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email virus

By Rahul Awati

What is an email virus?

An email virus consists of malicious code distributed in email messages to infect one or more devices. This malicious code can be activated in numerous ways: when the email recipient clicks on an infected link within the message, opens an infected attachment or interacts with the message in some other way.

Email viruses often spread by causing the malicious message to be sent to everyone in the original victim's address book.

Simply put, an email virus is a malicious code or a link to malicious code sent via email. The virus has the ability to replicate itself so it can quickly spread from one device to another. Thus, an email virus can not only infect the victim's computer, but it can also infect the computers of everyone in the victim's address book or those sharing the same network.

There are three primary ways an email virus can infect a victim's email and computer:

  1. via a phishing email
  2. included in an attachment
  3. embedded within the email body

Email viruses often look like executable files with extensions such as the following:

How to recognize an email virus

The various types of email viruses present themselves differently, so it's not always possible to recognize when an email message contains a virus.

Some infected emails have subject lines that don't make sense -- e.g., they contain gibberish text or strange special characters -- making them easy to spot. The other header fields and body content of the email may also look peculiar in some way. In other cases, the sender may be unknown to the user, which may raise the user's suspicion.

But other email messages containing viruses can be more difficult for recipients to identify. In such cases, the malicious actor may disguise the message so it appears to originate from a trusted and/or known sender. This is particularly true of email phishing campaigns carried out to further business email compromise attacks.

What can an email virus do?

An email virus can wreak all kinds of havoc:

Email viruses are especially dangerous since they can gather information about the victim -- and their contacts -- without their knowledge. Using such a covert means of attack, an email virus can end up causing massive damage in a short period of time. By the time the victims realize that there is a problem, it's often too late to contain the damage.

Email virus and phishing

Email viruses are often connected with phishing attacks, in which hackers send out malicious messages that look as if they are originated from legitimate, known or trusted sources, such as the following:

The attacker's goal is to trick the victim into revealing personal and potentially valuable information, such as their address, passwords, credit card number, Social Security number, etc.

Social engineering methods, like spam and malware-filled email messages, are commonly used by threat actors to infect user devices with email viruses and to attack their organization's network.

Types of email viruses

Email viruses can take many different forms:

Examples of well-known email viruses

This rogues' gallery of email viruses were particularly destructive:

How to detect email virus infections

Email viruses have evolved and become more dangerous over time. To combat them, detection methods have evolved as well:

How to prevent email virus infections

Email is an indispensable part of the modern worker's life. While it's not possible to stop using email to avoid email viruses, it is possible to take steps to avoid becoming a victim of such attacks.

The most important preventive tool is antivirus software. A trusted antivirus app that's updated with the latest virus definitions can go a long way toward thwarting email viruses.

Other ways to prevent an email virus from infecting a device or network include the following:

21 Sep 2021

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