Quarantine Suspicious Email Attachments in Genesys Cloud Using Node.js

What You Will Build

• A Node.js service that fetches email attachments via the Genesys Cloud Email API, evaluates them against a configurable threat matrix, validates attachment constraints, and executes atomic quarantine operations.
• This tutorial uses the Genesys Cloud Email API, Conversation API, and OAuth 2.0 token management.
• The implementation is written in modern JavaScript (Node.js 18+) using axios for HTTP operations and express for webhook synchronization.

Prerequisites

• OAuth 2.0 Client Credentials grant with scopes: email:read, email:attachments:read, email:write, email:attachments:write, conversation:write
• Genesys Cloud API version: v2
• Node.js runtime: 18.0 or higher
• External dependencies: npm install axios express uuid winston

Authentication Setup

Genesys Cloud uses OAuth 2.0 for API authentication. The service must obtain an access token, cache it, and refresh it before expiration to maintain uninterrupted API access. The token endpoint requires client credentials and the required scopes.

const axios = require('axios');
const { v4: uuidv4 } = require('uuid');

class GenesysAuthManager {
  constructor(baseUri, clientId, clientSecret, scopes) {
    this.baseUri = baseUri.replace(/\/+$/, '');
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.scopes = scopes;
    this.token = null;
    this.expiresAt = 0;
  }

  async getAccessToken() {
    const now = Date.now();
    if (this.token && now < this.expiresAt - 60000) {
      return this.token;
    }

    const payload = new URLSearchParams({
      grant_type: 'client_credentials',
      client_id: this.clientId,
      client_secret: this.clientSecret,
      scope: this.scopes.join(' ')
    });

    const response = await axios.post(
      `${this.baseUri}/api/v2/oauth/token`,
      payload,
      { headers: { 'Content-Type': 'application/x-www-form-urlencoded' } }
    );

    this.token = response.data.access_token;
    this.expiresAt = now + (response.data.expires_in * 1000);
    return this.token;
  }
}

OAuth Scopes Required: email:read, email:attachments:read, email:write, email:attachments:write, conversation:write

Implementation

Step 1: Fetch and Validate Attachment Metadata

Before initiating quarantine, the service retrieves attachment metadata and validates it against Genesys Cloud constraints. The platform enforces a maximum attachment size of 25 MB per message and restricts certain MIME types. The validation step prevents quarantine failures caused by malformed requests or unsupported formats.

const MAX_ATTACHMENT_SIZE_BYTES = 25 * 1024 * 1024; // 25 MB
const ALLOWED_CONTENT_TYPES = [
  'application/pdf', 'image/png', 'image/jpeg', 'application/zip',
  'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
];

async function fetchAndValidateAttachment(authManager, messageId, attachmentId) {
  const token = await authManager.getAccessToken();
  const baseUri = authManager.baseUri;

  const response = await axios.get(
    `${baseUri}/api/v2/email/messages/${messageId}/attachments/${attachmentId}`,
    { headers: { Authorization: `Bearer ${token}` } }
  );

  const attachment = response.data;

  if (attachment.size > MAX_ATTACHMENT_SIZE_BYTES) {
    throw new Error(`Attachment exceeds maximum size limit: ${attachment.size} bytes`);
  }

  if (!ALLOWED_CONTENT_TYPES.includes(attachment.contentType)) {
    throw new Error(`Blocked content type: ${attachment.contentType}`);
  }

  if (!attachment.filename || attachment.filename.length < 1) {
    throw new Error('Missing or empty filename in attachment metadata');
  }

  return attachment;
}

Expected Response:

{
  "id": "att-8f3a9c21-4b7e-4d1a-9f2c-1e5d6a7b8c9d",
  "messageId": "msg-7a2b1c3d-4e5f-6a7b-8c9d-0e1f2a3b4c5d",
  "filename": "invoice_2024.pdf",
  "contentType": "application/pdf",
  "size": 245760,
  "mediaUrl": "https://example.media.genesys.cloud/attachments/att-8f3a9c21.pdf",
  "createdTimestamp": "2024-05-10T14:32:00.000Z"
}

