Log Obfuscator

A Winston plugin for obfuscating sensitive data in log messages, including credit cards, SSNs, emails, phone numbers, UUIDs, and Brazilian data formats.

Installation

npm install winston-log-obfuscator

Usage

This package provides a Winston format that obfuscates sensitive data such as credit card numbers, social security numbers, emails, phone numbers, UUIDs, and Brazilian-specific data.

Basic Usage

import * as winston from 'winston';
import { obfuscateFormat } from 'winston-log-obfuscator';

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.combine(
    obfuscateFormat(),
    winston.format.simple()
  ),
  transports: [
    new winston.transports.Console()
  ]
});

logger.info('Payment with card 4111 1111 1111 1111 approved');
// Output: Payment with card **** **** **** **** approved

logger.info('User SSN is 123-45-6789');
// Output: User SSN is XXX-XX-XXXX

logger.info('Contact [email protected] for support');
// Output: Contact ****@example.com for support

logger.info('Call (555) 123-4567');
// Output: Call (XXX) XXX-XXXX

logger.info('UUID: 123e4567-e89b-12d3-a456-426614174000');
// Output: UUID: XXXX****-****-****-****-************

logger.info('Brazilian CPF: 123.456.789-01');
// Output: Brazilian CPF: XXX.XXX.XXX-XX

Configuration

You can customize which types of data to obfuscate and show partial data:

import { obfuscateFormat } from 'winston-log-obfuscator';

const logger = winston.createLogger({
  format: winston.format.combine(
    obfuscateFormat({
      creditCards: true,
      creditCardsShowLast: 4, // Show last 4 digits
      ssn: true,
      ssnShowLast: 4,
      emails: false, // Disable email obfuscation
      phones: true,
      phonesShowLast: 4,
      uuid: true,
      uuidShowLast: 4,
      regions: {
        brazil: {
          cpf: true,
          cnpj: true,
          phones: true,
          boleto: true
        }
      },
      customPatterns: [
        { pattern: /secret/g, replacement: '[REDACTED]' }
      ]
    }),
    winston.format.simple()
  ),
  transports: [new winston.transports.Console()]
});

Supported Formats

Phone Numbers

• (123) 456-7890
• 123-456-7890

Social Security Numbers

• 123-45-6789 (with dashes)
• 123 45 6789 (with spaces)
• SSNs without separators are not obfuscated to avoid false positives

Brazilian Data

• CPF: 123.456.789-01 or 12345678901
• CNPJ: 12.345.678/0001-23 or 12345678000123
• Phone: +55 11 99999-9999 or (21) 8888-8888
• Boleto: 47-digit codes

Obfuscation Options

• creditCards: Obfuscate credit card numbers (default: true)
• creditCardsShowLast: Number of digits to show at the end (default: 0)
• ssn: Obfuscate Social Security Numbers (default: true)
• ssnShowLast: Number of digits to show at the end (default: 0)
• emails: Obfuscate email addresses (default: true)
• emailsShowFirst: Number of characters to show at the start (default: 0)
• phones: Obfuscate phone numbers (default: true)
• phonesShowLast: Number of digits to show at the end (default: 0)
• uuid: Obfuscate UUIDs (default: false)
• uuidShowLast: Number of digits to show at the end (default: 0)
• customPatterns: Array of custom regex patterns to obfuscate
• regions.brazil.cpf: Obfuscate Brazilian CPF numbers (default: true)
• regions.brazil.cpfShowLast: Number of digits to show at the end (default: 0)
• regions.brazil.cnpj: Obfuscate Brazilian CNPJ numbers (default: true)
• regions.brazil.cnpjShowLast: Number of digits to show at the end (default: 0)
• regions.brazil.phones: Obfuscate Brazilian phone numbers (default: true)
• regions.brazil.phonesShowLast: Number of digits to show at the end (default: 0)
• regions.brazil.boleto: Obfuscate Boleto codes (default: true)
• regions.brazil.boletoShowLast: Number of digits to show at the end (default: 0)

API

obfuscateFormat(options?: ObfuscationOptions): winston.Logform.Format

Creates a Winston format that obfuscates sensitive data.

ObfuscationOptions

interface ObfuscationOptions {
  creditCards?: boolean;
  creditCardsShowLast?: number;
  ssn?: boolean;
  ssnShowLast?: number;
  emails?: boolean;
  emailsShowFirst?: number;
  phones?: boolean;
  phonesShowLast?: number;
  uuid?: boolean;
  uuidShowLast?: number;
  customPatterns?: Array<{ pattern: RegExp; replacement: string }>;
  regions?: {
    brazil?: {
      cpf?: boolean;
      cpfShowLast?: number;
      cnpj?: boolean;
      cnpjShowLast?: number;
      phones?: boolean;
      phonesShowLast?: number;
      boleto?: boolean;
      boletoShowLast?: number;
    };
  };
}

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

License

MIT