<小迪安全>-文件上传之WAF绕过及安全修复

文章探讨了文件上传时如何通过修改Content-Disposition、filename等参数进行绕过检测的方法,包括数据溢出、符号变异、数据截断等技巧。同时,提出了后端验证、MIME检测、内容检查以及使用WAF等安全修复方案来防止恶意文件上传。
  1. #上传参数名解析: 明确哪些东西能修改?

Content-Disposition:一般可更改

name:表单参数值,不能更改

filename:文件名,可以更改

Content-Type:文件MIME,视情况更改


常见绕过方法

 数据溢出-防匹配(xxx...) :就是在关键点前面写入大量的无用数据来干扰对后面主要数据的检测

符号变异-防匹配(' " ; ):有的检测可能是基于单引号和双引号来获取数据,可以修改单引号或双引号的位置或增加删除单双引号来干扰waf

数据截断-防匹配(%00; 换行)

重复数据-防匹配(参数多次)

Payload : 大量垃圾数据缓冲溢出(Ccontent-Disposition,filename等)

#单引号、双引号、分号

filename=x.php

filename="x.php

filename='x.php ;

filename="a.jpg;.php";

# %00、换行

filename="Content-Disposition : form-data;name="upload_file" ; x.php"

filename="x.jpg" ;

filename="x.jpg" ; . . . ..filename="x.php";

filename=

"x .

p

h

p"

;

  • 垃圾数据

  •  修改单/双引号

  • ;截断

  •  重复参数


  • /绕过 

 #文件上传安全修复方案

后端验证:采用服务端验证模式后缀检测:

基于黑名单,白名单过滤M工ME检测:

基于上传自带类型检测

内容检测:文件头,完整性检测

自带函数过滤:参考uploadlabs函数

自定义函数过滤:function check_file(){ }

WAF防护产品:宝塔,云盾,安全公司产品等

资源

https://github.com/fuzzdb-project/fuzzdb 

TheKingOfDuck/fuzzDicts: Web Pentesting Fuzz 字典,一个就够了。 (github.com)

