Email Security Policy

## Why Email Security Matters

Email remains the primary business communication channel and the #1 attack vector for cybercriminals. Despite advances in security technology, email-based attacks continue to grow in volume and sophistication, threatening organizations of all sizes.

The statistics are sobering:

**According to Verizon's 2024 Data Breach Investigations Report:**

- 36% of all data breaches involved phishing

- 94% of malware is delivered via email

- Business Email Compromise (BEC) attacks resulted in $2.9 billion in losses in 2023

**IBM's 2024 Cost of a Data Breach Report found:**

- Email is the initial attack vector in 16% of breaches

- Average cost of an email-based breach: $4.9 million

- Mean time to identify email-based attacks: 277 days

**Real-World Email Security Incidents:**

**2023 MGM Resorts Attack:** Attackers called the help desk pretending to be an employee found on LinkedIn, reset credentials via email, and gained initial access that led to a $100 million ransomware attack.

**2022 Uber Breach:** An attacker purchased stolen credentials on the dark web, overwhelmed an employee with multi-factor authentication prompts, then convinced them via WhatsApp to approve access. Email was the primary communication channel for the social engineering attack.

**Ongoing Business Email Compromise (BEC):** The FBI reports BEC scams targeting finance departments continue to grow. Attackers impersonate CEOs via spoofed emails requesting urgent wire transfers. Average loss per incident: $120,000.

Email security isn't just about blocking spam—it's a comprehensive program addressing:

**Threat Prevention:**

- Phishing and spear-phishing attacks

- Malware and ransomware delivery

- Business Email Compromise (BEC)

- Credential harvesting

- Email spoofing and impersonation

**Data Protection:**

- Preventing accidental data leaks

- Encrypting sensitive information in transit

- Data Loss Prevention (DLP) controls

- Secure email archiving and retention

**Compliance Requirements:**

- HIPAA (healthcare email security)

- GDPR (EU data protection)

- SOX (financial records retention)

- PCI-DSS (payment card data protection)

- State privacy laws (CCPA, VCDPA, etc.)

**Legal and Reputational Protection:**

- Monitoring for policy violations

- Documenting email communications

- Reducing liability exposure

- Protecting brand reputation

## The Email Threat Landscape

### 1. Phishing Attacks

Phishing uses fraudulent emails that appear to be from legitimate sources to steal credentials, install malware, or manipulate recipients into taking harmful actions.

**Traditional Phishing:**

Mass campaigns targeting thousands of recipients with generic messages claiming to be from banks, package delivery services, or popular websites.

Example: "Your Amazon package couldn't be delivered. Click here to reschedule." Link leads to credential harvesting site.

**Spear Phishing:**

Targeted attacks against specific individuals or organizations using researched information to appear authentic.

Example: Attacker researches CFO on LinkedIn, identifies recent conference attendance, sends email appearing to be from conference organizer with malicious attachment labeled "Updated Speaker Schedule."

**Whaling:**

High-value phishing targeting C-level executives, often impersonating board members, external counsel, or regulators.

Example: Email to CEO appearing to be from external legal counsel: "Urgent: Confidential legal matter requires immediate review" with malicious PDF attachment.

**Clone Phishing:**

Attackers intercept legitimate email conversations, clone a previous message, replace links/attachments with malicious versions, and resend from spoofed address.

**Credential Harvesting:**

Fake login pages mimicking Microsoft 365, Google Workspace, or corporate VPN portals designed to capture usernames and passwords.

**Phishing Success Factors:**

- Urgency: "Your account will be locked in 24 hours"

- Authority: Impersonating executives or IT department

- Curiosity: "You received a secure message"

- Fear: "Suspicious activity detected on your account"

- Greed: "You've won a prize" or fake payment notifications

### 2. Business Email Compromise (BEC)

BEC attacks use spoofed or compromised email accounts to manipulate employees into transferring money or sensitive data.

**Common BEC Scenarios:**

**CEO Fraud (Whaling):**

Attacker impersonates CEO emailing finance department: "I'm in a meeting with our M&A advisor. Wire $250,000 to escrow account immediately. Details attached. Keep this confidential."

**Vendor Email Compromise:**

Attacker compromises legitimate vendor email account or spoofs vendor address with similar domain. Sends updated banking information for upcoming payment, redirecting funds to attacker-controlled account.

**Attorney Impersonation:**

Email appearing to be from external counsel requesting urgent wire transfer for settlement, licensing fee, or regulatory payment.

