Email bomb

Malicious email abuse

denial of service attacks

On Internet usage, an email bomb is a form of net abuse that sends large volumes of email to an address to overflow the mailbox, overwhelm the server where the email address is hosted in a denial of service attack (DoS attack) or as a smoke screen to distract the attention from important email messages indicating a security breach.

There are three methods of perpetrating an email bomb: mass mailing, list linking and zip bombing.

Mass mailing consists of sending numerous duplicate emails to the same email address. These types of mail bombs are simple to design but their extreme simplicity means they can be easily detected by spam filters. Email bombing using mass mailing is also commonly performed as a DDoS attack by employing the use of "zombies" botnets; hierarchical networks of computers compromised by malware and under the attacker's control. Similar to their use in spamming, the attacker instructs the botnet to send out millions of emails, but unlike normal botnet spamming, the emails are all addressed to only one or a few addresses the attacker wishes to flood. This form of email bombing is similar to other DDoS flooding attacks. As the targets are frequently the dedicated hosts handling website and email accounts of a business, this type of attack can be devastating to both services of the host. This type of attack is more difficult to defend against than a simple mass mailing bomb because of the multiple source addresses and the possibility of each zombie computer sending a different message or employing stealth techniques to defeat spam filters. The victim then has to unsubscribe from these unwanted services manually. The attack can be carried out automatically with simple scripts: this is easy, almost impossible to trace back to the perpetrator, and potentially very destructive. A massive attack of this kind targeting gov email addresses was observed in August 2016. In order to prevent this type of bombing, most email subscription services send a confirmation email to a person's inbox when that email is used to register for a subscription.

A "text bomb" is a similar variant of sending a large number of text messages over SMS. The technique is a means of cyberbullying or online harassment. Apps online on the Android operating system have since been banned as a means of sending text bombs. The text messages may also lead to high phone bill charges on some mobile plans. Additionally, certain phone apps have also been created to prevent text bombs on Android OS.