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <display-name>web application framework</display-name> <resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/waf</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> <session-config> <session-timeout>60</session-timeout> <cookie-config><name>JSESSIONID</name></cookie-config> </session-config> <context-param> <param-name>contextConfigLocation</param-name> <param-value> classpath:spring_context.xml ,classpath:quartz_context.xml ,classpath:spring_context_misc.xml ,classpath:bpms_context.xml, classpath:process_group.xml </param-value> </context-param> <listener> <listener-class>cn.ccccltd.waf.listener.SessionListener</listener-class> </listener> <listener> <listener-class>cn.ccccltd.waf.listener.CacheFileEvent</listener-class> </listener> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <listener> <listener-class>org.apache.commons.fileupload.servlet.FileCleanerCleanup</listener-class> </listener> <listener> <listener-class>cn.ccccltd.bpms.BpmsInitializer</listener-class> </listener> <listener> <listener-class>cn.ccccltd.bpms.ou.listener.BpmsSessionListener</listener-class> </listener> <filter> <filter-name>SigninFilter</filter-name> <filter-class>cn.ccccltd.waf.SigninFilter</filter-class> <init-param> <param-name>signinUrlPattern</param-name> <param-value>bo,dhtml,dhtm,shtml,shtm</param-value> </init-param> </filter> <filter-mapping> <filter-name>SigninFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- ****************************************************************************** --> <filter> <filter-name>xssFilter</filter-name> <filter-class>cn.ccccltd.waf.filter.XssFilter</filter-class> </filter> <filter-mapping> <filter-name>xssFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter> <filter-name>SSOLoginFilter</filter-name> <filter-class>cn.ccccltd.waf.sso.controller.SSORequestController</filter-class> </filter> <filter-mapping> <filter-name>SSOLoginFilter</filter-name> <url-pattern>*.bo</url-pattern> </filter-mapping> <!--<filter> <filter-name>springSessionRepositoryFilter</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>springSessionRepositoryFilter</filter-name> <url-pattern>/*</url-pattern> <dispatcher>REQUEST</dispatcher> <dispatcher>ERROR</dispatcher> </filter-mapping>--> <servlet> <servlet-name>appDispatcher</servlet-name> <servlet-class>cn.ccccltd.waf.AppDispatcher</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring_dispatcher_context.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <!-- Spring MVC 请求映射 --> <servlet-mapping> <servlet-name>appDispatcher</servlet-name> <url-pattern>*.bo</url-pattern> </servlet-mapping> <servlet> <servlet-name>appLoader</servlet-name> <servlet-class>cn.ccccltd.waf.AppLoader</servlet-class> <load-on-startup>2</load-on-startup> </servlet> <servlet> <servlet-name>monitorLoader</servlet-name> <servlet-class>cn.ccccltd.waf.MonitorLoader</servlet-class> <load-on-startup>30</load-on-startup> </servlet> <servlet> <servlet-name>fileUpload</servlet-name> <servlet-class>cn.ccccltd.waf.tool.FileUpload</servlet-class> <load-on-startup>97</load-on-startup> </servlet> <servlet> <servlet-name>randomCode</servlet-name> <servlet-class>cn.ccccltd.waf.tool.RandomCode</servlet-class> <load-on-startup>99</load-on-startup> </servlet> <servlet-mapping> <servlet-name>appDispatcher</servlet-name> <url-pattern>*.dhtml</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>appDispatcher</servlet-name> <url-pattern>*.dhtm</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>appDispatcher</servlet-name> <url-pattern>*.shtml</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>appDispatcher</servlet-name> <url-pattern>*.shtm</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>fileUpload</servlet-name> <url-pattern>/waf/tool/fileUpload</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>randomCode</servlet-name> <url-pattern>/waf/tool/randomCode</url-pattern> </servlet-mapping> <servlet> <servlet-name>FileUploadServlet</servlet-name> <servlet-class>cn.ccccltd.comm.upload.FileUploadServlet</servlet-class> <init-param> <param-name>fileSizeLimit</param-name> <param-value>2000</param-value> </init-param> </servlet> <servlet> <servlet-name>DeleteFileServlet</servlet-name> <servlet-class>cn.ccccltd.comm.upload.DeleteFileServlet</servlet-class> </servlet> <servlet> <servlet-name>FileDownloadServlet</servlet-name> <servlet-class>cn.ccccltd.comm.upload.FileDownloadServlet</servlet-class> </servlet> <!-- 帆软报表 --> <!-- <servlet> <servlet-name>ReportServer</servlet-name> <servlet-class>com.fr.web.ReportServlet</servlet-class> <load-on-startup>0</load-on-startup> </servlet> <servlet-mapping> <servlet-name>ReportServer</servlet-name> <url-pattern>/ReportServer</url-pattern> </servlet-mapping> --> <servlet-mapping> <servlet-name>FileDownloadServlet</servlet-name> <url-pattern>/FileDownloadServlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>FileUploadServlet</servlet-name> <url-pattern>/FileUploadServlet</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>DeleteFileServlet</servlet-name> <url-pattern>/DeleteFileServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <!-- error-page START --> <!-- 400 --> <error-page> <error-code>400</error-code> <location>/errorPage.jsp</location> </error-page> <!-- 403 --> <error-page> <error-code>403</error-code> <location>/errorPage.jsp</location> </error-page> <!-- 404 --> <error-page> <error-code>404</error-code> <location>/errorPage.jsp</location> </error-page> <!-- 500 --> <error-page> <error-code>500</error-code> <location>/errorPage.jsp</location> </error-page> <!-- error-page END --> </web-app>那你给我修改一下文件都在项目之中。
06-11
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
红包 添加红包
表情包 插入表情
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值