**Payroll Diversion:**

Attacker impersonates employee requesting change to direct deposit information, redirecting paycheck to attacker's account.

**W-2 Phishing:**

HR departments targeted with CEO impersonation requesting all employee W-2 forms for "tax planning." Results in mass identity theft exposure.

**BEC Prevention Strategies:**

- Out-of-band verification for financial transactions (phone call to known number)

- Dual authorization for wire transfers above threshold

- Alert on external emails from executive-sounding names

- Training finance teams to recognize social engineering

- Strict procedures for banking information changes

### 3. Malware and Ransomware Delivery

Email is the primary delivery mechanism for malicious software.

**Attachment-Based Malware:**

- **Office Macros:** Malicious Excel/Word files with macros that download malware

- **ZIP Archives:** Password-protected archives bypass some scanners

- **PDF Exploits:** Malicious PDFs exploiting reader vulnerabilities

- **Script Files:** .js, .vbs, .ps1 files that execute when opened

- **Executable Disguises:** evil.pdf.exe relies on Windows hiding extensions

**Link-Based Malware:**

- Links to compromised legitimate websites hosting exploit kits

- Google Drive/OneDrive sharing links to malicious files (appears safe)

- URL shorteners hiding final destination

- Redirector chains to evade detection

**Ransomware Campaigns:**

Emotet, Ryuk, LockBit, and other ransomware families commonly delivered via email. Initial access broker compromises email account, performs reconnaissance, then deploys ransomware to maximum number of systems.

### 4. Email Spoofing and Impersonation

Attackers forge email headers to make messages appear from trusted sources.

**Display Name Spoofing:**

Email from "John Smith - CEO <attacker@gmail.com>" appears in many clients as simply "John Smith - CEO" hiding the actual address.

**Domain Spoofing:**

Without SPF/DKIM/DMARC protections, attackers can send email claiming to be from yourcompany.com even though it originated elsewhere.

**Look-Alike Domains:**

- yourcompany.com vs. your-company.com

- yourcompany.com vs. yourcompany.co

- yourcompany.com vs. yourconpany.com (m replaced with n)

**Compromised Accounts:**

Legitimate user account credentials stolen via phishing, then used to send malicious emails from within the organization (bypasses external email warnings).

## Email Security Technologies

### 1. Email Authentication Protocols

**SPF (Sender Policy Framework):**

DNS record listing IP addresses authorized to send email for your domain. Receiving servers check if incoming email originated from authorized IPs.

Example SPF Record:

v=spf1 ip4:192.0.2.0/24 include:_spf.google.com -all

Translation: Only mail servers at 192.0.2.0/24 and Google Workspace servers can send email for this domain. Reject all others (-all).

**Benefits:** Prevents domain spoofing, improves deliverability

**Limitation:** Breaks when email is forwarded (forwarding server IP not authorized)

**DKIM (DomainKeys Identified Mail):**

Cryptographic signature attached to email headers. Receiving server validates signature using public key published in DNS.

**Benefits:** Proves email wasn't altered in transit, survives forwarding

**Limitation:** Doesn't prevent look-alike domains

**DMARC (Domain-based Message Authentication, Reporting and Conformance):**

Policy layer on top of SPF and DKIM. Tells receiving servers what to do when authentication fails and where to send reports.

Example DMARC Record:

v=DMARC1; p=reject; rua=mailto:dmarc-reports@yourcompany.com; pct=100

Translation: If email fails SPF and DKIM checks, reject it. Send aggregate reports to dmarc-reports@yourcompany.com. Apply to 100% of messages.

**DMARC Policies:**

- **p=none:** Monitor only, don't reject (initial deployment phase)

- **p=quarantine:** Send failing messages to spam folder

- **p=reject:** Reject failing messages completely (full protection)

**Implementation Path:**

1. Deploy SPF and DKIM for your domain

2. Set DMARC to p=none, monitor reports for 2-4 weeks

3. Fix any legitimate email sources failing authentication

4. Move to p=quarantine for 2-4 weeks

5. Move to p=reject for full protection

### 2. Email Encryption

**Transport Layer Security (TLS):**

Encrypts email in transit between mail servers. Prevents eavesdropping on network traffic.

Configuration: Opportunistic TLS (upgrade to encryption if available) or forced TLS (require encryption or reject).

