PHPStan SensitiveParameter Detector

A PHPStan extension that detects parameters that might contain sensitive information and should be marked with the #[\SensitiveParameter] attribute (added in PHP 8.2+).

About SensitiveParameter

The #[\SensitiveParameter] attribute was introduced in PHP 8.2 to mark sensitive data that should be hidden from stack traces and debugging output. This extension helps you identify parameters that should use this attribute for better security.

Learn more: PHP RFC: Redact parameters in back traces

Requirements

• PHP 8.2 or higher
• PHPStan 2.0 or higher

Installation

composer require --dev built-fast/phpstan-sensitive-parameter

Usage

The extension will be automatically registered if you use PHPStan's extension installer.

Alternatively, include the extension in your PHPStan configuration:

includes:
    - vendor/built-fast/phpstan-sensitive-parameter/extension.neon

What it detects

The rule detects parameters with names containing common sensitive keywords:

• Authentication: password, secret, token, credential, auth, bearer
• API Security: apikey (matches apisecret, clientsecret via secret)
• Financial: credit, card, ccv, cvv, ssn, pin
• Security: private, signature, hash, salt, nonce, otp, passcode, csrf

Note: Due to substring matching, secret catches apisecret/clientsecret and token catches refreshtoken/accesstoken.

It works with:

• Regular functions
• Class methods (public, private, protected, static)
• Constructors
• Case-insensitive matching (Password, SECRET, etc.)
• Partial matches (userPassword, secretKey, etc.)

Examples

❌ Will trigger warnings:

function login(string $username, string $password) {
    // Parameter $password should use #[\SensitiveParameter]
}

class AuthService {
    public function setCredentials(string $apikey, string $secret) {
        // Both $apikey and $secret should be marked sensitive
    }
}

✅ Properly protected:

// Function-level protection
#[\SensitiveParameter]
function login(string $username, string $password) {
    // All parameters are protected
}

// Parameter-level protection
function authenticate(
    string $username,
    #[\SensitiveParameter] string $password
) {
    // Only $password is protected
}

// Mixed protection
class AuthService {
    public function verify(
        #[\SensitiveParameter] string $token,
        string $userId,
        string $apikey  // This will still trigger a warning
    ) {
        // $token is protected, $apikey needs protection
    }
}

Advanced Configuration

To use custom sensitive keywords instead of the defaults, override the service:

includes:
    - vendor/built-fast/phpstan-sensitive-parameter/extension.neon

services:
    # Override the default service with custom keywords
    -
        class: BuiltFast\Rules\SensitiveParameterDetectorRule
        arguments:
            - ['password', 'apikey', 'token', 'banking', 'medical']  # Your custom keywords
        tags:
            - phpstan.rules.rule

This completely replaces the default keyword list with your own.

Suppressing Warnings

You can suppress warnings using PHPStan's ignore comments:

// @phpstan-ignore-next-line sensitiveParameter.missing
function legacyFunction(string $password) {
    // Legacy code that cannot be updated
}

// @phpstan-ignore-next-line sensitiveParameter.missing
function anotherLegacyFunction(string $secret) {
    // Another legacy function
}

function modernFunction(string $password): void // @phpstan-ignore-line sensitiveParameter.missing
{
    // Function with inline ignore comment
}

Constructor Parameters

Due to a PHPStan limitation, ignore comments for constructor parameters must be placed before the constructor:

// @phpstan-ignore-next-line sensitiveParameter.missing
public function __construct(
    private readonly SomeService $serviceWithSensitiveKeywordInName
) {}

Note: This ignores ALL parameter warnings for that constructor. For functions with multiple parameters where only some are false positives, consider renaming the problematic parameter to avoid the sensitive keyword match.

Common Issues

False Positives

The rule uses substring matching, which can occasionally trigger false positives:

• $appInstall triggers due to "install" containing "pin"
• $passwordService triggers due to containing "password"
• $signatureMethod triggers due to containing "signature"

For these cases, use ignore comments as shown above or consider renaming parameters to be more specific (e.g., $applicationToInstall, $authService, $verificationMethod).

Reporting Issues

Found a bug or have a feature request? Please report it on GitHub.

When reporting issues, please include:

• PHP version
• PHPStan version
• Code sample that demonstrates the issue
• Expected vs actual behavior

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

Development setup:

git clone https://github.com/built-fast/phpstan-sensitive-parameter.git
cd phpstan-sensitive-parameter
composer install

Running tests:

vendor/bin/pest             # Run tests
vendor/bin/phpstan analyze  # Static analysis
vendor/bin/pint --test      # Code style check

License

MIT License - see LICENSE for details.