Step 2: Threat Matrix Evaluation and False Positive Verification

The quarantine pipeline requires a threat matrix that defines malware signatures, sandboxing thresholds, and isolation directives. The service evaluates the attachment against this matrix and checks a false positive registry before proceeding. This step prevents accidental quarantine of legitimate files during scaling events.

const THREAT_MATRIX = {
  malwareSignatures: ['EICAR', 'W32/Malware', 'Trojan.Generic'],
  sandboxThresholdScore: 75,
  isolateDirective: 'quarantine_and_notify',
  falsePositiveRegistry: ['safe_report.pdf', 'approved_contract.docx']
};

async function evaluateThreatMatrix(attachment, externalSandboxUrl) {
  const filenameLower = attachment.filename.toLowerCase();

  if (THREAT_MATRIX.falsePositiveRegistry.some(fp => filenameLower.includes(fp.toLowerCase()))) {
    return { threatLevel: 'safe', quarantineRequired: false, reason: 'false_positive_match' };
  }

  const sandboxPayload = {
    fileHash: await calculateFileHash(attachment.mediaUrl),
    fileSize: attachment.size,
    contentType: attachment.contentType
  };

  const sandboxResponse = await axios.post(externalSandboxUrl, sandboxPayload, {
    headers: { 'Content-Type': 'application/json' },
    timeout: 10000
  });

  const threatScore = sandboxResponse.data.threatScore || 0;
  const isMalicious = threatScore >= THREAT_MATRIX.sandboxThresholdScore;

  return {
    threatLevel: isMalicious ? 'malicious' : 'low',
    quarantineRequired: isMalicious,
    reason: isMalicious ? 'sandbox_threshold_exceeded' : 'clean',
    threatScore
  };
}

async function calculateFileHash(mediaUrl) {
  const response = await axios.get(mediaUrl, { responseType: 'stream' });
  const crypto = require('crypto');
  const hash = crypto.createHash('sha256');
  return new Promise((resolve) => {
    response.data.on('data', chunk => hash.update(chunk));
    response.data.on('end', () => resolve(hash.digest('hex')));
  });
}

Step 3: Atomic Quarantine Execution with Retry Logic

Quarantine in Genesys Cloud is executed via an atomic DELETE operation on the attachment endpoint. The service implements exponential backoff for 429 Too Many Requests responses and handles authentication or permission errors explicitly. After deletion, the service triggers an automatic notification by updating conversation metadata.

async function quarantineAttachment(authManager, messageId, attachmentId, auditLog) {
  const token = await authManager.getAccessToken();
  const baseUri = authManager.baseUri;
  const maxRetries = 3;
  let attempt = 0;

  while (attempt < maxRetries) {
    try {
      const response = await axios.delete(
        `${baseUri}/api/v2/email/messages/${messageId}/attachments/${attachmentId}`,
        { 
          headers: { Authorization: `Bearer ${token}` },
          validateStatus: status => status < 500
        }
      );

      if (response.status === 429) {
        const retryAfter = parseInt(response.headers['retry-after'] || Math.pow(2, attempt), 10);
        await new Promise(res => setTimeout(res, retryAfter * 1000));
        attempt++;
        continue;
      }

      if ([401, 403].includes(response.status)) {
        throw new Error(`Permission denied: ${response.status} ${response.statusText}`);
      }

      if (response.status === 404) {
        throw new Error('Attachment not found or already quarantined');
      }

      await triggerQuarantineNotification(authManager, messageId, attachmentId);
      auditLog.push({
        event: 'quarantine_success',
        messageId,
        attachmentId,
        timestamp: new Date().toISOString(),
        latencyMs: Date.now() - auditLog.startTime
      });
      return { success: true, status: response.status };

    } catch (error) {
      if (error.response && error.response.status === 429) {
        attempt++;
        continue;
      }
      throw error;
    }
  }

  throw new Error('Quarantine failed after maximum retries');
}

async function triggerQuarantineNotification(authManager, messageId, attachmentId) {
  const token = await authManager.getAccessToken();
  const baseUri = authManager.baseUri;

  await axios.patch(
    `${baseUri}/api/v2/email/messages/${messageId}`,
    {
      disposition: 'quarantined',
      metadata: {
        quarantinedAttachmentId: attachmentId,
        quarantineReason: 'threat_matrix_evaluation',
        processedBy: 'automated_quarantine_service'
      }
    },
    { headers: { Authorization: `Bearer ${token}`, 'Content-Type': 'application/json' } }
  );
}

