(also email bomb attack, mail bomb)
Email bomb definition
A denial-of-service attack that involves sending large volumes of messages to an email address. Email bombing usually aims to render the victim’s email unusable or hide important messages (such as security breach alerts) in the torrent. The recipient of an email bomb may not be the attacker’s intended victim — criminals can also flood random mailboxes with junk to bring down the server hosting them.
Real types of email bomb attacks
- Mass mailing: Attackers send multiple copies of the same email to the same address. Mass mailing attacks usually employ botnets to rapidly overload the victim’s mailbox.
- List linking: Attackers subscribe the victim to multiple mailing lists, forcing them to unsubscribe manually. This attack is also known as an “email cluster bomb.”
- Zip bombing: Attackers attach compressed files containing large volumes of garbage to the message, overloading the mail service’s antivirus software when it tries to scan it.
Stopping email bombs
- Update your mail-delivery software to patch out any exploits and employ the latest algorithms against denial-of-service attacks.
- Limit permissions for distribution lists to internal authorized users only so you can prevent third parties from overloading mailboxes critical to your organization.
- Implement email filtering measures to stop spam from clogging mailboxes and hiding critical messages.
- Don’t publicly post email addresses in plain text because hackers use scraping software on websites to gather a list of potential targets for their attacks.