PHP Snippet #06

This challenge covers the review of a snippet of code written in PHP

PRO
Tier
Easy
< 1 Hr.
1085

Course


The Code Review Snippet challenges are designed to help you identify vulnerabilities in a small piece of code. This particular challenge involves a mix of HTML and PHP, where an 'a' tag is created with an 'href' attribute containing a PHP echo statement. The issue lies in the improper encoding of single quotes by the `htmlentities()` function, which can be exploited by an attacker to inject malicious attributes like `onClick` or `onMouseOver` into the 'a' tag.

In the video, we discuss how `htmlentities()` encodes several characters to HTML entities but does not encode single quotes by default. This oversight allows an attacker to manipulate the 'href' attribute by inserting a single quote in their username. To mitigate this vulnerability, developers should either use double quotes in the 'href' attribute or add the `ENT_QUOTES` flag to `htmlentities()` to ensure single quotes are also encoded.

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