What sort of email scam is "Insufficient Email Capacity"

What is "Insufficient Email Capacity" scam?

We have examined the email and concluded that it is a scam. The message is designed to appear as an automated storage warning from an email service provider. The scammers behind it seek to trick unsuspecting recipients into entering their email login credentials on a fraudulent website. This scam email should be ignored to avoid having the targeted account compromised.

"Insufficient Email Capacity" email scam overview

The "Insufficient Email Capacity" email claims that the recipient's mailbox has exceeded 90 percent of its storage quota. It lists specific figures, such as a quota of 524288000 bytes and current usage of 474562205 bytes (90.52%), to make the alert look like a genuine automated system message.

It warns that if the mailbox runs out of space, incoming and outgoing mail may be restricted. To "fix" this, the email includes a button asking recipients to update their account. A date and time stamp is added near the bottom, creating a false sense of urgency meant to push recipients into acting quickly without thinking it through.

Clicking the button opens a fake phishing page styled to look like a Gmail sign-in screen, placed over what appears to be Google's own promotional page for Gmail. The recipient's email address is already filled in, and the page asks only for the password before pressing a "LOGIN" button.

Whatever password is typed into this form is sent directly to the scammers, not to Google. Notably, the fake login page is hosted on quanticasrl.com, a site that appears to have nothing to do with Google or any email provider. This points to the website having been compromised and quietly abused to host phishing pages.

Gaining access to someone's email account lets criminals reset passwords on linked services, read private messages, send scam emails to the victim's contacts, and dig through old messages for banking details, personal documents, or other sensitive data. Google and other legitimate email providers have no connection to this scam.

Conclusion

In conclusion, this email is a phishing scam disguised as an automated mailbox storage warning. It aims to steal email account login credentials through a fraudulent Gmail-style login page. Recipients should ignore the email and avoid entering any information on the linked site to protect themselves from account takeover and identity theft.

Sometimes, scams like this are used to deliver malware.

More examples of similar scam emails are Mailbox Quarantine Alert, Account Not Validated, and SWIFT Confirmation Copy.

How do spam campaigns infect computers?

Cybercriminals often distribute malware through email by attaching infected files. These can be executable programs, Microsoft Office documents containing malicious macros, PDF files, archive files such as ZIP or RAR, or script files disguised as something harmless. Opening or running these files can trigger an infection.

Emails may also contain links to compromised or malicious websites instead of attachments. Visiting such a link can prompt an automatic download or trick the visitor into manually downloading and running a harmful file. In most cases, malware cannot install itself without some action taken by the user.

How to avoid installation of malware?

Treat unexpected emails about account problems, storage limits, or security alerts with suspicion, especially if they push for immediate action. Avoid clicking links or downloading attachments from messages you were not expecting, even if they appear to come from a familiar company.

Always download software and updates from official websites or app stores, and stay away from pirated programs, cracks, and key generators, since these are frequently used to spread malware. Keeping the operating system and installed applications up to date also closes off security gaps that attackers rely on.

Using a reputable antivirus solution and running regular scans adds another layer of protection. If you have already opened a suspicious attachment, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the "Insufficient Email Capacity" email letter:

Subject: Security Action Needed on email [recipient's email address]

Insufficient email capacity (over 90% usage)

Hello,
Currently, mail usage has exceeded (90)% of the quota. (SMTP)
Mail quota is 524288000 bytes, and the current usage is 474562205 bytes. (90.52%)

If there is no remaining space in the mailbox, the incoming or outgoing mail may be restricted.

[Update Your Mailbox]

support! Action now 6/9/2026 3:27:04 p.m..
Sincerely,

A fake Gmail login page used in this scam:

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Quick menu:

• What is Insufficient Email Capacity phishing scam?
• Types of malicious emails.
• How to spot a malicious email?
• What to do if you fell for an email scam?

Types of malicious emails:

Phishing Emails

Most commonly, cybercriminals use deceptive emails to trick Internet users into giving away their sensitive private information, for example, login information for various online services, email accounts, or online banking information.

Such attacks are called phishing. In a phishing attack, cybercriminals usually send an email message with some popular service logo (for example, Microsoft, DHL, Amazon, Netflix), create urgency (wrong shipping address, expired password, etc.), and place a link which they hope their potential victims will click on.

After clicking the link presented in such email message, victims are redirected to a fake website that looks identical or extremely similar to the original one. Victims are then asked to enter their password, credit card details, or some other information that gets stolen by cybercriminals.

