Prevention of SQL injection attacks in the application headers
The above code is a simple PHP script that uses the Laravel framework to fetch client data from a database.
The script retrieves the
idClient
value from the HTTP header and uses it directly in an SQL query. This is a classic example of an SQL Injection vulnerability.
The issue here is that the
idClient
value is not sanitized or validated before it is used in the SQL query. This means that a malicious user can modify the
idClient
header value to include SQL commands, which will then be executed by the server.
For example, an attacker could set the
idClient
header to
1; DROP TABLE clients;
, which would delete the entire clients table from the database.
This is a serious vulnerability that can lead to data loss, data corruption, unauthorized access to data, and other security issues. It is strongly recommended to sanitize and validate all input data before using it in SQL queries.
prepare("SELECT * FROM clients WHERE id = ?");
$stmt->bind_param("i", $idClient);
$stmt->execute();
$result = $stmt->get_result();
?>
The original code was vulnerable to SQL Injection because it directly used the value from the
idClient
header in the SQL query. This means that if an attacker was able to modify the
idClient
header, they could potentially manipulate the SQL query to their advantage.
The fixed code uses a prepared statement to prevent this type of attack. Here's how it works:
1. Instead of directly inserting the
idClient
into the SQL query, a placeholder (
?
) is used. This placeholder will later be replaced by the actual
idClient
value.
2. The
prepare
function is called on the
$conn
object (which represents the database connection) with the SQL query as its argument. This function returns a new statement object.
3. The
bind_param
function is called on the statement object. This function binds the
idClient
value to the placeholder in the SQL query. The
"i"
argument means that the
idClient
value should be treated as an integer.
4. The
execute
function is then called on the statement object to run the SQL query.
5. Finally, the
get_result
function is called on the statement object to retrieve the result of the SQL query.
This way, even if an attacker tries to inject SQL commands into the
idClient
header, these commands will not be executed because they are treated as a string, not as part of the SQL query.