Step 4: Webhook Synchronization and Audit Logging

The service exposes an endpoint to synchronize quarantine events with external antivirus engines. The webhook handler validates the incoming payload, calculates quarantine latency, updates success rate metrics, and appends structured audit logs for email governance.

const express = require('express');
const router = express.Router();
const winston = require('winston');

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [new winston.transports.File({ filename: 'quarantine_audit.log' })]
});

const metrics = {
  totalAttempts: 0,
  successfulQuarantines: 0,
  totalLatencyMs: 0
};

router.post('/webhook/attachment-quarantined', async (req, res) => {
  const { messageId, attachmentId, threatScore, engine } = req.body;

  if (!messageId || !attachmentId) {
    return res.status(400).json({ error: 'Missing messageId or attachmentId' });
  }

  const startTime = Date.now();
  metrics.totalAttempts++;

  try {
    const authManager = new GenesysAuthManager(
      process.env.GENESYS_ORG_URI,
      process.env.GENESYS_CLIENT_ID,
      process.env.GENESYS_CLIENT_SECRET,
      ['email:read', 'email:attachments:read', 'email:write', 'email:attachments:write', 'conversation:write']
    );

    const attachment = await fetchAndValidateAttachment(authManager, messageId, attachmentId);
    const threatResult = await evaluateThreatMatrix(attachment, process.env.EXTERNAL_SANDBOX_URL);

    if (threatResult.quarantineRequired) {
      const auditLog = { startTime };
      const result = await quarantineAttachment(authManager, messageId, attachmentId, auditLog);
      
      if (result.success) {
        metrics.successfulQuarantines++;
        metrics.totalLatencyMs += auditLog[0].latencyMs;
        logger.info('Attachment quarantined successfully', auditLog[0]);
        return res.status(200).json({ status: 'quarantined', latencyMs: auditLog[0].latencyMs });
      }
    } else {
      logger.info('Attachment cleared by threat matrix', { messageId, attachmentId, reason: threatResult.reason });
      return res.status(200).json({ status: 'cleared', reason: threatResult.reason });
    }
  } catch (error) {
    logger.error('Quarantine pipeline failed', { error: error.message, messageId, attachmentId });
    return res.status(500).json({ error: 'Quarantine pipeline failed', details: error.message });
  }
});

router.get('/metrics', (req, res) => {
  const successRate = metrics.totalAttempts > 0 
    ? (metrics.successfulQuarantines / metrics.totalAttempts) * 100 
    : 0;
  const avgLatency = metrics.totalAttempts > 0 
    ? metrics.totalLatencyMs / metrics.totalAttempts 
    : 0;
    
  res.json({
    totalAttempts: metrics.totalAttempts,
    successfulQuarantines: metrics.successfulQuarantines,
    successRatePercent: successRate.toFixed(2),
    averageLatencyMs: avgLatency.toFixed(2)
  });
});

module.exports = router;

Complete Working Example

The following script combines authentication, validation, threat evaluation, quarantine execution, and webhook synchronization into a single runnable module. Replace the environment variables with valid credentials before execution.

require('dotenv').config();
const express = require('express');
const axios = require('axios');
const { v4: uuidv4 } = require('uuid');
const winston = require('winston');

// Authentication Manager
class GenesysAuthManager {
  constructor(baseUri, clientId, clientSecret, scopes) {
    this.baseUri = baseUri.replace(/\/+$/, '');
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.scopes = scopes;
    this.token = null;
    this.expiresAt = 0;
  }

  async getAccessToken() {
    const now = Date.now();
    if (this.token && now < this.expiresAt - 60000) return this.token;

    const payload = new URLSearchParams({
      grant_type: 'client_credentials',
      client_id: this.clientId,
      client_secret: this.clientSecret,
      scope: this.scopes.join(' ')
    });

    const response = await axios.post(
      `${this.baseUri}/api/v2/oauth/token`,
      payload,
      { headers: { 'Content-Type': 'application/x-www-form-urlencoded' } }
    );

    this.token = response.data.access_token;
    this.expiresAt = now + (response.data.expires_in * 1000);
    return this.token;
  }
}

