How to avoid falling for the "Mailbox Service Upgrade" email scam

What kind of email is "Mailbox Service Upgrade"?

After inspecting this email, we determined that it is a phishing scam. It poses as an automated notification from a mailbox service provider, falsely claiming the recipient's account is due for an upgrade. The scammers want users to click through to a fraudulent website and hand over their email login credentials. Ignore this email to avoid having your account compromised.

"Mailbox Service Upgrade" email scam overview

This email arrives with the subject "security notice. please upgrade mailbox." and presents itself as a routine notification from the recipient's email service. It claims the mailbox is being upgraded with improved performance, better security, and faster access.

Recipients are told to click an "Upgrade Mailbox" button to continue enjoying uninterrupted service. The message creates a false sense of urgency - without acting, users are made to feel they risk losing access to their inbox.

Although the website linked in this email is no longer active, it was designed to mimic a legitimate mailbox login page and collect email credentials. Anything a visitor entered there - a username, password, or recovery details - would have gone directly to the scammers.

Gaining control of an email account gives attackers far more than just inbox access. They can reset passwords for connected services, read private messages, impersonate the victim to contacts, or sell the compromised account on criminal markets.

This scam has no connection to any real email or mailbox service provider. The message is intentionally generic - naming no specific company - so it can reach users of virtually any service.

Similar scam emails in general

In conclusion, this email is a phishing scam disguised as a service upgrade notification from a mailbox provider. It seeks to steal email credentials through a fraudulent website. Recipients should ignore it entirely and avoid clicking any links to protect their accounts from theft. Sometimes, scams like this are also used to distribute malware.

More examples of similar scam emails are Your Message Is Too Large To Be Delivered, cPanel Mailbox Removal, and LinkedIn Collaboration.

How do spam campaigns infect computers?

Spam emails often deliver malware through malicious attachments or embedded links. Common file types include executables, Microsoft Office documents, archives such as ZIP or RAR files, PDFs, and script files. Opening these files - or enabling malicious macro commands in documents - can install malware without the user realizing it.

In other cases, the email contains a link to a malicious website. Visiting the page may trigger an automatic download, or the site may prompt the user to manually run a harmful program. Either way, interaction with the malicious content is what allows the infection to take hold.

How to avoid installation of malware?

Be cautious with emails from unknown or unexpected senders. Do not open attachments or follow links before verifying that the message is legitimate. Scammers frequently disguise malicious emails as service alerts, account notifications, or invoices.

Only download software from official websites and authorized sources. Avoid pirated programs, key generators, and software cracks - these are common methods used to deliver malware.

Keep your operating system and all installed applications up to date, and use a reputable antivirus program with real-time protection. If you have already opened a suspicious attachment, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically remove any threats.

Text presented in the "Mailbox Service Upgrade" email letter:

Subject: security notice. please upgrade mailbox.

Mailbox Service Upgrade

Hello ********

We are pleased to inform you that your mailbox service is being upgraded as part of our ongoing platform improvements and security enhancements.

This upgrade will provide:

Improved mailbox performance
Enhanced security protection
Better storage management
Faster and more reliable access

To continue enjoying uninterrupted access to your mailbox and new service features, please confirm and upgrade your account settings.

[Upgrade Mailbox]

Please complete the upgrade process at your earliest convenience to ensure uninterrupted service access.

Thank you for choosing our services.

Best regards,
******** Support Team

This is an automated notification message. Please do not reply to this email.

2026 Mailbox Services. All rights reserved.

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Quick menu:

• What is Mailbox Service Upgrade 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 types of emails are not personally targeted. Scammers distribute them to large groups at once, sourcing addresses from data breaches, phishing sites, or purchased contact lists. The message is generic by design and sent to as many people as possible.

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

If you entered your email password or other login details, change those credentials immediately on every account where the same password is used. For more sensitive data such as credit card numbers or identification documents, contact the relevant institutions as soon as possible.

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

Executable files (.exe and similar) can compromise the system as soon as they are opened. Document formats such as Word files or PDFs typically require additional interaction - like enabling macros - before malware can activate. The level of risk depends on the file type and how you interacted with it.

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

No. Simply reading or viewing an email without clicking any links or opening attachments cannot infect your device. Interaction with the malicious content is what allows an infection to occur.

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

Combo Cleaner is capable of detecting and removing most known malware. That said, running a full system scan is important - advanced threats sometimes embed themselves deeply and require thorough detection to be fully eliminated.