Spear Phishing Demystified: the Terms You Need to Know

  • 10 October 2019

Jargon is a hallmark of all industries. Cybersecurity is no different, but using the right security terminology has a real impact. When an organization’s data and systems are threatened by spear phishing attacks, being aware of evolving trends and the definitions of key terms could be the difference that helps prevent the next threat.

Spear phishing is the number one threat facing businesses today, but research still suggests that “lack of knowledge and awareness about cyber-attacks could hinder the growth of the spear phishing protection market.”

In this article we define and explain key spear phishing concepts and terms. (To learn more about how to prevent spear phishing attacks with machine-intelligent technology, read about Tessian Defender.)

Spear phishing definition, and other attack types

Although media outlets and security companies rightly pay a lot of attention to spear phishing, advanced impersonation spear phishing attacks come in many forms. Once you’ve read our breakdown of different key terms and what they mean, you’ll come away with a clearer understanding of the range of sophisticated inbound email threats.

Spear phishing

Spear phishing describes an advanced impersonation phishing attack directed at specific individuals or companies. (Head to the “Other useful terms” section below to see a definition of regular “bulk” phishing.) Similar to “bulk” phishing, spear phishing attacks are designed to trick people into taking an action like transferring funds or clicking on a malicious link. In contrast to bulk phishing, spear phishing attackers often gather and use personal information about their target to increase their probability of success. Because spear phishing emails are low-volume as well as more sophisticated in their construction and convincing in execution, they are far harder for traditional email security products to catch.

CEO fraud / executive fraud

CEO fraud is a type of spear phishing attack where attackers impersonate a CEO or another high-level executive. Here, attackers aim to trick the executive’s colleagues into carrying out actions that place data, money and/or credentials at risk. Attackers often use social engineering techniques (see “Other useful terms” below) to convey urgency and prevent targeted employees from thinking twice about following the instructions of the “CEO”. A notorious example of this kind of fraud saw an impersonation of Pathé France’s CEO lose Pathé €19.2m.


Whaling is related to CEO fraud, with a key difference: instead of impersonating senior executives and targeting lower-ranking employees, attackers target the big fish themselves (hence the term). A whaling attack might involve attackers trying to get the executive in question to divulge key credential information or other sensitive organizational data. This information can then be used to access confidential systems, or to make subsequent spear phishing attacks within the organization more authentic and effective. Because they are many times more likely to be targeted than rank-and-file employees, because they tend to be very busy, and because of their access and influence, senior executives can be especially profitable targets for attackers.

Forms of impersonation used in spear phishing attacks

Although all spear phishing attacks revolve around impersonation of some kind, impersonation itself can take many forms. Attackers impersonate people on email in order to:

• Steal money, data and credentials
• Compromise systems
• Take over accounts

Essentially, all spear phishing attacks use impersonation as a strategy. Mechanisms differ from the easy (display name impersonation) to the complex (direct spoofing). Here’s how we break impersonations down:

Business Email Compromise

According to the FBI, Business Email Compromise (BEC) attacks cost organizations $1.2bn in 2018 alone. BEC is closely related to spear phishing – and commonly confused with it – but is potentially still more damaging and severe. Attackers impersonate employees or external counterparties and send spear phishing emails to people within the organization being targeted, using social engineering techniques to convince targets to wire funds outside the organization or to click on dangerous links that risk compromising systems and/or data.

Readers should bear in mind that there are several different interpretations of BEC. For example, it’s often confused with Account Takeover (ATO): ATO describes the unauthorized takeover of someone’s actual account, using harvested credentials or “brute force” hacking.

Domain impersonation

These attacks involve attackers spoofing or impersonating an organization’s domain in order to appear legitimate. There are three main kinds of domain impersonation: root, top-level and subdomain. Below is an example of each of these impersonations, using the domain companyinc.com as a starting point:

Root: [email protected]-outbound.com OR [email protected]0mpanyinc.com
Top-level: [email protected]net
Subdomain: [email protected].secured-email.com

Display name impersonation

Display name impersonations involve attackers setting deceptive display names on their email accounts in order to mislead recipients. This might mean impersonating a senior executive within a company, or the name of a key supplier or partner. The technical skill required is effectively zero: most mainstream email clients offer users ways to change display names in their account settings. Display name impersonations are particularly effective when received on mobile devices, as the sender’s actual email address is usually hidden.

