What Is Email Spoofing?
A technique commonly used in phishing attacks and spam to trick users by sending emails from a forged sender address.
Email Spoofing Definition
Email spoofing is a cyberattack that deceives users by sending malicious emails from forged or trusted accounts. In spoofing attacks, senders typically forge email headers and impersonate credible, recognizable sources such as a colleague, financial institution, or enterprise. Recipients are more likely to click embedded malicious links or open malware attachments. By exploiting the recipient’s trust, the attacker can steal sensitive information. This identity deception technique is widely used in phishing and spam attacks.
How Does Email Spoofing Work?
Generally, the following fields are modified or forged in email spoofing:
- Reply-to: Forged name and email address
- From: Forged name and email address
- Return-path: Forged email address
- Source IP: Illegitimate Internet Protocol (IP) address
Email systems are prone to email spoofing, as outgoing email servers have no way to verify whether the sender's address is spoofed or legitimate. Users must manually review email headers to determine the authenticity of a message.
Spoofing an email requires setting up or compromising a Simple Mail Transfer Protocol (SMTP) server. Attackers then manipulate their email addresses so their phishing messages appear to come from a trusted brand, colleague, or enterprise.
Email spoofing is one of the easiest methods for sending malicious emails, as SMTP—the protocol used to send, receive, and route emails and attachments—lacks an authentication mechanism for verifying sender addresses.
Why Do Scammers Send Spoofed Emails?
Email spoofing can be carried out for several reasons:
- To conceal the sender’s identity
- To avoid spam blacklisting
- To impersonate an individual or enterprise the victim knows
- To obtain sensitive information and gain access to personal assets
- To damage the victim's or the enterprise's reputation
- To commit identity theft
How to Avoid Being a Target of Email Spoofing
One of the best defenses against email spoofing is to remain suspicious and alert. If there’s any doubt about the legitimacy of the email or sender, it’s best to delete the message from your inbox and notify the trusted sender immediately. Also, avoid opening attachments, clicking links within such emails, or entering your login credentials.
Keeping your antivirus or anti-malware software up to date is essential to help prevent email spoofing. You can also report suspicious emails to your security operations center. If your organization lacks a reporting mechanism, contact your IT team to learn about the appropriate procedures. Most organizations also use tools to help prevent account takeovers and enhance account security.
How to Identify a Spoofed Email
There are various ways email spoofing can be carried out. However, the most common method is domain name spoofing. In this type of spoofing, scammers impersonate the display name of the victim while leaving the email address intact.
Scammers can also spoof the entire email address:
To determine whether an email is malicious or legitimate, you must check the email header information. The email header contains a significant amount of tracking data that can help you identify where the message originated and how it traveled across the internet. Outlined below are a few tips to help you identify a spoofed email.
- Confirm the sender's email address matches the display name: Spoofed emails look legitimate at first glance. However, a closer look at the email header can reveal their true origin
- Ensure the “reply-to” header matches the source: When replying to an email, the “reply-to” header is typically hidden and often overlooked when replying to an email. It’s important to verify this address before responding
- Check the “return-path” of the email: This helps you determine the email’s point of origin and the return-path, which may also be forged
Email Spoofing Protection
Your organization must provide training and reporting tools to employees to help protect their accounts against email spoofing attacks. These tools are critical for determining scammers’ identities, inbound attacks, and outbound impersonation. Traditional security controls, such as cloud-based email systems, can detect and block malicious emails containing links or attachments. Organizations should offer identity-based protections to automatically detect, remove, and block phishing attacks, spoofed emails, business email compromise scams, and more.
Standard email authentication protocols can help protect organization and employee accounts against email spoofing.
- Domain Keys Identified Mail (DKIM): This is a standard technical email authentication protocol that enables organizations to protect senders' and recipients' accounts from spoofing, phishing, scams, and other cyberattacks. It uses asymmetric encryption to create a private and public key pair, with the public key published in the Domain Name System (DNS) record. It works by adding a digital signature to the header of an outgoing email. When the receiving server receives the email with the signature in its header, it asks for a unique public key text record saved in the DNS record to verify whether the email was sent from that domain
- Sender Policy Framework (SPF): This is an email authentication protocol designed to protect your domain against spoofing, phishing, and other email-based attacks carried out by spammers. SPF enables organizations to specify the mail servers or IP addresses approved to send emails on their behalf. When the recipient's server receives an email, the DNS records are checked to identify whether the IP address is listed in the SPF record. If it doesn’t fulfill the criteria, the email fails authentication
- Domain-Based Message Authentication, Reporting, and Conformance (DMARC): This also provides email validation to protect domains from unauthorized use such as email spoofing. DMARC helps prevent malicious emails by indicating whether the spoofed email should be accepted or rejected by recipients. This is done in tandem with SPF and DKIM email standards
- Automated identity monitoring tools: These tools are automated to prevent bad actors from accessing your credentials, systems, and data. They monitor employees’ email addresses to prevent data breaches. The tools consist of a history of past breaches with timelines and details to ensure the timely protection of sensitive information. Besides historic exposure checks and email domain watchlists, these tools offer private email address monitoring, IP address monitoring, a comprehensive breach database, domain verification, and more. Some tools can gather logs from various sources, parse their data, and store and centralize it into a commonly readable format so teams can quickly investigate potential threats. Additionally, you can narrow down the logs using advanced features such as visualizations, out-of-the-box filters, and responsive text-based searching for both live and historical events
Prevalence of Email Spoofing
Email spoofing is a significant and growing threat in the cybersecurity landscape, affecting various industries and causing substantial financial and reputational damage.
Trends
- Rise in sophistication: Cybercriminals are becoming more sophisticated in their methods. Advanced techniques, such as domain spoofing and DMARC, are being used to bypass traditional email security measures
- Targeted attacks: Spear phishing, a more targeted form of phishing, is on the rise. These attacks often involve detailed impersonation and can be more difficult to detect. For example, a 2021 study by Proofpoint found that 88% of organizations experienced spear phishing attacks, up from 76% in 2020
Email security measures
- Domain authentication: Implementing domain authentication protocols such as SPF, DKIM, and DMARC can significantly reduce the risk of email spoofing. These technologies help verify the sender's authenticity and can flag or block suspicious emails
- Email reputation: Email reputation services can also play a crucial role in identifying and blocking spoofed emails. These services track the sending history and behavior of email domains, helping to identify potential threats
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