Emails with Malicious Attachments

Another popular attack vector is email spam with malicious attachments that infect users' computers with malware. Malicious attachments usually carry trojans that are capable of stealing passwords, banking information, and other sensitive information.

In such attacks, cybercriminals' main goal is to trick their potential victims into opening an infected email attachment. To achieve this goal, email messages usually talk about recently received invoices, faxes, or voice messages.

If a potential victim falls for the lure and opens the attachment, their computers get infected, and cybercriminals can collect a lot of sensitive information.

While it's a more complicated method to steal personal information (spam filters and antivirus programs usually detect such attempts), if successful, cybercriminals can get a much wider array of data and can collect information for a long period of time.

Sextortion Emails

This is a type of phishing. In this case, users receive an email claiming that a cybercriminal could access the webcam of the potential victim and has a video recording of one's masturbation.

To get rid of the video, victims are asked to pay a ransom (usually using Bitcoin or another cryptocurrency). Nevertheless, all of these claims are false - users who receive such emails should ignore and delete them.

How to spot a malicious email?

While cyber criminals try to make their lure emails look trustworthy, here are some things that you should look for when trying to spot a phishing email:

• Check the sender's ("from") email address: Hover your mouse over the "from" address and check if it's legitimate. For example, if you received an email from Microsoft, be sure to check if the email address is @microsoft.com and not something suspicious like @m1crosoft.com, @microsfot.com, @account-security-noreply.com, etc.
• Check for generic greetings: If the greeting in the email is "Dear user", "Dear @youremail.com", "Dear valued customer", this should raise suspiciousness. Most commonly, companies call you by your name. Lack of this information could signal a phishing attempt.
• Check the links in the email: Hover your mouse over the link presented in the email, if the link that appears seems suspicious, don't click it. For example, if you received an email from Microsoft and the link in the email shows that it will go to firebasestorage.googleapis.com/v0... you shouldn't trust it. It's best not to click any links in the emails but to visit the company website that sent you the email in the first place.
• Don't blindly trust email attachments: Most commonly, legitimate companies will ask you to log in to their website and to view any documents there; if you received an email with an attachment, it's a good idea to scan it with an antivirus application. Infected email attachments are a common attack vector used by cybercriminals.

To minimise the risk of opening phishing and malicious emails we recommend using Combo Cleaner Antivirus for Windows. 

Example of a spam email:

What to do if you fell for an email scam?

• If you clicked on a link in a phishing email and entered your password - be sure to change your password as soon as possible. Usually, cybercriminals collect stolen credentials and then sell them to other groups that use them for malicious purposes. If you change your password in a timely manner, there's a chance that criminals won't have enough time to do any damage.
• If you entered your credit card information - contact your bank as soon as possible and explain the situation. There's a good chance that you will need to cancel your compromised credit card and get a new one.
• If you see any signs of identity theft - you should immediately contact the Federal Trade Commission. This institution will collect information about your situation and create a personal recovery plan.
• If you opened a malicious attachment - your computer is probably infected, you should scan it with a reputable antivirus application. For this purpose, we recommend using  Combo Cleaner Antivirus for Windows.
• Help other Internet users - report phishing emails to Anti-Phishing Working Group, FBI’s Internet Crime Complaint Center, National Fraud Information Center and U.S. Department of Justice.

Frequently Asked Questions (FAQ)

Why did I receive this email?

These emails are sent out in bulk to large numbers of addresses collected through data breaches, scraped from websites, or harvested through previous scams. There is usually nothing personal about being targeted, and the message is not based on anything specific to your account.

I have provided my personal information when tricked by this email, what should I do?

If you entered your email address and password on the fake page, change that password immediately and do so again for any other account where you reused it. Enabling two-factor authentication on your email account adds an extra layer of protection going forward.

I have downloaded and opened a malicious file attached to an email, is my computer infected?

Executable files can infect a system the moment they are opened. Documents, archives, and similar files usually need an extra step, like enabling macros or running an installer hidden inside, before any malicious code can run.

I have read the email but did not open the attachment, is my computer infected?

No. Simply opening or reading this email does not harm your computer. An infection would only occur if you clicked a link or opened an attachment and then interacted with whatever appeared, such as entering information or enabling content.

Will Combo Cleaner remove malware infections that were present in email attachment?

Combo Cleaner can detect and remove a large number of known malware infections after a full system scan. Some advanced threats may still evade detection, so running periodic scans is recommended for ongoing protection.