whole other attacks or no ?

The below code is for search box :

if(isset($_POST["query"]))
{
$output = '';
$string = $_POST['query'];
$search = htmlspecialchars($string, ENT_QUOTES, 'UTF-8');
$stmt = $con->prepare(" SELECT * FROM topics_categories WHERE cat_name LIKE 
? LIMIT 3");
$stmt->bind_param("s",$search);
$stmt->execute();
$result = $stmt->get_result();
while($row = mysqli_fetch_array($result))
{
$output .= '
<a href="topics.php?cat_id='.$row['cat_id'] .'">'.$row['cat_name'].'</a>';
}
echo $output;
}
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closed as unclear what you're asking by πάντα ῥεῖ, Mike Brant, alecxe, Denis, t3chb0t Jun 7 '17 at 4:38

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    \$\begingroup\$ I am guessing this code doesn't really work the way you expect it to. Your LIKE clause is not really doing a LIKE search. And I have no idea as to why you would be using htmlspecialchars() the way you are. \$\endgroup\$ – Mike Brant Jun 6 '17 at 22:44
  • \$\begingroup\$ it's work i just want to know it's safe or no , how should i using htmlspecialchars() ? \$\endgroup\$ – Beginner Jun 6 '17 at 22:46
0
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Searches are customarily done using HTTP GET requests rather than POST requests, since they do not modify information on the server.


You are not applying escaping correctly.

  • Why are you performing HTML escaping here?

    $search = htmlspecialchars($string, ENT_QUOTES, 'UTF-8');
    

    The data in the cat_name column should not be HTML-escaped, so it would be inappropriate to HTML-escape the search term.

  • You are neglecting to perform HTML escaping on $row['cat_name']. When you are embedding text in HTML, you need to escape it using htmlspecialchars(). Otherwise, if the cat_name happens to contain a string that looks like an HTML tag, the page could break.


Furthermore, I wouldn't bother constructing $output. It would be simpler to echo each line of output as it comes. That gets rid of two lines of clutter: $output = '' and echo $output. (There might be a slight difference in performance, but I wouldn't worry about it.)

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  • \$\begingroup\$ The lines before the link are safe ? because i didn't escape url yet . at the first i want to make sure the $_POST['query'] and sql query are safe then if they safe i want know how to make the url safe too \$\endgroup\$ – Beginner Jun 7 '17 at 0:15
  • \$\begingroup\$ Strings that should be escaped need to be escaped for a reason. Conversely, strings that don't need to be escaped should not be escaped. Don't randomly sprinkle escaping functions here and there "just in case" — you must understand why you are applying the escape. In the case of your SQL query, $stmt->bind_param(…) will apply the SQL string escaping for you. Any escaping that you manually apply to $string will just corrupt the query string. \$\endgroup\$ – 200_success Jun 7 '17 at 0:20

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