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How to fix SQL Injection (Legacy & Modern)
in .NET 8 Web API

Executive Summary

SQL Injection remains the king of critical vulnerabilities, even in .NET 8. While Entity Framework Core provides built-in protection, developers frequently bypass it using raw SQL execution for 'performance' or 'legacy compatibility'. In modern .NET, the vulnerability usually manifests when developers treat untrusted input as code rather than data, specifically through string interpolation in raw query executors.

The Vulnerable Pattern

VULNERABLE CODE
// Legacy ADO.NET Vulnerability
string query = "SELECT * FROM Products WHERE Category = '" + category + "'";
var cmd = new SqlCommand(query, connection);

// Modern EF Core Vulnerability (Using FromSqlRaw incorrectly) var products = context.Products .FromSqlRaw($“SELECT * FROM Products WHERE Category = ‘{category}’”) .ToList();

The Secure Implementation

The vulnerability occurs because the database engine cannot distinguish between the SQL command and the user-supplied data. In the vulnerable examples, an attacker can input 'Electronics' OR 1=1--' to dump the entire table. The fix involves Parameterization. In .NET 8, the 'FromSql' method leverages the 'FormattableString' type to automatically convert interpolated strings into safe 'DbParameter' objects. For legacy ADO.NET, explicit 'SqlParameter' usage ensures the DB driver handles escaping and type-checking, stripping the input of its executable context.

SECURE CODE
// Modern EF Core (Automatic Parameterization via FormattableString)
var products = await context.Products
    .FromSql($"SELECT * FROM Products WHERE Category = {category}")
    .ToListAsync();

// Legacy ADO.NET (Explicit Parameterization) var cmd = new SqlCommand(“SELECT * FROM Products WHERE Category = @cat”, connection); cmd.Parameters.Add(new SqlParameter(“@cat”, SqlDbType.NVarChar) { Value = category });

// Dapper (Secure Implementation) var dapperResults = connection.Query(“SELECT * FROM Products WHERE Category = @cat”, new { cat = category });

System Alert • ID: 6956
Target: .NET 8 Web API API
Potential Vulnerability

Your .NET 8 Web API API might be exposed to SQL Injection (Legacy & Modern)

74% of .NET 8 Web API apps fail this check. Hackers use automated scanners to find this specific flaw. Check your codebase before they do.

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