Email bombs are a common threat in today’s digital world. However, identifying and defending against them can be hard.
In this guide, we explore everything you need to know about email bombs and how to defuse them, including:
- What an email bomb is.
- How to identify and react to an email bomb attack.
- And most importantly, how to prevent future attacks!
What is an Email Bomb Attack?
An email bomb attack is a malicious cyberattack that inundates your inbox with a massive volume of emails in a short period. These email bomb attacks can:
- disrupt your communication by slowing down your system
- overload your inbox
- and even expose you to more harmful cyber threats.
Email bomb attacks can take various forms. But they always aim to overwhelm your email account. These attacks can target individuals, businesses, or institutions, leading to different levels of disruption and potential harm.
Looking for more tips on how to protect yourself from cyberattacks? Check out our 10 simple tips to protect your devices here.
What Does an Email Bomb Attack Look Like?
Before going over prevention methods, we must understand what an email bomb looks like.
Email bomb attacks are characterized by a sudden and overwhelming volume of emails. This can consist of hundreds or thousands of emails arriving in a span of seconds.
This type of attack is sometimes referred to as mass mailing. How can you spot the beginning of such an attack? Look out for the following characteristics:
- Lack of coherence: the content refers to websites or products of which you are not a subscriber or client (this might be a sign of list linking; more on that later).
- Duplicates of the same email with minor changes
- Unknown email senders: attackers frequently employ tactics to conceal their identity, using unfamiliar or spoofed sender email addresses.
For an organization, such an attack can severely disrupt the normal course of business. However, slowing down your inbox might not be the attacker’s only objective.
In practice, email bomb attacks can conceal a very real cybersecurity threat.
In some cases, the attack is a diversionary tactic. The flood of emails can overwhelm you and draw your attention away from other security concerns. For example, attackers may attempt to gain unauthorized access to your email account using various methods, such as phishing attacks or exploiting known vulnerabilities.
The intent here is to distract and confuse you while another attack is launched. If your credentials are already compromised, they may take this opportunity to gain access to your account. Or they may try to brute-force their way into your account.
Other forms of email bombs
Mass mailing is the most common type of email bomb attack. However, other forms of this attack also exist.
Zip bombing
Zip bombing is a strategy where the attacker sends a seemingly innocent-looking compressed file as an attachment.
However, this compressed file contains an exceptionally large amount of data. When decompressed, the file expands to an enormous size, sometimes reaching terabytes of data. This can overwhelm the recipient’s storage space and crash their email client. Due to high CPU and memory usage, the email server, client, or even the entire system may become unresponsive. In extreme cases, zip bombs can lead to data loss. This can happen as the storage space fills up and data is overwritten.
List linking
List linking, on the other hand, targets subscription-based services.
When a user subscribes to a newsletter, they receive a confirmation email. Attackers exploit this behavior by subscribing a victim’s email address to numerous mailing lists. This leads to an avalanche of confirmation emails flooding the victim’s inbox. Attackers often use automated scripts or bots to subscribe to multiple mailing lists simultaneously.
How to Respond to an Email Bomb Attack
If you are the victim of an email bomb attack, there are several immediate actions you should take.
Firstly, do not respond to an attacker.
Avoid engaging with the attacker to prevent escalation. Engaging with the attacker could increase email bombardment, worsening the situation. Refraining from clicking on links or opening attachments within suspicious emails is crucial to avoid potential malware infections.
Secondly, you should immediately notify your IT or cybersecurity team and contact your email provider.
Inform them of the situation and provide any available details about the attack. They are equipped to assist and can take measures to mitigate the attack, such as implementing additional security measures.
Finally, make sure sensitive accounts such as PayPal and Amazon have not been hacked. Email bombs are often used to obfuscate legitimate emails from these types of accounts warning you of withdrawal of funds.
If you still have access to your account, change any sensitive passwords. Ensure that the new password is strong and unique. You can check the strength of a password here. This step prevents further unauthorized access to your account. After taking the above steps, closely monitor your email account for any further suspicious activity. Keep an eye on incoming emails, especially those from unknown or suspicious senders. Report any additional malicious emails to your email provider promptly. Monitoring helps ensure that your account remains secure and that you stay informed about any ongoing threats or potential risks.
How to Prevent Future Attacks
Preventing email bomb attacks requires proactive security measures. These measures can be both technical and educational.
Implementing Security Measures
Enhancing your email security is crucial to defend against email bomb attacks. Here are five key measures to bolster your defenses:
- Strong Passwords: Create complex, unique passwords for your email accounts. Avoid using easily guessable information like birthdays or common phrases. Utilize a combination of uppercase and lowercase letters, numbers, and special characters. Regularly change your passwords, especially if you suspect any compromise.
- Two-Factor Authentication (2FA): Enable 2FA for an additional layer of security. With 2FA, even if an attacker gains access to your password, they won’t be able to log in without a secondary verification code, usually sent to your mobile device.
- Email Filtering and Spam Detection: Utilize email filtering and spam detection features provided by your email service provider. These tools can help identify and quarantine suspicious emails, reducing the chances of an email bomb attack reaching your inbox. If you’d like to learn more about how you can set up filters in Mailfence, you can check out our documentation here.
- Regular Software Updates: Keep your email client and security software up-to-date. Updates often include patches for known vulnerabilities that attackers could exploit. By staying current, you reduce your vulnerability to email-related threats. You can even bypass an email client entirely by using a web-based email provider.
User Education and Monitoring
Additionally, it’s important to educate yourself and others about email bomb attack threats. Recognizing the signs of such attacks, like a sudden influx of emails or unusual content patterns, is essential for timely response.
- Awareness. Many people have never heard of email bomb attacks. Raise awareness among colleagues by organizing a workshop and talking to friends and family.
- Vigilance and reporting. Encourage a culture of caution around suspicious email activity.
- Disguised email addresses. Get in the habit of hiding your email address online. Practically, you should never communicate your email address in clear text on public pages. If you really need to share your email address, use plus addresses (which you can create for free with Mailfence).
Last Words on Email Bomb Attacks
This wraps up our guide on email bomb attacks. We hope you found it useful and will be able to detect and react to mail bomb threats in the future.
Interested in stepping up your online security and privacy? Create a free Mailfence account today. And if you’re interested to learn more, check out our free email security & privacy course.
