What are the objectives and mitigation strategies for IP list bombing on email sign-ups?

Email marketer from Email Geeks responds that stacking several remedies can lead to a near-perfect solution, with network layer protection solving 95% of the problem and other methods contributing a small percentage. However, they add friction for the end-user, which should be considered.

Email marketer from Formspree explains that you can implement a honeypot field in your forms. These are fields that are hidden from regular users, but are often filled in by bots. If these fields are filled out then the form submission can be automatically rejected.

Email marketer from Email Geeks shares that in generic cases, you can solve 95% of the list bombing problem with network layer protection and that services like CloudFlare can block/challenge bad actors at the networking level, before they even request the page.

Email marketer from SaneBox responds that motivations behind subscription bombing extend beyond mere harassment, including attempts to mask fraudulent transactions or obscure security alerts. The sheer volume of emails makes it difficult for the victim to notice crucial notifications.

Email marketer from Sucuri shares that a Web Application Firewall can filter malicious traffic, including that used in subscription bombing attempts, before it reaches the server, effectively mitigating the attack at an earlier stage.

Email marketer from MailerCheck shares that monitoring signup patterns is essential. A sudden, unusual surge in subscriptions, particularly from similar IP addresses or domains, should trigger an investigation and potential implementation of stricter verification measures.

Email marketer from Cloudflare explains that subscription bombs overwhelm email inboxes with unwanted subscriptions, aiming to either harass the recipient, obscure important emails (like bank alerts), or potentially leverage the overwhelmed address for further malicious activities. They also can be used to undermine marketing efforts.

Email marketer from StackExchange explains that rate limiting signup requests from the same IP address can significantly reduce the impact of list bombing. Additionally, using a challenge-response system (like CAPTCHA) and closely monitoring subscription sources can help identify and block malicious actors.

Email marketer from ZeroBounce shares that mitigation strategies include implementing double opt-in, using CAPTCHA, monitoring for suspicious activity (like sudden spikes in subscriptions), and using email verification services to detect and remove invalid or suspicious email addresses.

Email marketer from Email Geeks shares that one reason for adding addresses to a list is for bad actors to take your content and rebroadcast it with spam to their own list to trade off your content reputation.

Email marketer from Reddit shares that the objective of list bombing isn't always immediately obvious, but it can range from burying important emails (like password reset requests) to simply overwhelming the recipient as a form of harassment. It can also be a distraction technique while other attacks take place.

Expert from Email Geeks explains that subscription bombing is typically used in two contexts: harassment of the target victim by adding them to numerous lists, and facilitating crime by overwhelming the victim's mailbox to hide important messages.

Expert from Email Geeks explains that another scenario is corporate sabotage by a competitor or a dissatisfied customer, where the goal is to mess up the list and tank the sender's reputation. Also, hackers may look for exploits by testing email addresses and seeing if they can find vulnerabilities.

Expert from Spam Resource explains that blocking IPs is generally ineffective against determined spammers because they use a large number of IPs or compromised machines, making it a 'whack-a-mole' game. Trying to block IPs is not a good mitigation strategy.

Expert from Email Geeks responds that there's no single solution to fix list bombing, but there are mitigation strategies. They say this as someone who’s been actively involved in the mitigation and a victim.

Expert from Word to the Wise explains that list bombing and other forms of spam sign-ups can be mitigated using techniques such as confirmed opt-in, rate limiting, CAPTCHAs, and the use of honeypots in order to protect your website and users.

Documentation from RFC Editor defines the purpose of opportunistic TLS which to to provide privacy against passive eavesdropping. This provides no protection against active attacks. The threat model is a client communicating to server where there is no prior arrangement for security.

Documentation from Microsoft support explains that users should add safe senders to their blocked senders list. This provides a way to reduce future spam in a similar theme. Microsoft also explains that they work to filter out spam before it reaches your inbox.

Documentation from OWASP details the use of rate limiting, CAPTCHAs, and bot detection techniques to prevent automated attacks, including subscription bombing. They highlight the importance of adapting these techniques as attackers evolve their methods.

Documentation from Google Support explains that marking unwanted emails as spam helps improve filtering accuracy for the user and others, training the system to better identify and block similar messages in the future. Reporting spam helps Google identify and stop malicious attacks.