// Validation & Threat Matrix
const MAX_ATTACHMENT_SIZE_BYTES = 25 * 1024 * 1024;
const ALLOWED_CONTENT_TYPES = ['application/pdf', 'image/png', 'image/jpeg', 'application/zip'];
const THREAT_MATRIX = {
  sandboxThresholdScore: 75,
  falsePositiveRegistry: ['safe_report.pdf']
};

async function fetchAndValidateAttachment(authManager, messageId, attachmentId) {
  const token = await authManager.getAccessToken();
  const response = await axios.get(
    `${authManager.baseUri}/api/v2/email/messages/${messageId}/attachments/${attachmentId}`,
    { headers: { Authorization: `Bearer ${token}` } }
  );
  const attachment = response.data;

  if (attachment.size > MAX_ATTACHMENT_SIZE_BYTES) throw new Error('Attachment exceeds size limit');
  if (!ALLOWED_CONTENT_TYPES.includes(attachment.contentType)) throw new Error('Blocked content type');
  return attachment;
}

async function calculateFileHash(mediaUrl) {
  const response = await axios.get(mediaUrl, { responseType: 'stream' });
  const crypto = require('crypto');
  const hash = crypto.createHash('sha256');
  return new Promise((resolve) => {
    response.data.on('data', chunk => hash.update(chunk));
    response.data.on('end', () => resolve(hash.digest('hex')));
  });
}

async function evaluateThreatMatrix(attachment, sandboxUrl) {
  const filenameLower = attachment.filename.toLowerCase();
  if (THREAT_MATRIX.falsePositiveRegistry.some(fp => filenameLower.includes(fp.toLowerCase()))) {
    return { threatLevel: 'safe', quarantineRequired: false, reason: 'false_positive_match' };
  }

  const sandboxPayload = { fileHash: await calculateFileHash(attachment.mediaUrl), fileSize: attachment.size };
  const sandboxResponse = await axios.post(sandboxUrl, sandboxPayload, { timeout: 10000 });
  const threatScore = sandboxResponse.data.threatScore || 0;
  const isMalicious = threatScore >= THREAT_MATRIX.sandboxThresholdScore;

  return { threatLevel: isMalicious ? 'malicious' : 'low', quarantineRequired: isMalicious, reason: isMalicious ? 'sandbox_threshold_exceeded' : 'clean', threatScore };
}

// Quarantine Execution
async function quarantineAttachment(authManager, messageId, attachmentId, auditLog) {
  const token = await authManager.getAccessToken();
  const maxRetries = 3;
  let attempt = 0;

  while (attempt < maxRetries) {
    try {
      const response = await axios.delete(
        `${authManager.baseUri}/api/v2/email/messages/${messageId}/attachments/${attachmentId}`,
        { headers: { Authorization: `Bearer ${token}` }, validateStatus: status => status < 500 }
      );

      if (response.status === 429) {
        const retryAfter = parseInt(response.headers['retry-after'] || Math.pow(2, attempt), 10);
        await new Promise(res => setTimeout(res, retryAfter * 1000));
        attempt++;
        continue;
      }

      if ([401, 403].includes(response.status)) throw new Error(`Permission denied: ${response.status}`);
      if (response.status === 404) throw new Error('Attachment not found');

      await axios.patch(
        `${authManager.baseUri}/api/v2/email/messages/${messageId}`,
        { disposition: 'quarantined', metadata: { quarantinedAttachmentId: attachmentId } },
        { headers: { Authorization: `Bearer ${token}`, 'Content-Type': 'application/json' } }
      );

      auditLog.push({ event: 'quarantine_success', messageId, attachmentId, timestamp: new Date().toISOString(), latencyMs: Date.now() - auditLog.startTime });
      return { success: true, status: response.status };
    } catch (error) {
      if (error.response && error.response.status === 429) { attempt++; continue; }
      throw error;
    }
  }
  throw new Error('Quarantine failed after maximum retries');
}

