List poisoning

The term list poisoning refers to poisoning an e-mail mailing list with invalid e-mail addresses.

Once a mailing list has been poisoned with a number of invalid e-mail addresses, the resources required to send a message to this list has increased, even though the number of valid recipients has not. If one can poison a spammer's mailing list, one can force the spammer to exhaust more resources to send e-mail, in theory costing the spammer money and time.^[1]

Poisoning spammers' mailing lists is usually done by blacklists submitting fake information to email submit style offers, or by posting invalid email addresses in a Usenet forum or on a web page where spammers are believed to harvest email addresses for their mailing lists.

• Syntactically invalid email addresses used to poison a mailing list could be easily filtered out by the spammers, while using email addresses that are syntactically correct could cause problems for the mail server responsible for the email address.^[1]
• Implementations of spam poisoning systems can be avoided, if spammers learn of their location (e. g., they could automatically filter out any address containing "spampoison.com").
• Spammers often steal resources so that the efficiency of a mailing places little financial burden on the spammer.

• Anti-spam techniques (e-mail)
• Address munging
• Botnet
• E-mail address harvesting
• Spamtrap
• Stopping e-mail abuse

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• List poisoning code written in Perl.
• List poisoning code written in PHP.
• Simple list poisoning code written in BASH shell script and a working example.
• Hosted list poisoning and honeytrap SpamPoison