Email Hijacking Definition

KZero Staff
Jul 27, 2023

What is Email Hijacking?

Email hijacking is a cyberattack in which a cybercriminal gains access to a user’s email account. This can be accomplished in a variety of different ways — such as phishing or password guessing — and enables the attacker to use the compromised account for other attacks.

How Does Email Hijacking Work?

An email hijacking attack requires the attacker to take over a user’s email account. This typically involves the theft of user credentials, which can be accomplished via various means, including:

  • Phishing: A phishing email could trick the user into entering login credentials into a fake, attacker-controlled site.
  • Malware: Keylogging malware can record a user’s password as they type it, or malware could steal passwords stored on a computer.
  • Password Guessing: If a user has a weak password or if it was exposed in a data breach, an attacker may be able to guess the password for their email account.

The Impacts of Email Hijacking

A successful email hijacking attack enables a cybercriminal to perform a wide variety of malicious actions. Some of the ways that an attacker could use a compromised email account include:

  • Data Breach: Email accounts can contain a large volume of sensitive or confidential information. With access to these accounts — and the cloud services associated with them — an attacker may be able to steal a large amount of sensitive data from a company or individual.
  • Account Takeover: Email accounts are commonly used to establish a user’s identity during password resets. An attacker with access to an email account can access any online account linked to that email account.
  • Phishing: A compromised email account can be used to carry out spear phishing attacks. These attacks will appear much more believable because they can come from a legitimate account and may even involve replies to existing conversations.

A successful email hijacking attack doesn’t only affect the owner of the email account. It also impacts anyone who might receive and trust an email from that compromised account, both inside and outside the organization.

Protecting Against Email Hijacking

Email hijacking attacks involve the attacker gaining access to an email account. Typically, this involves compromising the user’s credentials via phishing, password guessing, or similar means.

The best way to protect against email hijacking is to implement strong authentication. Users should enable multi-factor authentication (MFA) where available to make it more difficult for a cybercriminal to gain access to their accounts. Organizations can help by enforcing the use of MFA where possible or supporting the use of alternative authentication mechanisms — such as biometrics or passwordless authentication — where available.

A company can also take steps to prevent or mitigate email hijacking attacks. For example, a company could monitor for and block suspicious login attempts and implement lockouts after a certain number of failed logins for corporate emails. Additionally, the use of email scanning and endpoint security solutions can reduce the risk of phishing or infected emails.


Email hijacking is a serious threat because it involves an attacker taking control of a user’s email account, which is commonly used as proof of a person’s online identity. Email hijacking can be used to steal data, compromise other accounts, or perform phishing attacks. The best defense against email hijacking is to implement strong authentication, such as MFA or passwordless.

KZero Staff

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