List bombing

List bombing is a malicious tactic used by attackers to populate email databases with fake addresses or, worse, real addresses without the consent of their owners.

Imagine this: a subscription form on your website receives hundreds or thousands of email entries in a short period of time.

It might seem like great news – your list is growing!

But when you check those emails, you realize that most of them are fake, or even worse, they belong to people who have never heard of you.

In other words, they are bombarding your list with spam.

This attack is usually carried out through automated scripts that exploit online registration forms, sending multiple subscription requests in a short time.

Compounding the problem is that many times the emails used belong to real people who have not given their consent.

As a result, those people start receiving your emails, leading to complaints, an increase in spam reports and, potentially, your domain or email server being blocked.

How does list bombing affect email marketing?

List bombing can have serious repercussions on your email marketing campaigns:

· Damage to the sender’s reputation

When you send emails to people who have not subscribed, it is very likely that these emails will end up being flagged as spam.

The more spam reports you receive, the more you will damage your sender reputation.

This, in the long run, will affect the deliverability of your campaigns.

Email service providers, such as Gmail or Outlook, may start sending your emails directly to the spam folder.

· Additional costs

Many email marketing service providers charge based on the size of your subscriber list or the number of emails you send.

If your list is bloated with bogus or unwanted emails, you will be paying more money for nothing.

In addition, cleaning these lists can cost extra if you need to pay for specialized services.

· Loss of trust

Imagine that a person receives an email from your brand without having subscribed.

They will probably not only flag it as spam, but also develop a negative perception of your company.

In the long run, this can affect your brand image and reduce conversion rates in future campaigns.

· Legal issues

Depending on the jurisdiction in which you operate, sending emails to people who have not given their consent may violate data protection laws, such as GDPR in Europe or CAN-SPAM in the United States.

This can result in substantial fines and other legal penalties.

How does list bombing strategies are applied?

List bombing is usually done through bots or automated scripts that detect vulnerable subscription forms.

These scripts send a flood of emails to the form, often using lists of email addresses obtained from stolen or randomly generated databases.

Attackers usually don’t have a personal target against your company, but rather seek to create chaos and damage your reputation or server resources.

In other cases, attackers may use List Bombing as a form of DDoS (Denial of Service) attack, where the goal is to overload your server with so many registration requests that it collapses.

In addition, this can create a domino effect: if people who receive your unsolicited emails complain about spam, your email service provider can suspend your account.

How to protect yourself from List Bombing

Fortunately, there are several steps you can take to protect yourself from this threat. Here are some key recommendations:

· Implement CAPTCHAs on registration forms

CAPTCHAs, those little challenges that ask you to identify images or type characters, are an excellent defense against bots.

By implementing this measure on your signup forms, you make it harder for automated scripts to send out bulk requests.

· Double Opt-in

This is one of the best practices in email marketing and helps not only to avoid list bombing, but also to ensure that your subscribers actually want to receive your emails.

When you use a double opt-in form, people must confirm their subscription through a verification email before they are added to your list.

· Constant analysis

If you notice a sudden increase in the number of subscribers, it’s a red flag.

Continually review your subscription forms and, if possible, limit the number of subscriptions from the same IP address in a short period of time.

· Email address validation

Using tools that validate email addresses before adding them to your list can be useful for filtering out bogus or invalid emails.

There are many platforms that can perform this task automatically.

· Server and form protection

Make sure the forms on your website are well protected and up to date.

Some attackers exploit vulnerabilities in the code of the forms to run List Bombing attacks.

What to do if you have already been a victim of List Bombing?

If you have already been the victim of a List Bombing attack, the first thing to do is to clean up your subscriber list.

In this way, you will reduce the amount of emails you send and minimize the risk of spam reports.

In addition, it is important to notify your email service provider about what happened.

They can help you take additional measures to prevent this type of attack from happening again in the future.

And finally, if your emails have been reported as spam, it is essential that you work to restore your reputation.

This may take time, but with the right email marketing practices, it is possible to restore trust in your domain.

Conclusion

List bombing is a serious problem that can seriously affect your email marketing campaigns.

Although it is not always 100% preventable, implementing measures such as CAPTCHA, double opt-in and regular monitoring of your forms will help minimize the risk.

In the long run, protecting your subscriber list will not only save you money, but will also improve the effectiveness of your campaigns and keep your reputation intact.