Denial-of-Service Attack or List-Bomb Attack

What is it?

What is it?

A "Denial-of-Service (DoS) Attack" or "List-Bomb Attack" is a malicious attempt to disrupt the normal functioning of an email marketing campaign or system by overwhelming it with a large volume of fake or invalid email sign-ups. In a list-bomb attack, attackers flood an email list with numerous fake email addresses, often generated automatically using scripts or bots. This flood of fake sign-ups can strain email marketing infrastructure, impact deliverability rates, and degrade the quality of subscriber data.

Key points to remember

Key points to remember

  • Intent: A denial-of-service or list-bomb attack's primary intent is to disrupt email marketing operations, overwhelm systems, or sabotage campaigns.

  • Impact: List-bomb attacks can lead to inflated subscriber counts, increased bounce rates, decreased deliverability rates, and damage to the sender's reputation.


  • Prevention: Email marketers can mitigate the risk of list-bomb attacks by implementing CAPTCHA mechanisms, double opt-in confirmation processes, and email validation checks to verify the authenticity of new sign-ups.


  • Monitoring: Monitoring subscriber acquisition patterns and unusual spikes in sign-up activity can help detect and mitigate list-bomb attacks promptly.


  • Response: In the event of a list-bomb attack, email marketers should promptly clean their lists, remove fake or invalid sign-ups, and take steps to strengthen the security of their email marketing infrastructure.

Example of Use

Example of Use

  1. Spike in Sign-ups: An email marketer notices a sudden and unexplained surge in new subscriber sign-ups, far exceeding standard acquisition rates, indicating a potential list-bomb attack.


  2. High Bounce Rates: Following a suspected list-bomb attack, an email campaign experiences a significant increase in bounce rates due to the influx of fake email addresses added to the subscriber list.

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