As we approach the end of summer, Mailprotector Security Center reports that spam rates remain high. During the last four weeks, the spam rate for all email traffic flowing through the Mailprotector security system reached one of the highest levels at 96.1%. The report also notes that the preferred method of attack from spammers is the Dictionary Harvest Attack – DHA.
Also known as a “Directory Harvest Attack”, the DHA is becoming a much more frequent occurrence. The most important commodity for a spammer is a valid email address. As users become more cautious about the disclosure of their email address, valid addresses are becoming harder to come by.
In a typical DHA the spammer will use a “dictionary” of hundreds of thousands of common names and name combinations to continually query a non-secure email server. The spammer will not attempt to send a message, but simply ask the receiving server if it will accept a message for the particular address. The spammer then waits to see if an error message is returned. If one is not, then the spammer now has a valid email address that can be used and sold to other spammers.
As part of our exchange spam filtering service, Mailprotector provides comprehensive security from DHA and other SMTP-based server attacks. Head over to http://www.mailprotector.net to learn more about this and other services that Mailprotector offers.
Related posts:
