Since it is an integer you also obviously do not need to add quotes to the sql column name. You are already telling it to essentially make sure that the value will be an integer. If you're casting the variable to an int, you don't need to escape anything. This covers strings, as the function name implies, but what about numbers? You could do (int)$mysqli->real_escape_string($_POST), which would certainly work, but that's redundant. If you'll be using a LIKE clause, then you should also do addcslashes($escaped, '%_'), since mysqli::real_escape_string won't do this as stated here. Without quotes, strings are still equally susceptible to SQL injection. Notice how similar to the first example, I still added quotes to the column value. An easy fix to this would be to do: $name = $mysqli->real_escape_string($_POST) SELECT * FROM myTable WHERE name='' OR '1'='1'Ī hacker could do a lot of damage to your site if your queries are set up like this. Take a look at what is actually happening to the statement. Just imagine what could happen if it were a DELETE query instead. In this case, the malicious user now has access to your entire table. Now this statement will always evaluate to true, since 1=1. The problem with this, is that if it is based off of user input, like in the example, then a malicious user could do ' OR '1'='1. $mysqli->query("SELECT * FROM myTable WHERE name='$name'") In a normal MySQL call, you would do something like: $name = $_POST Before I start, if you're wondering exactly how the " Bobby Tables Attack" works, check out this explanation. Now that we're done with the theory, let's get to practice. All credit for the image goes to this site for this classic piece of rhetoric. The following iconic comic, known as Bobby Tables, is an excellent portrayal of how an SQL injection attack might work. When it comes to security, you should never be complacent, no matter how secure you think your system is.
The goal of this tutorial is to transform someone with little to no knowledge of prepared statements, into an expert.ĭisclaimer: Don't actually be as laid back as this database manager. Prepared statements may seem intimidating at first, but once you get hang of it, it’ll seem like second nature to you. Escaping is not necessary, since it will treat the values as literals all attempts to inject sql queries will be interpreted as such. You basically just create the query template with placeholder values, and then replace the dummy inputs with the real ones. If implemented correctly, prepared statements (aka parameterized queries) offer superior protection against SQL injection. However, it is undoubtedly a good idea to take proper precautions. Hopefully this scenario will never happen to your website.
Why? You know that these scrubs are are no match for those prepared statements you coded! In fact, you find this humorous, as these hackers will likely be annoyed that they wasted their time with futile attempts. Ironically, as the database manager, you remain the calmest. An impromptu staff meeting has been called at 2am, and everyone in the company is freaking out. Also, here's a great resource to learn PDO prepared statements, which is the better choice for beginners and most people in general.Ī hack attempt has recently been discovered, and it appears they are trying to take down the entire database. Before I start, if you'd like to see an even easier way to use MySQLi prepared statements, check out my wrapper class.
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