Email bombing is a form of internet abuse in which massive volumes of identical emails are sent to a specific email address to affect the operating system of a computer. When the mailbox gets flooded with countless unwanted emails, its capacity gets exhausted, leading to an inability to receive further emails. This may be done to prevent the victim from receiving or noticing some other important message in their mail. A sluggish system or inability to send or receive emails can be indications of getting email bombed. This happens because the system is already pre-occupied with processing countless emails.
Email Bombing and Spamming
There are three methods of email bombing: Mass mailing, List linking and ZIP bombing. Mass mailing involves sending several duplicate emails to the same address but can be easily detected by spam filters. The second, List linking, involves subscribing the target email address to different email list subscriptions. The user would always receive spam mail from all these subscriptions and will have to manually unsubscribe from each list separately. Email bombing done using ZIP archived attachments containing millions and billions of characters is known as ZIP bombing. Mail servers checking the mail with anti-virus software would require a greater amount of processing power, possibly resulting in Denial of Service.
While you cannot eliminate the chances of being email bombed, there are some preventive & protective measures you can take to reduce their effect. Here are some of them:
1] Use anti-virus software and firewall – You can reduce the chances of being attacked, by using anti-virus and putting up a firewall configured to restrict traffic.
Use email filter applications– Email filters are packages that are used to manage unsolicited emails by filtering emails according to the source address. Some of the email filters that are commonly used for Mac OS are:
- Personal AntiSpam X5
Filter package tools for Windows include:
- Email Chomper
- Spam Buster
- Cactus Spam Filter
2] Use Proxy Servers– It is difficult to spam and filter each and every email bomb coming from different IP addresses. Such a situation could be mitigated with the help of proxy servers. A proxy server is a computer to which all other computers in a particular network are connected. The proxy server has certain rules for filtering the messages it receives requesting for information and resources of the computers connected to it. This helps in filtering malicious requests and messages from suspicious IP addresses before they are sent to the clients of the proxy server.
3] Using Simple Mail Transfer Protocol (SMTP)- Denial of Service attacks can also be solved using SMTP which is a method of authenticating the exchange of messages across Internet protocols. The clients access their mailbox using Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP). Through SMTP, the Mail Submission Agent then transfers a mail or information to the Mail Transfer Agent (MTA). On connecting to the SMTP, the MTA analyses the mail exchange record and IP address of the sender and reject the message if they are found suspicious. Security mechanisms such as authentication and negotiation are processed during the exchange of data.
It is important that you identify the source of the email bombs and once you have identified it, you need to configure your router or firewall and prevent incoming packets from that address.
Read next: Benefits of Masking Email Address.