PHP Network Development Detailed: SQL injection vulnerability

SQL injection is a common tactic of network attacks, where an attacker can get a management account, password, and more information by pooling the SQL statements in the page. This attack Method The harm to the website is very big.

general approach to SQL injection attacks

The following code is a simple data output page that is passed from the Browser The address bar gets the parameters to display the appropriate content.
<?php
$id = $_get[' id ']; Get parameters
$sql = "SELECT * from posts WHERE PostID = $id"; Defining SQL
mysql_connect ("localhost", "root"); Connecting to a server
mysql_select_db ("guestbook"); Connecting to a database
$rs = mysql_query ($sql); Execute SQL
if (Mysql_numrows ($RS))//If the record exists, the output
{
$row _rs = Mysql_fetch_assoc ($RS);
echo "TOPIC:". $row _rs[' TOPIC ']. " <br> ";
}
else </