**Benefits:** Easy to implement, transparent to users

**Limitations:** Email unencrypted at rest on servers, doesn't protect against server compromise

**S/MIME (Secure/Multipurpose Internet Mail Extensions):**

End-to-end encryption using digital certificates. Email encrypted on sender's device, only decryptable by recipient's private key.

**Use Cases:**

- Healthcare (HIPAA-protected health information)

- Legal (attorney-client privileged communications)

- Financial (sensitive financial data)

- Executives (confidential strategic communications)

**Implementation Requirements:**

- PKI infrastructure or certificate authority

- Certificate deployment to users

- User training on encrypted email

- Key management and recovery procedures

**PGP/GPG (Pretty Good Privacy):**

Open-source end-to-end encryption alternative to S/MIME. Less common in enterprise due to complexity but strong security.

**Portal-Based Encryption:**

Encrypted email delivered as notification with link to secure web portal. Recipient logs in to read message.

**Benefits:** No recipient software required, works with external partners

**Limitations:** Poor user experience, training required

### 3. Advanced Threat Protection

**Sandbox Analysis:**

Suspicious attachments and links executed in isolated virtual environment to observe behavior before delivery.

**URL Rewriting:**

Security service rewrites URLs in email to route through scanning proxy. When user clicks, link is checked in real-time for malicious content.

**Impersonation Protection:**

Machine learning analyzes sender patterns (domain age, display name vs. email address, sending IP reputation, historical communication patterns) to identify impersonation attempts.

**Account Takeover Detection:**

Monitors for unusual sending behavior indicating compromised account:

- Email sent to unusual recipients

- Messages sent outside normal hours

- Forwarding rules created

- Large volume of messages suddenly sent

**Attachment Sandboxing:**

Files executed in virtual environment, monitored for malicious behavior (registry modifications, network connections, file encryption attempts).

### 4. Data Loss Prevention (DLP)

DLP for email scans outbound messages for sensitive data and enforces policies.

**Content Detection Methods:**

**Pattern Matching:**

Detect Social Security numbers (XXX-XX-XXXX), credit card numbers (regex pattern matching Luhn algorithm), account numbers, etc.

**Keyword Dictionaries:**

Custom word lists (project code names, "confidential," "proprietary," medical terms).

**Document Fingerprinting:**

Create hash of sensitive documents (financial reports, customer lists). Detect when emailed even if renamed or partially modified.

**Machine Learning Classification:**

AI models trained to identify sensitive content based on context, not just keywords.

**DLP Policy Actions:**

- **Block:** Prevent email from being sent

- **Quarantine:** Hold for manager approval

- **Encrypt:** Automatically encrypt messages containing sensitive data

- **Warn:** Alert sender with option to proceed

- **BCC:** Send copy to compliance officer

- **Strip:** Remove attachment, deliver message

**Common DLP Policies:**

- Block SSN/credit card numbers to external recipients

- Encrypt email containing "confidential" to external domains

- Require manager approval for financial spreadsheets sent externally

- Alert CISO when source code emailed outside organization

- Block patient health information to non-healthcare domains

## Email Security Best Practices

### User Security Awareness Training

**Phishing Simulation Programs:**

Send simulated phishing emails to employees, track who clicks, provide immediate training to those who fall for simulation.

**Best Practice Cadence:**

- Monthly simulated phishing campaigns

- Quarterly security awareness training

- Immediate remedial training for repeat clickers

- Annual comprehensive security review

**Effective Training Topics:**

- How to identify phishing indicators (urgency, generic greetings, mismatched URLs)

- Hover over links to preview destination (but don't trust completely—can be spoofed)

- Verify unexpected requests via separate channel (phone, chat, walk over)

- Report suspicious email to security team

- Never provide credentials via email

**Reporting Mechanisms:**

Deploy "Report Phishing" button in email client. Makes reporting easy, provides security team real-time threat intelligence.

### Email Account Security

**Multi-Factor Authentication (MFA):**

Require MFA for all email accounts. Compromised passwords alone can't access account.

**Recommended MFA Methods:**

1. Hardware security keys (YubiKey, Titan)

2. Authenticator apps (Microsoft Authenticator, Google Authenticator)

3. Push notifications (approve/deny)

4. SMS (only if nothing else available—vulnerable to SIM swapping)

**Password Requirements:**

Integrate with password policy (see Password Management Policy). Minimum 12 characters, password manager encouraged.

