Email address disclosure

Febna V M
Published on
06 Dec 2023
6 min read

Email address disclosure refers to the unintentional or unauthorized exposure of email addresses to individuals or entities that were not meant to have access to them.

It occurs when email addresses are shared, published, or made visible to others without the explicit consent of the email account owners.

How is email address disclosure exploited?

An e-mail address is used to identify an e-mail box. Some servers disclose the email addresses registered within the application. The attacker can attempt to exploit this vulnerability through:

1. Spam email

Spam e-mail (junk mail) that includes mail from phishing websites and sites with malware. The malware in these e-mails might be through script links or any other executable links.

It can also be a part of any attachments with the mail.

2. Brute force attacks

Brute-force attack is a trial-and-error attack to obtain PIN numbers and passwords of users.

Brute force attacks are executed using brute force attack software. This software generates many sets of random numbers and matches the number with the pin.

This process continues until the password gets a match.

3. Phishing

Phishing is a fraudulent method to obtain sensitive information from the users.

The attacker phishes data by spamming users. The collected data through phishing is sold off in the dark web.

4. Unauthorized access attempts

Unauthorized access is an attacker getting access to a user’s account.

What are the impacts of email address disclosure?

The disclosure of email addresses can have several significant impacts, both on individuals whose email addresses are exposed, and on the organizations or entities responsible for the breach.

Here are some of the key impacts:

1. Privacy violation

Email addresses are considered personal and sensitive information. When disclosed without consent, it represents a violation of individuals’ privacy rights.

Users may feel their privacy has been compromised, leading to mistrust in the entity responsible for the disclosure.

2. Increased spam and phishing attacks

Exposed email addresses become attractive targets for spammers and cybercriminals.

Users may experience a surge in unsolicited emails, spam, and phishing attempts, potentially leading to a cluttered inbox and increased risks of falling victim to phishing scams.

3. Identity theft and fraud

Email addresses, when combined with other personal information, can be used in identifying theft and fraudulent activities.

Cybercriminals can use the disclosed email addresses as part of social engineering attacks to gather more information about the individuals or attempt to gain unauthorized access to their accounts.

4. Reputational damage

Organizations responsible for email address disclosure may suffer from reputational damage.

Users and customers may lose trust in the organization’s ability to protect their personal information, leading to a negative impact on the organization’s brand image.

In some jurisdictions, the unauthorized disclosure of personal information, including email addresses, may be a breach of data protection laws.

Organizations found to be in violation of such laws could face legal consequences, including fines and penalties.

6. Business impact

For businesses that rely on email marketing or communication with their customers, the disclosure of email addresses can lead to a decline in customer engagement and trust.

Users may unsubscribe from mailing lists or avoid interacting with the organization’s communications due to concerns about their privacy.

7. Loss of confidentiality

If the email addresses belong to individuals in sensitive positions or organizations dealing with confidential information, their exposure could compromise the confidentiality of communications and sensitive data.

To mitigate the impacts of email address disclosure, organizations must take measures to protect user data, implement robust security practices, and comply with data protection regulations.

How can you prevent email address disclosure?

For individuals, it is essential to be cautious about sharing personal information online and to use strong security practices, such as enabling two-factor authentication and using unique and strong passwords for email accounts.

Here are some tips for preventing email address disclosure:

1. Use generic email addresses

Instead of using specific email addresses, use generic email addresses such as contact@, info@, or support@.

This will make it more difficult for spammers to harvest email addresses from your website.

2. Only disclose email addresses when necessary

Only disclose email addresses when it is absolutely necessary, such as when users need to contact you for support.

If you do not need to disclose email addresses, do not do so.

3. Use a CAPTCHA

A CAPTCHA can help to prevent automated bots from harvesting email addresses from your website.

4. Encrypt email addresses

You can encrypt email addresses before they are transmitted over the network. This will make it more difficult for spammers to harvest email addresses.

5. Use a web application firewall (WAF)

A WAF can help to filter out malicious traffic that could be used to exploit vulnerabilities in your website.

6. Sanitize all user input

Before storing user input in a database, you should sanitize it to remove any potential malicious code. This will help to prevent spammers from using your website to send spam.

7. Keep your website software up to date

You should regularly update your website software with the latest security patches. This will help to protect your website from known vulnerabilities.

8. Use a honeypot email address

A honeypot email address is a fake email address that is designed to attract spam. When a spammer sends an email to a honeypot email address, the email will be intercepted and not delivered to the intended recipient.

9. Educate your users

You should educate your users about the risks of email address disclosure and how to protect themselves.

In short, use a structured mechanism. These mechanisms can automatically enforce the separation between data and command and validate the values for commands and their relevant arguments.

By following these tips, you can help to reduce the risk of email address disclosure and protect your users from spam and other malicious activity.

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Written by
Febna V M
Febna V M
Cyber Security Engineer
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