PHP - somo la 47: Jifunze kuhusu sql injection na kuizuia

Katika somo hili nitakwenda kukufundisha kuhusu php sql injection. Somo hili tutaangalia kwa ufupi kuhusu sql injection na jinsi ya kuweza kuizuia. Somo hili ni muenelezo wa masomo yetu kadhaa yaliyozungumzia usalama. Masomo mengine ni kama matumiazi ya htaccess, matumizi ya hashing, na encription pamoja na decription. Somo hili nitakuonyesha hatari ya sql injection.

 

Sql injection ni nini?

Hizi ni code shambulizi la kimtandao ambalo hufanyika kwa kuingiza sql statement kwenye ukurasa ambao mtumiaji huweka taarifa fulani. Kwa mfano ukurasa wa ku log in mtumiaji anatakiwa kuweka jina na password yake. Sasa hacker yeye ataweza code flani na kulog in bila ya kujisajili. Kwa mfano badala ya kuingiza jina na password mtumiaji anaweza kuingina '--'OR 1-1 hapo akafanikiwa ku log ina moja kwa moja.

 

Baadhi ya sql code zinazofanya injection

1. OR 1=1

2. –’ AND ..

3. ‘) OR 1=1-]

4. “OR “”=”

5. “OR=”

6. 1=1

7. UNION SELECT

8. DROP TABLE

 

Endapo mshambuliaji wa kimtandano (hacker) atafanikiwa kufanya injection anaweza kufanya mambo mengi hatari kama:-

1. Kufuta table ama database yote

2. Kufuta data

3. Kulogin

4. Kupata taarifa za watumiaji

5. Kuedit data

 

Takwimu zinaeleza kuwa sql injection ni moja kati ya njia kuu 10 ambazo hutumiwa katika ku hack. Ni miaka 20 sasa imepita toka sql injection ijulikane lakini mpaka leo bado ma hacker wanagunduwa mbinu mpya za ku hack kw akutumia njia hii. Takwimu zinaonyesha kuwa asilimia 47 ya mashambulizi ya kimtandao ya ku hack husababishwa hutokana na sql injection.

 

AINA ZA SQL INJECTION

1. In- band sql injection

Hii ni aina ya injection aambapo attack hufanyika kupitia error message ambayo hutokea kwenye web endapo kuna kitu hakipo sawa, ama kwa kutumia UNION oparator hivyo kuzuia aina hii ni vyema kila error za kwenye database yako usifanye za kawaida. Mfano iwe inaleta maneno ya kawaida kama “kuna hitilafu tafadhali jaribu tena” lakini kama error zinakuja zile za sql yenyewe  mfano hiyo hapo chini

 

1. Out-band sql injection

Hii ni injection ambayo hufanyika kupitia HTTP, DNS au SMB. Kuzuia attack hii vyema kuwa makini wakati wa kusafirisha data kwenye hizi protocal. Kwa mfano kuwa makini wakati wa kusafirisha data kwenye parameter. Vyema kama hakuna ulazima kutumia POST method.

 

WAPI INJECTION HUTOKEA

Ujumla wa maneno ni kuwa statement yote ya sql ipo hatarini ila kuna maeneo ambayo yapo hatarini sana kuwa ndio chanzo cha attack nyingi zinazotokea. Kwa kiasi kikubwa attack hutokea kwenye WHERE na kwenye SELECT hata hivyo zinaweza pia kutokea kwenye

1. UPDATE

2. INSERT

3. ORDER BY

 

NJIA ZA KUZUIA SQL INJECTIONS

Sio kitu rahisi kwa programmer kuwa mkamilifu kwa maana code zake zisiwe na makosa. Hvyo basi ni vyema kujuwa hizi njia zitakusaidia kuweka tahadhari. Njia hizo ni kama

1. Parameterized queries

2. Sanitizing 

3. validating

Katika somo hili tutakwenda kuangalia njia hizi moja baada ya njingine kw avitendo. Kwa kuwa tumeshajifunza jinsi ya ku sanitize na ku validate haitakuwa vigumu kuzifanyia kazi kwenye somo hili. Hata hivyo hapa nitafundisha hasa kuhusu hii parameterized Querry kwa kuwa tulisha jifunz akuhusu sanitizing na validating kwenye masomo yaliopita.

 

MAREJEO

Kusoma zaidi kuhusu somo hili tembelea website hizi:-

https://www.acunetix.com/websitesecurity/sql-injection/

https://www.javatpoint.com/sql-injection

https://www.invicti.com/blog/web-security/sql-injection-cheat-sheet/

https://www.guru99.com/learn-sql-injection-with-practical-example.html

Exploiting SQL Injection: a Hands-on Example | Acunetix

Prevent SQL injection vulnerabilities in PHP applications and fix them (acunetix.com)

https://geekflare.com/open-source-web-security-scanner/

 

 

 

 

MAFUNZO KWA VITENDO:

Sasa ndio tunakwnda kufanyia kazi ambacho tumekisoma hapo juu. Wacha tuone hatari ya injection. Katika somo hili tutakwenda kutengeneza simple login system ambayo ni rahisi kufanya injection. Tutaona kwa ufupi jinsi injection zinavyofanya kazi kisha tutaangalia jinsiya kuiboresha system yetu ki usalama.

 

1. Tengeneza database yenye jina sql. Kisha tengeneza table yenye jina users. Unaweza kutumia xode hizi

CREATE TABLE `users` (

  `id` int(11) NOT NULL,

  `username` varchar(50) NOT NULL,

  `email` varchar(50) NOT NULL,

  `password` varchar(255) NOT NULL,

  `status` int(1) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

 

Kumbuka kuweka id kuwa Auto Increment. Kisha ingiza data hizi

INSERT INTO `users` (`id`, `username`, `email`, `password`, `status`) VALUES

(5, 'chogozo', 'chogozo@gmail.com', 'chogozo@123', 1),

(6, 'kilimozo', 'kili@gmail.com', 'kili@321.com', 1),

(7, 'kilimozo', 'kili@gmail.com', 'e6e061838856bf47e1de730719fb2609', 1),

(8, 'mkwayu', 'admin@wikibongo.com', '0192023a7bbd73250516f069df18b500', 1);

 

Kwanza kabisa tengeneza folda liite web ndai ya folda hilo utatengeneza mafaili kadhaa kama nitakavyokutajia hapo chini.

 

1. Tengeneza faili liite registration.php kisha weka htlm form kwa ajili ya kujisajili. Tumia code hizi

<html lang="en">

<head>

   <meta charset="utf-8">

   <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

   <title>Registration form</title>

</head>

<body>

<form method="post" action="reg_script.php">

   <label for="name">User Name</label><br>

   <input type="text" id="name" placeholder="write your name" name="name"><br><br>

 

   <label for="email">Email</label><br>

   <input type="email" id="email" placeholder="write your email" name="email"><br><br>

 

   <label for="password">Password</label><br>

   <input type="password" id="password" placeholder="write your password" name="password"><br><br>

 

   <input type="submit" value="Register">

</form>

</body>

</html>

 

1. Tengeneza faili lingine liite reg_script.php hili litafanyia kazi hiyo registration form. Weka code hizi:-

<?php

include 'config.php';

 

//prepare variable

$name = ($_POST['name']);

$email = ($_POST['email']);

$password = ($_POST['password']);

$hashed_password = md5($password);

 

//insert data in database

$sql = "INSERT INTO users (username, email, password, status)

VALUES ('$name', '$email', '$hashed_password', 1)";

/** @var TYPE_NAME $conn */

if (mysqli_query($conn, $sql)) {

   header("location: login.php");

} else {

   echo "Error: " . $sql . "

<br>" . mysqli_error($conn);

}

mysqli_close($conn);

 

?>

1. Sasa tengeneza faili liite config.php hili ndilo la kuunganisha database. Weka code hizi

<?php

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "sql";

// Kufanya connection

$conn = new mysqli($servername, $username, $password, $dbname);

 

// Kuangalia connection

if (mysqli_connect_error()) {

   die("you are not connected: " . mysqli_connect_error());

}

?>

1. Tengeneza faili lingine la login.php kisha weka code hizi

<html lang="en">

<head>

   <meta charset="utf-8">

   <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

   <title>Login form</title>

</head>

<body>

<form method="post" action="login-script.php">

   <label for="name">User Name</label><br>

   <input type="text" id="name" placeholder="write your name" name="name"><br><br>

 

   <label for="password">Password</label><br>

   <input type="text" id="password" placeholder="write your password" name="password"><br><br>

 

   <input type="submit" value="Login">

</form>

</body>

</html>

1. Sasa tengeneza faili lingine liite login-script.php hili ni kwa ajili ya kuchakata code za ku log in.

<?php

session_start();

include 'config.php';

 

//prepare variable

$name = ($_POST['name']);

$password = ($_POST['password']);

$hashed_password = md5($password);

 

/** @var TYPE_NAME $conn */

$sql = mysqli_query($conn, "SELECT * FROM `users` where username ='$name'");

while($fetch = mysqli_fetch_array($sql)){

   ?>

   <?php

//session start

   $_SESSION['username'] = $name;

// go to dashboard

   header("location: dashboard.php");

 

 

   ?>

<?php }

 

1. Tengeneza faili liite session.php kisha weka code hizi

<?php

//Start the session

session_start();

 

Tengeneza faili liite logout.php kisha weka code hizi

<?php

//Start the session

session_start();

 

session_destroy();

header("location: login.php");

 

1. Tengeneza faili liite dashboard.php kisha wweka code hizi

<?php

include 'config.php';

include 'session.php';

?>

<html lang="en">

<head>

   <meta charset="utf-8">

   <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

   <title>Dashboard</title>

</head>

<body>

 

<?php

//kwa ajili ya kuangalia kama session imeanzishwa

if(!isset($_SESSION['username'])):

 

  ?>

 

<b><a class="btn btn-primary btn-lg" href="login.php">Login</a></b>

<?php else: ?>

   <?php

$p = $_SESSION['username'];

echo $p;

   ?>

<?php include 'menu.php';?>

   <style>

 

       table {

           width: auto;

           border-collapse: collapse;

           margin: 10px auto;

       }

       th,

       td {

           height: 50px;

           vertical-align: center;

           border: 1px solid black;

       }

 

 

   </style>

<table>

   <th>ID</th>

   <th>name</th>

   <th>Email</th>

   <th>View</th>

   <?php

   /** @var TYPE_NAME $conn */

   $file = mysqli_query($conn, "SELECT * FROM `users`");

   while($fetch = mysqli_fetch_array($file)){

       ?>

       <tr>

           <td><?php echo $fetch['id']; ?></td>

           <td><?php echo $fetch['username']; ?></td>

&n...