This image shows an example email from a CEO: there is no email address shown, meaning a busy employee has no immediate indication anything is amiss.

Attackers can also change a sender’s display name to include a genuine-seeming email address, such as “Thomas Edison <[email protected]>

You can see an example of this impersonation, which shows the faked display name (in bold) with the actual From: address next to it. Attackers bet that the target won’t realize the email address they see first isn’t actually the address from which the email was sent. This works especially well on mobile, where the From: address is unlikely to be visible.

Freemail impersonation

Freemail impersonation describes spear phishing attacks where criminals use the fake personal email address of a senior-level executive. An attacker impersonating the CEO of a company – let’s use Thomas Edison again – could send an email from [email protected] to an employee working in the finance department, for example, requesting an urgent transaction. Here’s the example from before:

Automatic “Out of office” replies are a useful tool for attackers planning freemail spear phishing campaigns. By probing lists of contacts, attackers can learn when a particular executive is out of the office. Details volunteered in OOO autoreplies may tell them how long the executive is out of the office for, and even where they’ve gone. With this knowledge, attackers are free to impersonate the executive’s personal email account (or simply register an authentic-looking freemail address) and target the executive’s colleagues with a convincing impersonation.

Other useful terms

Credential harvesting

Credential harvesting is often an end goal of spear phishing attacks. Attackers will use coercive emails to direct recipients to fake login pages or other websites, where credentials can be harvested. Attackers can monetize credentials by selling them, or by using stolen account information to make purchases. In an enterprise environment, compromised credentials can also place entire systems at risk, doing significant financial and reputational harm to the business. Having harvested credentials, attackers can even take over email accounts and begin targeting victims’ contacts.


Many spear phishing emails contain a payload: on email, this might be a malicious link or attachment that, when opened, triggers malware on affected devices or systems. Increasingly, spear phishing attacks don’t have a payload at all, relying on persuasive language to coerce an employee into making a mistake. In turn, this makes these attacks especially hard for traditional security tools to defend against.


Generally, phishing attacks are sent in bulk to a large audience, meaning the attackers’ language is relatively untargeted and unpersonalized. While phishing attacks can be successful, most attacks can be identified by traditional email security tools. This is why attackers have evolved to rely on spear phishing to extract money, data and credentials from organizations.


Ransomware attacks are growing in popularity and also need little or no technical skill to carry out. In a ransomware attack, an attacker holds an organization “hostage” by deploying malicious software across critical infrastructure. The attacker will threaten to steal money or data, or to cripple the organization’s systems unless a ransom is paid. Perhaps the most famous example of such an attack is the NotPetya worm which crashed systems around the world in 2017. Many ransomware attacks start with a spear phishing email containing a dangerous payload.

Social engineering

Social engineering describes the techniques attackers use to persuade people to take a dangerous action. Attackers may rely on the seniority of the person they are impersonating, or the illusion of urgency being created, to prompt a lower-ranking employee to take a desired action. Often, attackers will build trust with a target by communicating ‘normally’ for periods of time, using entirely innocuous language: this heightens the effect of coercive language when an attack is finally launched.


A spoof describes an impersonation where an attacker forges an email by modifying the email address from which the email appears to have been sent. (Many people don’t know that it’s possible for anyone with their own mail server to specify any From: address when sending an email, a loophole often leveraged by more sophisticated attackers.)

As an industry, cybersecurity is responding to a rapidly evolving threat landscape and growing more complex every day. It’s vital to understand the range of different concepts and terms that surround the exploding spear phishing crisis. A reminder: if you have further questions about spear phishing, speak to a Tessian expert.