用户提问: 555-1; waitfor delay '0:0:15' --
Ai回答: This payload is a time-based SQL injection test. Let's break it down for educational purposes (⚠️ only for legal security research):
Payload Analysis:
```sql
555-1; waitfor delay '0:0:15' --
```
# 1. Structure:
- `555-1` → Invalid input (forces an error or non-existent record).
- `;` → Query separator (executes multiple statements if SQL injection is possible).
- `waitfor delay '0:0:15'` → Introduces a 15-second delay (SQL Server syntax).
- `-- ` → Comment (neutralizes the rest of the original query).
# 2. Purpose:
- Tests for blind SQL injection where the attacker cannot see direct output.
- If the database executes the `WAITFOR DELAY` command, the application will pause for 15 seconds before responding.
- This confirms time-based SQL injection vulnerability (the attacker can control database execution timing).
# 3. Expected Behavior:
- Secure App:
- Rejects or sanitizes the input, executes no delay.
- May return an error (if input validation is strict).
- Vulnerable App:
- Pauses for 15 seconds before responding (proving SQL injection exists).
- Attackers can then use this to extract data bit by bit (e.g., `IF (condition) WAITFOR DELAY '0:0:5'`).
Why Attackers Use This:
- Blind Data Extraction:
- If the attacker can't see database output, they can infer data by measuring response times.
- Example:
```sql
IF (SELECT SUBSTRING(@@version,1,1) = 'M') WAITFOR DELAY '0:0:5' --
```
- If the response is delayed, the first character of `@@version` is `'M'` (Microsoft SQL Server).
- Bypasses Basic Defenses:
- Works even if error messages are hidden (unlike error-based SQLi).
- Harder to detect than boolean-based SQLi (no visible output changes).
How to Prevent This:
1. Use Parameterized Queries (Prepared Statements):
```python
# Python (SQL Server example)
cursor.execute("SELECT * FROM users WHERE id = ?", (user_id,))
```
2. Disable Stacked Queries (if possible):
- Many ORMs (like Django, SQLAlchemy) prevent multiple statements by default.
- In raw SQL, avoid allowing `;` in user input.
3. Input Validation & Sanitization:
- Reject unexpected characters (`;`, `--`, `WAITFOR`, etc.).
- Whitelist allowed formats (e.g., only numbers for IDs).
4. Web Application Firewall (WAF):
- Blocks suspicious patterns (`WAITFOR DELAY`, `SLEEP()`, `BENCHMARK()`).
5. Least Privilege Database Access:
- Restrict application DB users from executing dangerous commands like `WAITFOR`.
Legal Testing Alternative:
Try this in a controlled environment (e.g., [DVWA](https://dvwa.co.uk/) or [OWASP Juice Shop](https://owasp.org/www-project-juice-shop/)):
```sql
-- Time-based test (SQL Server)
1; IF (1=1) WAITFOR DELAY '0:0:5' --
```
- If the page takes 5 seconds to load, SQL injection is possible.
Further Learning:
- Time-Based SQLi Techniques:
- [PortSwigger: Blind SQLi with Time Delays](https://portswigger.net/web-security/sql-injection/blind/time-delays)
- Secure Coding:
- [OWASP SQL Injection Prevention](https://cheatsheetseries.owasp.org/cheatsheets/SQL_Injection_Prevention_Cheat_Sheet.html)
Would you like a deeper breakdown of exploiting time-based SQLi (e.g., extracting database version, table names)?
0
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提问时间: 2025-07-10 01:23:22
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