The GTUBE is a 68-byte test string used to test anti-spam

E-mail spam

Email spam, also known as junk email or unsolicited bulk email , is a subset of spam that involves nearly identical messages sent to numerous recipients by email. Definitions of spam usually include the aspects that email is unsolicited and sent in bulk. One subset of UBE is UCE...

 systems, in particular those based on SpamAssassin

SpamAssassin

SpamAssassin is a computer program released under the Apache License 2.0 used for e-mail spam filtering based on content-matching rules. It is now part of the Apache Foundation....

. In SpamAssassin, it carries an antispam score of 1000 by default, which would be sufficient to trigger any installation.

Contents

The contents of the string are as follows:

XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X

and should be placed in the message body of an RFC 5322 compliant 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...

 message, without any linebreaks or whitespaces.

There exist some varieties, notably the NAItube (which will carry a variable weight) and the GTphish (which will trigger specifically as a phishing

Phishing

Phishing is a way of attempting to acquire information such as usernames, passwords, and credit card details by masquerading as a trustworthy entity in an electronic communication. Communications purporting to be from popular social web sites, auction sites, online payment processors or IT...

 mail), which are used in the McAfee

McAfee

McAfee, Inc. is a computer security company headquartered in Santa Clara, California, USA. It markets software and services to home users, businesses and the public sector. On August 19, 2010, electronics company Intel agreed to purchase McAfee for $7.68 billion...

 implementation of SpamAssassin

SpamAssassin

SpamAssassin is a computer program released under the Apache License 2.0 used for e-mail spam filtering based on content-matching rules. It is now part of the Apache Foundation....

.