CVE-2021-29505 PoC — XStream is vulnerable to a Remote Command Execution attack

Source

https://github.com/MyBlackManba/CVE-2021-29505

Associated Vulnerability

Title: XStream is vulnerable to a Remote Command Execution attack (CVE-2021-29505)
Description:XStream is software for serializing Java objects to XML and back again. A vulnerability in XStream versions prior to 1.4.17 may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types is affected. The vulnerability is patched in version 1.4.17.

Description

对CVE-2021-29505进行复现，并分析学了下Xstream反序列化过程

Readme

## 复现过程
在IDEA中导入xstream组件的jar包，本次复现所使用的是CommonsCollections6链来进行利用，故导入commons-collections组件jar包,POC详见附件。
首先使用ysoserial启动一个恶意RMI服务端进行监听，并利用了CommonsCollections6链进行命令执行，如下所示：
```txt
java -cp .\ysoserial.jar ysoserial.exploit.JRMPListener 1099 CommonsCollections6  "calc"
```
![1.png](1.png)
同时根据该漏洞对Xstrean的反序列化流程进行了分析调试做了记录，详见`xstream反序列化流程分析.pdf`

File Snapshot

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