Email, or e-mail, short for electronic mail, is a software system developed from a system that originated in the 1960s. Email is used for sending, storing, receiving, and forwarding text messages — and often attachments — on a packet-based computer network. Several terms for particular approaches to email have earned metaphoric nicknames. Two of these are email blast and email bomb Although these two terms similarly evoke an image of an explosion, they are actually rather different in meaning.
An email blast simply refers to a very large amount of email sent out at once. An email blast can either be spam or a completely legitimate activity, depending on circumstances. If the emailer is sending the email to users who have not opted-in to be on a mailing list, or otherwise violating the CANSPAM (Controlling the Assault of Non-Solicited Pornography And Marketing) Act of 2003, then the email blast will be considered spam. If the emailer is merely sending a very large number of emails to users whose addresses he or she has legitimately obtained and is, for example, offering a coupon or information about an upcoming sale, then the email blast may be perfectly legitimate. An email bomb, on the other hand — despite the similar name — does not have any legitimate use.
An email bomb is a type of denial-of-service (DOS) attack. A DOS attack is an attempt to destroy a person’s or organization’s access to a particular resource or service. It can be directed at overwhelming a network, cutting off communication between a user’s computer and its server, attempting to disrupt the overall service of the targeted person or organization, or trying to prevent a person or organization from accessing a particular service. An email bomb is an example of the final type, aimed specifically at impairing a person’s or organization’s email capability.
There are two overall types of email bombs. In the first type of email bomb, a person or organization is bombarded with an enormous number of emails sent to the relevant email address, overwhelming the system. In the second type of email bomb, called email subscription bombing, the target’s email is added to a large number of mailing lists, which are chosen because they send multiple messages on a daily basis. Email bombing can also affect those beyond the target, given sufficient traffic. If the source of the email bomb can be determined, a router can be configured to block the attack, and one should contact one’s Internet Service Provider (ISP) at the very least.