Is it safe to sanitize input data in PHP?

Is it safe to sanitize input data in PHP?

We think it’s fair to assume that it’s written in PHP as the form’s action is index.php. In this code, the query string parameter search is echoed back to the user without sanitization. An attacker could email or IM unsuspecting users a crafted URL that escapes out of the and does nasty things with JavaScript.

Which is the safest way to sanitize HTML?

Examples include a search results page, a blog commenting system, dictionary.com’s word of the day, etc. In this context, all HTML meta characters need to be encoded or stripped. That’s primarily < and >, but using PHP’s FILTER_SANITIZE_SPECIAL_CHARS is probably safer, and FILTER_SANITIZE_STRIPPED is probably the safest.

How to sanitize input data without doing anything malicious?

In this code, the query string parameter search is echoed back to the user without sanitization. An attacker could email or IM unsuspecting users a crafted URL that escapes out of the and does nasty things with JavaScript. A simple way to test for this exploit without doing anything malicious is to use a URL like this:

Which is the correct attribute for allowhtml in MVC?

In any case, adding [AllowHtml] attribute is the right answer, as it allows html to be deserialized in the controller. Example in your viewmodel: I faced the same issue although i added [System.Web.Mvc.AllowHtml] to the concerning property as described in some answers.

When to sanitize data in the output context?

Data should be further sanitized on output depending on context. Sanitization involves transforming (possibly destructively) the data to be safe in the output context. Remember that sometimes a single piece of data may be used in multiple contexts on the same page.

Is there a way to sanitize special chars?

FILTER_SANITIZE_SPECIAL_CHARS works here as well. In addition, all attribute values should be quoted using single or double quotes or you’ll be hit like the examples above. For event handling attributes like onmouseover, onclick, onfocus, onblur or similar, you need to be more careful.