E-mail bomb
Encyclopedia
In Internet
usage, an email bomb is a form of net abuse consisting of sending huge volumes of email
to an address in an attempt to overflow the mailbox or overwhelm the server
where the email address is hosted in a denial-of-service attack
.
and under the attacker's control. Similar to their use in spamming, the attacker instructs the botnet to send out millions or even billions 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 in purpose 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 just as 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.
is a variant of mail-bombing. After most commercial mail servers began checking mail with anti-virus software and filtering certain malicious file types, EXE
, RAR, Zip
, 7-Zip
. Mail server software was then configured to unpack archives and check their contents as well. A new idea to combat this solution was composing a "bomb" consisting of an enormous text file, containing, for example, only the letter z repeating millions of times. Such a file compresses into a relatively small archive, but its unpacking (especially by early versions of mail servers) would use a greater amount of processing, which could result in a DoS
(Denial of Service).
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
usage, an email bomb is a form of net abuse consisting of sending huge volumes of email
Email
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
to an address in an attempt to overflow the mailbox or overwhelm the server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
where the email address is hosted in a denial-of-service attack
Denial-of-service attack
A denial-of-service attack or distributed denial-of-service attack is an attempt to make a computer resource unavailable to its intended users...
.
Methods of email bombing
There are two methods of perpetrating an email bomb: mass mailing and list linking.Mass mailing
Mass mailing consists of sending numerous duplicate mails 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 "zombie" botnets; hierarchical networks of computers compromised by malwareMalware
Malware, short for malicious software, consists of programming that is designed to disrupt or deny operation, gather information that leads to loss of privacy or exploitation, or gain unauthorized access to system resources, or that otherwise exhibits abusive behavior...
and under the attacker's control. Similar to their use in spamming, the attacker instructs the botnet to send out millions or even billions 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 in purpose 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 just as 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.
List linking
List linking means signing a particular email address up to several email list subscriptions. The victim then has to unsubscribe from these unwanted services manually. 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. This method of prevention is easily circumvented: if the perpetrator registers a new email account and sets it to automatically forward all mail to the victim, he or she can reply to the confirmation emails, and the list linking can proceed.Zip bombing
A ZIP bombZip bomb
A zip bomb, also known as a Zip of Death or decompression bomb, is a malicious archive file designed to crash or render useless the program or system reading it...
is a variant of mail-bombing. After most commercial mail servers began checking mail with anti-virus software and filtering certain malicious file types, EXE
EXE
EXE is the common filename extension denoting an executable file in the DOS, OpenVMS, Microsoft Windows, Symbian, and OS/2 operating systems....
, RAR, Zip
ZIP (file format)
Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is...
, 7-Zip
7-Zip
7-Zip is an open source file archiver. 7-Zip operates with the 7z archive format, but can read and write several other archive formats. The program can be used from a command line interface, graphical user interface, or with Microsoft Windows shell integration. 7-Zip began in 1999 and is actively...
. Mail server software was then configured to unpack archives and check their contents as well. A new idea to combat this solution was composing a "bomb" consisting of an enormous text file, containing, for example, only the letter z repeating millions of times. Such a file compresses into a relatively small archive, but its unpacking (especially by early versions of mail servers) would use a greater amount of processing, which could result in a DoS
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
(Denial of Service).