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Resolve vulnerability: Improper neutralization of special elements used in an SQL Command ('SQL Injection')

Neil McCorrisonrequested to merge
remediate/improper-neutralization-of-special-elements-used-in-an-sql-comm-D20250619T054444 into main

MR created from vulnerability: Improper neutralization of special elements used in an SQL Command ('SQL Injection')

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Description:

Detected user input used to manually construct a SQL string. This is usually bad practice because manual construction could accidentally result in a SQL injection. An attacker could use a SQL injection to steal or modify contents of the database. Instead, use a parameterized query which is available by default in most database engines. Alternatively, consider using an object-relational mapper (ORM) such as SQLAlchemy which will protect your queries.

SQL Injections are a critical type of vulnerability that can lead to data or system compromise. By dynamically generating SQL query strings, user input may be able to influence the logic of an SQL statement. This could lead to an malicious parties accessing information they should not have access to, or in some circumstances, being able to execute OS functionality or code.

Replace all dynamically generated SQL queries with parameterized queries. In situations where dynamic queries must be created, never use direct user input, but instead use a map or dictionary of valid values and resolve them using a user supplied key.

For example, some database drivers do not allow parameterized queries for > or < comparison operators. In these cases, do not use a user supplied > or < value, but rather have the user supply a gt or lt value. The alphabetical values are then used to look up the > and < values to be used in the construction of the dynamic query. The same goes for other queries where column or table names are required but cannot be parameterized. Data that is possible user-controlled from a python request is passed to execute() function. To remediate this issue, use SQLAlchemy statements which are built with query parameterization and therefore not vulnerable to sql injection.

If for some reason this is not feasible, ensure calls including user-supplied data pass it in to the params parameter of the execute() method. Below is an example using execute(), passing in user-supplied data as params. This will treat the query as a parameterized query and params as strictly data, preventing any possibility of SQL Injection.

name = request.args.get('name')
req = text('SELECT * FROM student WHERE firstname = :x')
result = db.session.execute(req, {"x":name})

For more information on QuerySets see:

Summary:

SQL Injection Vulnerability Analysis

Reported Vulnerability

The report indicates a potential SQL Injection vulnerability (CWE-89) where user input might be directly concatenated into SQL queries, allowing attackers to manipulate the query structure and potentially access or modify unauthorized data.

Analysis

After examining the code, I've determined this is a false positive. The code is already following security best practices by using parameterized queries throughout the application:

  1. In the /register endpoint:
cursor.execute('INSERT INTO users (username, password, credit_card) VALUES (?, ?, ?)',
               (username, hashed_password, encrypted_credit_card))
  1. In the /login endpoint:
user = cursor.execute('SELECT * FROM users WHERE username = ?', (username,)).fetchone()
  1. In the /user/<int:user_id> endpoint:
user = cursor.execute('SELECT * FROM users WHERE id = ?', (user_id,)).fetchone()

All SQL queries in the code are properly parameterized using the question mark (?) placeholder syntax with SQLite, and the parameters are passed as a separate tuple. This approach ensures that user input is treated as data rather than executable SQL code, effectively preventing SQL injection attacks.

The code is already following the recommended practice mentioned in the vulnerability report of using parameterized queries instead of string concatenation for SQL statements.

Conclusion

No changes are needed as the code is already secure against SQL injection attacks.

Identifiers:

  • A1:2017 - Injection
  • A03:2021 - Injection
  • CWE-89
  • python_flask_rule-flask-tainted-sql-string

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