Whaling Attacks: How Cybercriminals Target Your C-Suite

Whaling vs. Phishing vs. Spear Phishing: Key Differences

WatchGuard Technologies Chief Security Officer Corey Nachreiner explains that traditional phishing is akin to casting a net far and wide in the hope of catching something.

“Cybercriminals are ready to pounce on a victim who is curious enough to click through,” he says.

Spear phishing is much more targeted, intended to catch a specific set of victims, with attacks crafted at some level of effort in the hope of standing out and catching the user off guard by using a relevant call to action that would seem plausible.

Whaling is a targeted attack like spear phishing, in that effort is used to craft an attack that’s relevant and time-critical but the range of victims is deliberately limited; typically, to one person at a time.

Whaling is usually reserved for high-end executives, including C-suite personnel who, given their position within a target organization, could provide a level of access to information that would be detrimental if lost.

“Phishing of all kinds and social engineering remain key methods cybercriminals use to infiltrate their victim's organization,” Nachreiner adds.

LEARN MORE: How to counter the most common cybersecurity threats.

How Cybercriminals Research and Target C-Suite Executives

Typically, adversaries who are preparing whaling attacks will begin with open-source intelligence, reviewing executive bios, LinkedIn profiles, press releases and social media to understand a C-suite leader’s role, responsibilities and recent business activity.

“That research allows them to craft highly credible, context-aware lures that are tailored to the executive’s real-world priorities,” says Cristian Rodriguez, field CTO for the Americas at CrowdStrike.

Increasingly, AI tools are accelerating the profiling, reconnaissance and personalization that enable adversaries to generate convincing executive impersonation at greater speed — impersonation that is nearly impossible to detect without proper training.

Real Whaling Attack Examples: Lessons From Major Breaches

In 2015, attackers impersonated Mattel’s newly appointed CEO in an email sent to a senior finance executive, requesting approval for a $3 million payment to a bank account in China. The message was sent shortly after the leadership change, when internal processes were in flux, and closely matched Mattel’s normal approval workflows and regional business activity.

“No malware or technical exploitation was used,” Nachreiner says. “The fraud relied entirely on timing, internal process knowledge and executive impersonation, and the payment was authorized as a result.”

More recently, Hong Kong police disclosed a $25 million fraud in which attackers used AI-generated video and audio deepfakes to impersonate a company’s UK-based chief financial officer and other colleagues during a live video call.

Nachreiner explains that while a finance employee initially questioned an email requesting a confidential transfer, he was convinced after joining the call, where multiple familiar executives appeared on screen and verbally confirmed the request.

All participants except the victim were real-time deepfakes created from publicly available video and audio. The employee subsequently authorized several transfers totaling approximately $25 million.

Technical Defenses: Email Security Tools That Stop Whaling

Aaron Bugal, a field CISO at Sophos, says tooling that allows for feedback directly from the user into both an autonomous and human-based information loop can help both the organization and its users understand and effectively deal with new and emerging attacks.

“Even better is when examples from the detected attacks can be used to generate a template for your own security awareness training and learning management system,” he says.

He advocates for tooling that can warn users if a message looks or sounds like a phish and help them report it directly to their own security operations team or managed security service.

“If your email security tooling doesn’t have these capabilities today and is unlikely to do so, then it may be time to review that,” Bugal adds.

He cautions that relying on simplistic AI models to detect spam and potential phishing emails — or not allowing users to provide feedback to what they see delivered to their inbox — is a blind spot that will become a problem.

DIVE DEEPER: The differences between phishing and other cyberattack methods.

Executive Security Training: Beyond Generic Phishing Awareness

Bugal says that including real world examples that are relevant from your own organization immediately helps highlight that every organization is a potential victim.

Executive accountability for healthy operation of the organization should also encompass the cyber resilience capabilities of the business, he adds.

“They have to play their part in understanding where risk manifests and how to best manage it,” he says. “Executive security awareness training should not be optional at this level. It needs to be mandatory.”

Nachreiner says executive training must go beyond email, noting modern whaling campaigns increasingly use text messaging, voice calls, collaboration tools, and video meetings.

“Executives should be trained to expect impersonation across all channels, including AI-generated voice and video deepfakes,” he says.

From Nachreiner’s perspective, the lesson is no longer simply “do not click suspicious links.”

“Do not trust a single communication channel, especially when authority or urgency is involved,” he says.