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What is whaling phishing and how can you prevent it?

By Samuel ChenardAugust 11, 20268 min read

In brief

Whaling phishing is a targeted impersonation attack against executives or people who can approve payments. Learn how to verify and reduce the risk.

What is whaling phishing and how can you prevent it?

Whaling phishing is a targeted impersonation attack that uses the authority of an executive or other senior official to pressure someone into sending money, disclosing sensitive information, or changing business details. It is a form of spear phishing, often associated with business email compromise. Prevent it with an out-of-band verification rule for high-risk requests, account security, and email authentication that limits spoofing of your own domain.

At a glance

Quick takeaways

  • Whaling phishing targets executives, executive assistants, finance staff, and other people who can approve sensitive actions.
  • A message can impersonate a leader through a lookalike address, a forged From domain, or a compromised legitimate mailbox.
  • Urgency, secrecy, changed payment details, and a request to bypass normal approval are warning signs.
  • Verify payment, banking, credential, and sensitive-data requests through a known independent channel.
  • SPF, DKIM, and DMARC help protect a domain from direct spoofing, but they do not prove that a message is safe.
  • A compromised mailbox can send mail that passes email authentication.

How whaling phishing works

Whaling uses information about an organization to make a fraudulent request appear routine. An attacker may use public staff pages, press releases, social posts, vendor names, or details exposed in an earlier email compromise. The message then poses as a chief executive, finance leader, legal contact, supplier, or another trusted authority.

The US Cybersecurity and Infrastructure Security Agency's guidance on business email compromise describes attacks that use social engineering to induce a payment or disclosure. In a whaling attempt, the authority of the impersonated person is part of the lure. The recipient may be told that a wire transfer, vendor-bank change, document release, or credential reset must happen immediately and without normal review.

The sender address deserves inspection, but it is only one signal. A lookalike domain can resemble a legitimate company domain. A reply-to address can direct responses elsewhere. A compromised real mailbox can contain correct signatures, prior conversation history, and internal vocabulary.

Email authentication addresses one part of this problem. RFC 9989 defines DMARC as a way for a domain owner to publish handling preferences for mail that fails DMARC validation. DMARC passes when SPF or DKIM passes with a domain aligned to the visible From domain. It can reduce successful direct spoofing of a protected domain, but it does not determine whether a request is authorized or whether a legitimate account has been compromised.

For broader controls around malicious email, use the Palisade email security learning hub.

When the answer changes

The right response depends on what the suspicious message asks you to do and how it was sent.

Treat the request as high risk when it asks for any of these actions:

  • A wire transfer, gift-card purchase, invoice payment, or vendor-bank detail change.
  • Credentials, multifactor authentication codes, tax records, payroll details, contracts, or customer data.
  • A new communication channel, especially one supplied by the message itself.
  • An exception to an approval, purchasing, or confidentiality process.
  • Immediate action combined with secrecy or pressure.
Use this decision rule: if the message would cause money, access, or sensitive information to leave the organization, confirm the request with the alleged sender through a contact method already known to the organization. Do not call a number, use a link, or reply to an address supplied in the suspicious email.
Do not process a changed bank account or high-value payment from an email instruction alone. Confirm it through the approved vendor contact and the organization's existing approval process.

A message that fails DMARC is useful evidence of potential spoofing when it uses your domain, but a passing result does not approve the transaction. The FBI's business email compromise guidance also recommends independently verifying payment-related requests and changes to payment instructions.

Decision flow for a suspected whaling request, from identifying a high-risk action to independent verification and authentication review
Source: Palisade.

A worked whaling verification example

A finance employee receives a message that appears to be from the CFO. It requests an urgent supplier payment and includes new bank details. The message may look plausible, but the request changes where money will go.

Use the evidence in this order:

Technical exampletext
Request: Urgent payment to a new bank account
Known risk: Payment instruction changed by email
Independent check: Call the CFO or supplier using a number in the approved directory
Authentication check: Inspect the visible From domain and message authentication results
Decision: Hold payment until the independent contact confirms the request

If the visible From address uses your organization's domain, inspect the delivered message headers. RFC 8601 defines the Authentication-Results header field, which can report results such as spf, dkim, and dmarc. Those results can help establish whether the message authenticated as expected, but they must be read alongside the exact From domain and the known-channel verification.

A simplified header pattern might look like this:

Technical exampletext
Authentication-Results: receiver.example;
  spf=pass smtp.mailfrom=yourdomain.com;
  dkim=pass header.d=yourdomain.com;
  dmarc=pass header.from=yourdomain.com

This pattern is not a safety verdict. It may be consistent with legitimate mail, but it can also appear when an attacker controls a legitimate account or an authorized sending path. The payment remains on hold until the independent confirmation is complete.

What to do after a suspected whaling message

First, preserve the message and report it through the organization's security process. Do not forward it externally with sensitive content exposed. Security staff may need the original message, its headers, the sender and reply-to addresses, URLs, attachment names, and the action requested.

Next, use the established communication channel to verify the request. For a supplier change, contact the supplier through the approved vendor record. For an executive request, call or message the executive through the company directory or another known channel.

Then review the applicable controls:

  • Require separate approval for high-value payments and vendor-bank changes.
  • Use phishing-resistant multifactor authentication where the organization supports it, particularly for executive, finance, administrator, and email accounts.
  • Review mailbox forwarding rules, delegated access, OAuth applications, and recent sign-in activity after suspected account compromise.
  • Train employees on the organization's exact verification process, not only on visual signs in suspicious messages.
  • Publish and maintain SPF, DKIM, and DMARC for domains that send mail. The guide to preventing phishing attacks covers the wider prevention program.
If you have a domain but no suspicious message header, a public record lookup can establish what it publishes today. It cannot prove the production sending path, a receiver's private decision, or whether future mail will authenticate.

Check the DMARC record that protects your domain

Inspect the domain's published DMARC record before assuming direct spoofing is blocked. Compare the public result with the sender domain in the suspicious message and with the authentication results from the delivered message.

Check the DMARC record

A public DMARC check cannot confirm that an executive approved a payment, identify a compromised mailbox, or explain why a specific receiver accepted a message.

Track the sending sources that still need remediation

If your domain sends mail through several business applications, a record check alone cannot show which legitimate sources fail alignment or whether a new sender later appears. Palisade is AI-first, agent-first DMARC software that analyzes DMARC aggregate-report data, identifies sending sources and authentication or alignment issues, and creates prioritized remediation tickets. It can propose the next DMARC policy step, while your team reviews the evidence and applies any DNS change.

Start with Palisade

Palisade does not authorize payments, change a DMARC policy without human action, or prove that every future message is legitimate.

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Samuel Chenard

Written by

Samuel Chenard

CEO & Co-Founder, Palisade

Samuel Chenard is the CEO and co-founder of Palisade, AI-first DMARC software for IT teams and MSPs, from one domain to thousands.

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