Blind Arithmetic Evaluation Differential : SQL Injection - php

Question

I am getting SQL & URL injection vulnerabilities when I scan my website. This is the code I'm using:
if(isset($_GET["id"]))
{
if(!is_int($_GET["id"]) ==FALSE)
{
//redirect this person back to homepage
} else {
$sql = "SELECT * FROM workshop WHERE id=".trim($_GET['id']);
$result = mysql_query($sql);
$row = mysql_fetch_assoc($result);
$id = $row['id'];
$prod_name = $row['prod_name'];
$description = $row['description'];
$image1 = $row['image1'];
$image2 = $row['image2'];
$image3 = $row['image3'];
$pdfFileName = $row['pdfFileName'];
$publish = $row['publish'];
$workshop_date = $row['workshop_date'];
$workshop_date_end = $row['workshop_date_end'];
$course_desc = $row['course_desc'];
$attend = $row['attend'];
$trainer_detail = $row['trainer_detail'];
$location = $row['location'];
$dateValue = $row['workshop_date'];
$year = date('Y',strtotime($dateValue));
$month = date('F',strtotime($dateValue));
$day = date('d',strtotime($dateValue));
$dateValue1 = $row['workshop_date_end'];
$year1 = date('Y',strtotime($dateValue1));
$month1 = date('F',strtotime($dateValue1));
$day1 = date('d',strtotime($dateValue1));
}
}
How do I fix it?

Answer 1

The SQL injection problem is in this row:
$sql = "SELECT * FROM workshop WHERE id=".trim($_GET['id']);
You're applying the value from get directly into your query without escaping it.
Do this instead:
$id = mysql_real_escape_string(trim($_GET['id']));
$sql = "SELECT * FROM workshop WHERE id=$id";
Remember that you're using deprecated mysql_* functions, mysqli_* should be used instead. Consider updating your code.