**Conditional Access:**

Require MFA for email access from:

- Unknown/untrusted devices

- Unusual geographic locations

- High-risk countries

- Anonymous proxy/VPN services

### Email Retention and Archiving

**Retention Requirements:**

**Legal/Regulatory:**

- SOX (Sarbanes-Oxley): 7 years for financial communications

- FINRA: 3-6 years for securities industry

- HIPAA: 6 years for healthcare

- Litigation holds: Indefinite retention when litigation anticipated

**Best Practice:**

- General business email: 3-7 years

- Executive communications: 7 years

- HR/employment records: Duration of employment + 7 years

- Contracts and legal: Perpetual or 7+ years

- Ephemeral/casual: 90 days to 1 year

**Archiving Solutions:**

**Cloud-Native Archiving:**

- Microsoft 365 Archiving and eDiscovery

- Google Vault

- Built-in compliance and legal hold features

**Third-Party Archiving:**

- Mimecast

- Proofpoint

- Barracuda

- Archive messages in tamper-proof format for litigation

**Benefits:**

- Legal discovery and eDiscovery

- Compliance with retention regulations

- Reduce mailbox sizes (performance)

- Recover deleted items beyond retention period

### Mobile Email Security

**Mobile Device Management (MDM):**

Enforce security policies on mobile devices accessing corporate email:

- Device encryption required

- PIN/passcode complexity requirements

- Remote wipe capability

- Containerization (separate work/personal data)

**Email Client Restrictions:**

- Require corporate email app (managed Outlook, Gmail)

- Prohibit unmanaged email clients

- Disable "Open in..." to prevent data leakage

- Block copy/paste from corporate email to personal apps

**Mobile-Specific Risks:**

- Smaller screens harder to identify phishing

- Touch interfaces increase accidental clicks

- Public Wi-Fi exposure (mitigated by TLS)

- Lost/stolen devices

## Compliance and Regulatory Requirements

### GDPR (General Data Protection Regulation)

Email security implications:

- **Data Protection:** Email containing personal data must be appropriately secured

- **Breach Notification:** Email-based breaches must be reported within 72 hours

- **Data Retention:** Email can't be retained longer than necessary

- **Right to Erasure:** Ability to delete individual's emails upon request

- **Data Transfer:** Restrictions on emailing personal data outside EU

### HIPAA (Health Insurance Portability and Accountability Act)

**Email Requirements for ePHI:**

- Encryption required for ePHI transmitted via email

- Access controls limiting who can send/receive ePHI

- Audit trails of ePHI access via email

- Business Associate Agreements with email service providers

**Acceptable Approaches:**

- End-to-end encryption (S/MIME, PGP)

- Encrypted portal delivery

- TLS with encryption at rest (Azure Rights Management, Google Workspace encryption)

### SOX (Sarbanes-Oxley Act)

Email retention for financial communications:

- 7-year retention for financial records

- Immutable archives (prevent alteration)

- eDiscovery capabilities for audits

- Access controls to archived financial emails

### PCI-DSS (Payment Card Industry Data Security Standard)

**Email Prohibitions:**

- NEVER send unencrypted cardholder data via email

- Block credit card numbers in outbound email (DLP)

- Encrypt if cardholder data must be emailed

- Regular security awareness training on protecting payment data

## Implementation Guide: Building Email Security Program

### Phase 1: Foundation (Month 1-2)

**1. Deploy Email Authentication**

- Implement SPF records for all sending domains

- Enable DKIM signing on all outbound email

- Deploy DMARC in monitoring mode (p=none)

- Monitor DMARC reports, fix failing senders

**2. Document Email Security Policy**

- Define acceptable use (business vs. personal)

- Clarify monitoring and privacy expectations

- Establish prohibited uses

- Define enforcement procedures

- Get legal/HR review and approval

**3. Enable Basic Security Controls**

- Ensure spam filtering enabled

- Verify malware scanning active

- Enable multi-factor authentication for all users

- Deploy "Report Phishing" button

**Deliverables:**

- SPF/DKIM/DMARC deployed

- Email security policy documented and published

- MFA enforced

- Baseline security controls operational

### Phase 2: Advanced Threat Protection (Month 2-4)

**1. Deploy Advanced Email Security**

- Implement advanced threat protection (ATP) or secure email gateway

- Enable URL rewriting and time-of-click protection

- Configure attachment sandboxing

- Deploy anti-impersonation rules

**2. Launch Security Awareness Program**

- Conduct baseline security awareness training

- Deploy phishing simulation platform

- Send first simulated phishing campaign

- Provide immediate training to click victims

**3. Strengthen DMARC Policy**

- Move from p=none to p=quarantine

- Monitor for legitimate email failures

- Fix any remaining authentication issues

- Plan migration to p=reject

**Deliverables:**

- Advanced email security operational

- Phishing simulation program running

- DMARC quarantine policy active

- Measurable reduction in click rates

### Phase 3: Data Protection (Month 4-6)

**1. Deploy Email Encryption**

- Select encryption approach (S/MIME, portal, automatic)

