How can I identify and remove email addresses submitted via list bombing?

Email marketer from Sendinblue suggests using honeypot fields on signup forms. These are hidden fields that bots often fill out, while legitimate users won't see them. Identifying submissions with data in these fields indicates a bot-generated signup.

Email marketer from Email Geeks recommends to check out cleantalk which will flag IPs on their network.

Email marketer from Reddit suggests analyzing signup patterns for anomalies. Look for spikes in signups from specific countries or IP ranges, or signups with unusual usernames or email addresses. This can help identify and remove bot-generated signups.

Email marketer from StackOverflow suggests implementing client-side JavaScript validation to catch obvious bot submissions before they reach the server. This can filter out signups with invalid email formats or other suspicious data.

Email marketer from Email Geeks shares that honeypot fields can also reduce bot submissions.

Email marketer from Reddit recommends implementing signup throttling to limit the number of signups from a single IP address within a specific timeframe. This can help prevent bots from flooding the system with fake accounts.

Email marketer from Email Marketing Forum recommends closely monitoring bounce rates after a signup. High bounce rates can indicate that many of the signups are invalid or fake, suggesting a list bombing attack.

Email marketer from Litmus explains that a good defense against list bombing is implementing a confirmed opt-in (COI) process, also known as double opt-in, which requires users to verify their email address before being added to the list. This helps ensure that only legitimate subscribers are added.

Email marketer from MailerQ shares that implementing reCAPTCHA on signup forms can effectively prevent bots from automatically submitting large numbers of email addresses. reCAPTCHA challenges users to prove they are human, blocking automated submissions.

Email marketer from Email Marketing Forum suggests regularly updating your blocklists with known spammers and bot IPs. This can help prevent them from signing up in the first place.

Expert from Email Geeks shares that they disallow signups from IPs on Spamhaus's XBL (but not PBL!) as it seems to be a good indicator of whether or not a signup IP is part of a botnet.

Expert from Email Geeks explains that your own subscription audit data is your best bet for removal after the fact.

Expert from Word to the Wise recommends implementing authentication and authorization methods, such as double opt-in, to reduce the number of fake signups making it onto your lists in the first place. Making sure the subscriber has actually consented to receiving messages from you is important for all kinds of deliverability reasons.

Expert from SpamResource explains that one method to identify list bombing is to watch for unusual signup patterns. This includes looking for high volumes of signups from similar IP ranges, using disposable email addresses, or providing nonsensical names.

Expert from Email Geeks shares that you can sometimes see patterns in the data itself related to list bombing, such as similar names using Hex Codes, addresses submitted directly to back-end APIs, or addresses added within specific time frames during the attack.

Expert from Email Geeks explains to look at all signups over the period of concern. Check if the same email signed up to multiple lists, if multiple signups came from the same IP, and look for anything distinctive in the user-agent or the data POSTed.

Expert from SpamResource shares that implementing CAPTCHA can prevent many automated bot submissions, but it's not foolproof. Advanced bots can sometimes bypass CAPTCHAs, so it's important to use other layers of protection as well.

Expert from Email Geeks shares that another tactic is a `phone` field that's hidden. Most (but not all) programmatic bombers won't recognize it as hidden and provide a submission. Then any record where that's got a value is suspect.

Documentation from OWASP explains that using techniques like CAPTCHA, rate limiting, and input validation are key measures for preventing automated attacks and list bombing on web forms.

Documentation from Google explains how to implement reCAPTCHA v3, which uses a risk score to identify suspicious behavior without requiring user interaction. This can help prevent bots from signing up without disrupting the user experience.

Documentation from Project Honey Pot explains that using their system and tracking can help to detect spammers and stop them from obtaining email addresses from your website, which can lead to list bombing.

Documentation from Cloudflare explains that using a bot management solution can help identify and mitigate automated attacks like list bombing. Bot management tools analyze traffic patterns to detect and block malicious bot activity.

Documentation from Stop Forum Spam shares that checking IP addresses against known spam databases can help identify malicious signups. If an IP address is associated with spam activity, the signup can be blocked.