Email marketing is one of the most important tools digital marketers have today. After a recent spam attack, however, many marketers may find that their emails are now being blocked completely by Spamhaus.
The attack started about a month ago, but ramped up massively in the past couple weeks. Valid email addresses (primarily .gov addresses and government addresses from other countries) were added into many open email lists. These issue with this attack is from the primarily poorly managed lists that did not have a CAPTCHA in place, and didn’t have any type of confirmed opt-in, both of which are fairly standard today to help stop bots and spammers. Lists that did have standard protections in place minimized the impact to their users.
To make matters worse, if the owners of the email addresses being added to these lists didn’t click on the link in the emails they were sent, they would get a ‘reminder’ email. The reminder emails got sent out many times in some cases. This triggered Spamhaus to begin blocking the IP addresses for many email service providers (ESPs) to help cut back the spam. Of course, this also blocked the valid emails coming from these ESPs.
Spamhaus Chief Executive, Steve Lindford, Commented, “This incident involved a large number of government addresses belonging to various countries being subscribed to very large numbers of lists in a very short space of time by scripts run by the attacker(s). Most of the lists hit by the attack used COI and therefore only sent confirmation requests and did not subscribe any addresses.”
As with most spam attacks, however, even when the majority of the attacks are blocked by normal best practices, those that get through can cause significant problems.
When Spamhaus blocks IP addresses from delivering email addresses, many internet service providers also block those IP addresses to help cut down on the spam traffic and provide customers with a better experience.
At this point there doesn’t seem to be a full list of email service providers that were effected. In addition, many ESPs use multiple IP addresses so even those that were may not be completely unable to send out email blasts.
To check to see if your email domain, or the IP address that delivers your emails, has been blocked you can use a free tool from Spamhaus HERE. This issue has the potential to impact many marketers, and millions of emails, so make sure you take the time to check into this issue right away.