- Obtain certificates or configure portal

- Deploy encryption to pilot group

- Train users on encryption usage

- Roll out to all users

**2. Implement Data Loss Prevention**

- Define sensitive data types (SSN, credit cards, confidential documents)

- Create DLP policies for outbound email

- Start in monitor mode, collect data

- Enable enforcement for critical policies (block credit cards)

- Gradually expand DLP coverage

**3. Email Archiving and Retention**

- Define retention requirements by email type

- Select archiving solution

- Deploy archiving for all email

- Configure retention policies

- Test legal hold and eDiscovery

**Deliverables:**

- Email encryption deployed

- DLP preventing data leakage

- Compliant email archiving operational

- Documentation of retention schedule

### Phase 4: Optimization and Maturity (Ongoing)

**1. Continuous Improvement**

- **Monthly:** Review phishing simulation results, adjust difficulty

- **Quarterly:** Analyze email security incidents and trends

- **Quarterly:** DLP policy tuning (reduce false positives)

- **Semi-Annual:** Email security policy review

- **Annual:** Third-party email security assessment

**2. Advanced Capabilities**

- Account compromise detection and auto-remediation

- Integration with SIEM for correlation

- Threat intelligence integration

- Automated incident response workflows

## Email Security Tools and Platforms

**Email Security Gateways / Advanced Threat Protection:**

- **Cloud Services:** Proofpoint, Mimecast, Barracuda, Cisco IronPort

- **Microsoft 365:** Defender for Office 365 (built-in ATP)

- **Google Workspace:** Advanced Protection Program

- **Open Source:** SpamAssassin (basic spam filtering)

**Phishing Simulation and Training:**

- KnowBe4

- Proofpoint Security Awareness Training

- Cofense PhishMe

- Microsoft Attack Simulation Training (included in M365 E5)

**Email Archiving:**

- Mimecast

- Proofpoint Essentials Archive

- Barracuda Email Archiving

- Microsoft Purview (M365 native)

- Google Vault (Workspace native)

**Email Encryption:**

- Microsoft Azure Information Protection

- Cisco Registered Envelope Service

- Virtru

- Proofpoint Essentials Encryption

- ZixCorp

## Getting Started with the Template

The Email Security Policy Template provides a complete framework for immediate deployment:

**What's Included:**

1. **Core Email Security Policy Document**

- Purpose and scope (device-neutral coverage)

- Five essential rules (ownership, monitoring, scanning, disclosure, prohibited use)

- Legal provisions and monitoring rights

- Enforcement and non-compliance procedures

2. **Technical Security Standards**

- Email authentication requirements (SPF, DKIM, DMARC)

- Encryption requirements for sensitive data

- DLP policy guidelines

- Acceptable attachment types

3. **User Guidelines**

- How to identify phishing emails

- When to encrypt email

- External email communication standards

- Reporting suspicious messages

4. **Implementation Checklist**

- Technical controls deployment

- User training requirements

- Policy communication plan

- Compliance monitoring

5. **Incident Response Procedures**

- Phishing email reported—what happens next

- Compromised account response

- Data leak via email procedures

- BEC attempt response

**How to Implement:**

1. **Download and Review** the policy template

2. **Customize** for your organization (company name, specific prohibitions, enforcement)

3. **Legal/HR Review** especially monitoring provisions and enforcement

4. **Deploy Technical Controls** (MFA, spam filtering, DMARC)

5. **Communicate Policy** to all employees with training

6. **Launch Awareness Program** with phishing simulations

7. **Monitor Compliance** through regular audits and metrics

8. **Update Annually** based on threat landscape evolution

Whether you're creating your first email security policy or updating an existing program, this template provides the structure, legal protections, and technical guidance to secure your organization's primary communication channel.

Email security is a continuous program, not a one-time project. The threat landscape evolves constantly—your defenses must evolve too. This template gives you the foundation to build a mature, comprehensive email security program that protects your organization from the #1 attack vector.

Your email is your risk. Protect it with a comprehensive, enforceable email security policy.