FreeWebshop <= 2.2.9 R2 (ajax_save_name.php) Remote Code Execution Vulnerability

[n0b0d13s () gmail com]

FreeWebshop <= 2.2.9 R2 (ajax_save_name.php) Remote Code Execution Vulnerability

author...............: Egidio Romano aka EgiX
mail.................: n0b0d13s[at]gmail[dot]com
software link........: http://www.freewebshop.org/
affected versions....: from 0.9.12 to 2.2.3

[-] vulnerable code in /addons/tinymce/jscripts/tiny_mce/plugins/ajaxfilemanager/ajax_save_name.php

37. @ob_start();
38. include_once(CLASS_SESSION_ACTION);
39. $sessionAction = new SessionAction(); 
40. $selectedDocuments = $sessionAction->get();
41. if(removeTrailingSlash($sessionAction->getFolder()) == getParentPath($_POST['id']) && sizeof($selectedDocuments))
42. {
43. if(($key = array_search(basename($_POST['id']), $selectedDocuments)) !== false)
44. {
45. $selectedDocuments[$key] = $_POST['value'];
46. $sessionAction->set($selectedDocuments);
47. 
48. }
49. echo basename($_POST['id']) . "\n";
50. displayArray($selectedDocuments);
51. 
52. }elseif(removeTrailingSlash($sessionAction->getFolder()) == removeTrailingSlash($_POST['id']))
53. {
54. $sessionAction->setFolder($_POST['id']);
55. }
56. writeInfo(ob_get_clean());

An attacker could be able to manipulate the $selectedDocuments array that will be displayed at line 50,
then at line 56 is called the 'writeInfo' function using the current buffer contents as argument.
Like my recently discovered vulnerability (http://www.exploit-db.com/exploits/18075/), this function
writes into a file called 'data.php' so an attacker could be able to execute arbitrary PHP code.

[-] Disclosure timeline:

[24/11/2011] - Vulnerability discovered
[25/10/2011] - Issue reported to http://www.freewebshop.org/forum/?topic=5235
[15/11/2011] - After three weeks still no fix released
[16/11/2011] - Public disclosure

[-] Proof of concept:

http://www.exploit-db.com/exploits/18121