Enterprise Email Security Best Practices: Preventing Data Breaches, BEC and Phishing Attacks

Table of Contents

Introduction to Enterprise Email Security Best Practices

Email continues to be one of the top attack vectors cybercriminals exploit to infiltrate enterprise networks and steal sensitive data. According to recent statistics, phishing scams amount to nearly 1.2% of all emails, totaling 3.4 billion daily. This means that out of every 4,200 emails, at least one is a phishing attempt. Once they gain a foothold into an organization’s infrastructure through email, attackers can move laterally to compromise additional systems and exfiltrate valuable data. Implementing robust email security measures is no longer an option, but a necessity for organizations that want to protect their systems and data. In this article, we provide expert advice on the top enterprise email security best practices that IT teams should implement to secure their email infrastructure and protect against phishing, business email compromise (BEC) and data breaches.

Secure Email Gateways with Advanced Threat Protection

A core component of any email security strategy should be deploying a secure email gateway (SEG) solution. SEGs act as the first line of defense, analyzing all incoming and outgoing email traffic to automatically detect and block threats.

When evaluating SEGs, the capability to detect advanced threats using techniques like sandboxing and machine learning is key. Sandboxing executes suspicious email attachments in a separate, isolated environment to analyze behavior. Machine learning algorithms are trained to recognize new and emerging attack patterns.

Leading SEGs like Proofpoint and Mimecast offer advanced threat protection that leverages sandboxing, machine learning and other techniques to block sophisticated threats like ransomware, zero days and targeted attacks that basic filters miss.

Implement DMARC and DKIM to Prevent Domain Spoofing

To prevent domain spoofing, a technique commonly used in business email compromise scams, implementing DMARC and DKIM email authentication is critical.

On one hand, domain-based Message Authentication, Reporting & Conformance (DMARC) works by allowing you to configure a policy that instructs receiving email servers to reject messages from your domain that fail authentication checks. On the other hand, domainKeys Identified Mail (DKIM) adds a unique digital signature to outbound messages to validate the sender.

With DMARC and DKIM deployed, spoofed messages pretending to come from your company will automatically fail validation checks and be marked as spam or rejected entirely. This prevents your domain from being used in BEC scams targeting customers and partners.

Enforce Multi-Factor Authentication for Email Access

Enforcing multi-factor authentication (MFA) for all email accounts in your organization limits the impact of stolen or leaked credentials. With MFA, users must provide an additional verification method like an authenticator app code or biometrics when logging into email, on top of just a password.

Even if an attacker manages to obtain a user’s login credentials through phishing or a breach, they will not be able to access the account and emails without also gaining control of the user’s MFA credentials. Implementing MFA is one of the most impactful steps for securing email access.

Furthermore, integrating MFA across your organization’s email system significantly enhances overall security posture. This measure not only protects individual accounts but also fortifies the entire email network against potential breaches. As such, MFA serves as a robust shield, safeguarding sensitive data and communications within your enterprise.

Set Up Dedicated Incident Response Procedures for Email Compromise

Despite best efforts, compromise may still occur bypassing controls. Dedicated incident response plans for email compromise are vital.

This includes trained staff who can disable accounts, rollback changes, and implement controls to stop further damage swiftly. Plans should also cover notifying customers if their data gets exposed in a takeover.

Robust response procedures limit damages and prevent small compromises from becoming major incidents. Refine plans based on lessons from real events.

Implement Email Encryption to Secure Sensitive Communications

Encrypting sensitive emails provides added protection. Encryption converts messages to cyphertext only authorized recipients can decrypt with a key.

This protects confidentiality in transit and prevents unauthorized access if intercepted. Compliance frameworks may mandate encryption for related data emails.

Deploying simple tools like Virtru, Proofpoint Encryption, and ZixEncrypt that integrate with email clients enables ubiquitous encryption with minimal training.

Educate Users on Secure Email Practices

Email’s common targeting for phishing demands informed users. Educating employees on best practices is crucial:

  • Avoid clicking links and attachments unless certain of sender legitimacy. Train validation through secondary channels.
  • Check addresses for variations from official domains. Ensure business sender emails get authenticated and scrutinized.
  • Never provide credentials or sensitive information by email. Legitimate companies won’t request these in messages.
  • Watch for urgent requests, threats, and phishing techniques. Train calm, secure handling.
  • Report suspicious messages immediately so security teams can analyze and improve defenses, and identify future threats.

Ongoing awareness training and simulated phishing reinforces practices. Regularly remind staff of their critical prevention role and email risks. Continuous education makes employees adept at identifying and mitigating email threats.

Maintain Software Updates and Patch Management

While not just for email, maintaining software updates and patching for email infrastructure, clients, and operating systems is imperative as unpatched vulnerabilities allow breaches.

Prioritizing critical patches and testing on non-production systems balances security and stability. Automating deployment maintains protection with minimal effort.

Regularly reviewing and updating patch management policies ensures adapting quickly to new threats by staying informed of latest vulnerabilities and vendor release schedules. Address risks proactively.

Limit Email Account Permissions and Access

To limit breach impact, ensure accounts have minimum needed privileges. Most users just need basic access without expanded permissions.

Strictly limit and protect administrative accounts accessing sensitive systems and data with controls like MFA. Limiting unnecessary permissions contributes to layered security.

Moreover, regularly review and adjust permissions as roles change to ensure only necessary access. Continually updating and restricting creates an adaptable security environment that can swiftly respond to potential breaches.

Log and Monitor Email Traffic for Anomalies

By Logging email activity and implementing robust analytics tools, organizations can promptly detect signs of compromised accounts, data exfiltration, and phishing reconnaissance conducted through email channels. Key indicators to watch for include:
  • Unexpected Increase in Email Activity: Monitor for sudden spikes in sent emails or downloads, particularly for individual users. This could signify a compromised account being used to disseminate spam or malware.
  • Unusual Email Timings: Pay attention to emails sent outside of typical working hours. These could indicate that an attacker, possibly in a different time zone, has gained access to an account.
  • Irregular Attachments: Be wary of attachments with unusual file types that do not align with normal business operations. Such attachments might be tools used by attackers to infiltrate your network.
  • Suspicious Email Addresses and Recipients: Look out for emails originating from dubious domains or those sent to an unusually large number of recipients. This is often a tactic used in phishing campaigns.
Furthermore, integrating machine learning algorithms can enhance your anomaly detection capabilities. These algorithms can learn normal email patterns over time and flag deviations more effectively, offering an advanced layer of protection. By continuously analyzing and adapting to new email traffic patterns, your organization can stay ahead of emerging threats and mitigate potential risks proactively.

Partner with a Cybersecurity Firm for Assessments

Implementing robust enterprise email security best practices is crucial for preventing phishing, BEC scams, and data breaches. Although no solution is foolproof, following these expert guidelines will strengthen your defenses against email-borne attacks.

As part of our penetration testing services, Vumetric can conduct highly targeted simulated phishing attacks against your organization to evaluate defenses. We take care to isolate test infrastructure and minimize collection of unnecessary personal details. Our team informs IT staff before launching campaigns and provides clear scoping.

Additionally, we provide tailored recommendations that leverage any vulnerabilities identified through phishing for improvement. Our goal is to strengthen your email security posture while avoiding business disruptions.

With email being a leading attack vector, implementing these comprehensive enterprise email security best practices is crucial for preventing phishing, BEC scams and data breaches. For assistance securing your email environment and training employees, contact our experts to discuss your needs. We can help implement controls tailored to your specific infrastructure and risks.
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