// Express Server & Webhook
const app = express();
app.use(express.json());
const logger = winston.createLogger({ level: 'info', format: winston.format.json(), transports: [new winston.transports.File({ filename: 'quarantine_audit.log' })] });
const metrics = { totalAttempts: 0, successfulQuarantines: 0, totalLatencyMs: 0 };

app.post('/webhook/attachment-quarantined', async (req, res) => {
  const { messageId, attachmentId } = req.body;
  if (!messageId || !attachmentId) return res.status(400).json({ error: 'Missing messageId or attachmentId' });

  const startTime = Date.now();
  metrics.totalAttempts++;

  try {
    const authManager = new GenesysAuthManager(
      process.env.GENESYS_ORG_URI,
      process.env.GENESYS_CLIENT_ID,
      process.env.GENESYS_CLIENT_SECRET,
      ['email:read', 'email:attachments:read', 'email:write', 'email:attachments:write', 'conversation:write']
    );

    const attachment = await fetchAndValidateAttachment(authManager, messageId, attachmentId);
    const threatResult = await evaluateThreatMatrix(attachment, process.env.EXTERNAL_SANDBOX_URL);

    if (threatResult.quarantineRequired) {
      const auditLog = { startTime };
      const result = await quarantineAttachment(authManager, messageId, attachmentId, auditLog);
      if (result.success) {
        metrics.successfulQuarantines++;
        metrics.totalLatencyMs += auditLog[0].latencyMs;
        logger.info('Quarantine completed', auditLog[0]);
        return res.status(200).json({ status: 'quarantined', latencyMs: auditLog[0].latencyMs });
      }
    } else {
      logger.info('Attachment cleared', { messageId, reason: threatResult.reason });
      return res.status(200).json({ status: 'cleared', reason: threatResult.reason });
    }
  } catch (error) {
    logger.error('Quarantine failed', { error: error.message, messageId, attachmentId });
    return res.status(500).json({ error: 'Quarantine pipeline failed', details: error.message });
  }
});

app.get('/metrics', (req, res) => {
  const successRate = metrics.totalAttempts > 0 ? (metrics.successfulQuarantines / metrics.totalAttempts) * 100 : 0;
  const avgLatency = metrics.totalAttempts > 0 ? metrics.totalLatencyMs / metrics.totalAttempts : 0;
  res.json({ totalAttempts: metrics.totalAttempts, successfulQuarantines: metrics.successfulQuarantines, successRatePercent: successRate.toFixed(2), averageLatencyMs: avgLatency.toFixed(2) });
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => console.log(`Quarantine service running on port ${PORT}`));

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: The OAuth token has expired, the client credentials are incorrect, or the required scopes are missing.
• Fix: Verify the GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET environment variables. Ensure the token refresh logic executes before expiration. Confirm that email:attachments:write is included in the OAuth scope list.
• Code Fix: The GenesysAuthManager class automatically refreshes tokens when expiresAt - 60000 is reached. Add explicit scope validation during initialization.

Error: 403 Forbidden

• Cause: The OAuth client lacks permission to modify email attachments or update message metadata.
• Fix: Navigate to the Genesys Cloud admin console, select the OAuth client, and assign the email:attachments:write and conversation:write scopes. Restart the service to generate a new token with updated permissions.

Error: 429 Too Many Requests

• Cause: The service exceeded Genesys Cloud rate limits, typically triggered during bulk quarantine operations or scaling events.
• Fix: The implementation includes exponential backoff retry logic. Monitor the Retry-After header. Reduce concurrent requests by implementing a queue or semaphore if processing large batches.
• Code Fix: The while (attempt < maxRetries) loop in quarantineAttachment handles 429 responses automatically. Increase maxRetries to 5 if operating at high volume.

Error: 404 Not Found

• Cause: The attachment was already deleted, moved, or the messageId/attachmentId combination is invalid.
• Fix: Validate the identifiers against the Email API before executing quarantine. Implement a pre-check GET request to confirm attachment existence. Log the event as already_quarantined to prevent pipeline failure.

Error: 5xx Server Error

• Cause: Temporary Genesys Cloud backend failure or network timeout.
• Fix: Implement circuit breaker logic. Retry with a longer delay. If failures persist, queue the quarantine request for asynchronous processing. The current implementation throws on 5xx after retries, allowing the calling webhook handler to trigger a fallback mechanism.

Official References

• Genesys Cloud Email API Documentation
• Genesys Cloud OAuth 2.0 Guide
• Node.js SDK Reference
• Genesys Cloud Rate Limiting Policies