What is email spoofing?

Email spoofing

Email spoofing is a technique attackers use to forge email headers, making messages appear to come from someone the recipient trusts. The sender's address looks legitimate, but the email actually originates from a malicious source. This deception powers phishing campaigns, business email compromise schemes, and spam operations that bypass traditional filters.

The vulnerability exists because email protocols weren't designed with authentication in mind. When you send an email, the system doesn't verify that you actually own the address in the "From" field. Attackers exploit this gap to impersonate executives, vendors, banks, and colleagues.

How email spoofing works

Every email contains two sets of addressing information: the envelope (used by servers to route the message) and the header (what you see in your inbox). These don't have to match, and receiving servers don't automatically verify them.

An attacker can manipulate several header fields to create a convincing forgery:

• From: The display name and email address shown to recipients
• Reply-To: Where responses get directed, often a different address the attacker controls
• Return-Path: The address that receives bounce notifications

The Simple Mail Transfer Protocol (SMTP) accepts whatever sender information it receives. Without additional authentication checks, a spoofed message sails through to the inbox looking perfectly legitimate.

Why attackers use email spoofing

Spoofing serves multiple criminal objectives, with financial fraud topping the list. An email appearing to come from your CEO requesting an urgent wire transfer carries weight that a random stranger's request never would.

Credential theft follows close behind. Messages that look like they're from your bank or IT department prompt recipients to enter passwords on fake login pages. Attackers also use spoofing to distribute malware through attachments that seem safe because they appear to come from known contacts.

Beyond direct attacks, spoofing helps criminals evade spam blacklists. By rotating through forged sender addresses, they avoid the reputation penalties that would otherwise block their messages.

Email spoofing vs. phishing

These terms often appear together, but they describe different things. Spoofing is a technique for disguising the sender's identity, while phishing is a broader attack strategy aimed at stealing information or installing malware.

Phishing campaigns frequently use spoofed emails as their delivery mechanism. However, not every spoofed email is a phishing attempt, and phishing can occur without spoofing. An attacker might register a lookalike domain (amaz0n.com instead of amazon.com) rather than forging headers directly.

The distinction matters for defense. Technical controls like DMARC address spoofing specifically, while anti-phishing measures focus on detecting malicious content and links regardless of how the email arrived.

How to identify a spoofed email

Spoofed messages often contain subtle inconsistencies that reveal their true origin. Train yourself to notice these warning signs before clicking anything.

Check the actual email address, not just the display name. A message might show "Amazon Support" but come from support@amaz0n-orders.net. Hover over or tap the sender name to reveal the full address.

Examine the email header for authentication results. In Gmail, click the three-dot menu and select "Show original." Look for SPF, DKIM, and DMARC results. Multiple "fail" statuses indicate a likely forgery.

Watch for mismatched domains. If the "From" address shows one company but links point to a completely different domain, something's wrong.

Question urgent requests. Attackers create pressure to prevent careful thinking. Any email demanding immediate action on financial matters or login credentials deserves extra scrutiny.

How to protect your domain from being spoofed

Three authentication protocols work together to prevent attackers from impersonating your domain. Implementing all three significantly reduces the risk that criminals can send emails pretending to be your organization.

SPF (Sender Policy Framework) publishes a list of servers authorized to send email on your domain's behalf. Receiving servers check whether incoming messages originate from approved sources.

DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outgoing messages. Recipients can verify the signature against a public key in your DNS records, confirming the message wasn't altered in transit.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties SPF and DKIM together with a policy telling receivers what to do when authentication fails. You can instruct them to reject, quarantine, or monitor suspicious messages.

ActiveCampaign provides a DKIM, SPF, and DMARC verification tool to check your current configuration and identify gaps.

Protecting your organization from spoofed emails

Technical controls catch many spoofing attempts, but human judgment remains essential. Layer these defenses for comprehensive protection.

Deploy email security tools that scan incoming messages for authentication failures, suspicious links, and known malware signatures. Modern solutions use machine learning to detect anomalies that rule-based filters miss.

Establish verification procedures for sensitive requests. Before transferring funds or sharing confidential data, confirm the request through a separate channel like a phone call to a known number.

Train employees regularly on recognizing spoofing attempts. Show real examples of attacks your organization has received, and make reporting suspicious emails easy and judgment-free.

Keep systems updated to patch vulnerabilities attackers might exploit after gaining initial access through a spoofed email.

FAQs

Is email spoofing illegal?
Spoofing itself exists in a legal gray area, but using it for fraud, identity theft, or distributing malware violates laws in most jurisdictions. The CAN-SPAM Act prohibits deceptive header information in commercial emails.

Can spoofed emails be traced?
Sometimes. Full email headers contain routing information that may reveal the true origin. However, sophisticated attackers use compromised servers, VPNs, and other techniques to obscure their tracks.

Why do I receive spoofed emails from my own address?
Attackers sometimes forge your address in the "From" field to bypass filters or create alarm. This doesn't mean your account was compromised. Implementing DMARC with a reject policy prevents these messages from reaching others who have also configured DMARC.

How do I report spoofed emails?
Forward suspicious messages to your IT security team and to the organization being impersonated. Most companies have dedicated addresses like abuse@ or phishing@ for these reports.

Protecting your email deliverability starts with proper authentication. Ready to verify your domain's security settings? Try ActiveCampaign free and access our built-in authentication tools.