Avoid having your email account stolen by the "Roundcube" email scam

Also Known As: Roundcube spam
Damage level: Medium

What is the "Roundcube" email scam?

"Roundcube" email (subject: "- NOTIFICATION - Storage Full") is deceptive message supposedly from Roundcube, a legitimate email service provider. The message claims that recipients have reached their mail storage limit and, unless immediate actions are taken, their accounts will be blocked.

This scheme has no connection to the genuine Roundcube email client and uses the name with malicious intent. This is a phishing scam designed to steal users' email account credentials (log-ins and passwords) to gain full control over the accounts.

Roundcube email email spam campaign

"Roundcube" email scam overview

As its subject implies, "- NOTIFICATION - Storage Full" states that recipients have reached the limit of permissible data storage on their email accounts. According to the system administrator, users' maximum of 99 GB storage space has been used up. Therefore, if they fail to upgrade their accounts, certain features (such as receiving and sending mail) will be disabled.

To upgrade, the message instructs recipients to click a link (provided) to immediately upgrade and raise the storage limit. Once the link is clicked, it opens a seemingly legitimate log-in page. In fact, the goal of this scam is to steal users' email accounts.

Therefore, all information presented in this message is false and any email account credentials entered into this web page are delivered to the scammers. Users who are tricked by this scheme risk more than just losing their email accounts.

Though a compromised email account, other associated accounts might also be accessed/stolen (e.g. social networking and social media, e-commerce [online stores] and others). This allows the individuals behind this scam to make various online purchases, assume recipients' identities and ask their contacts for loans, and so on.

Therefore, this scheme can cause serious privacy issues, financial loss and even identity theft. If attempts to log-in through this phishing site have already been made, you are strongly advised to immediately change the credentials of your email and all connected accounts. Additionally, you are advised to contact official support of all potentially compromised accounts.

Threat Summary:
Name Roundcube Email Scam
Threat Type Phishing, Scam, Social Engineering, Fraud.
Fake Claim Email claims that recipients have reached the storage limit on their email accounts.
Related Domains
Disguise Email is disguised as a message from the Roundcube email service provider.
Symptoms Unauthorized online purchases, changed online account passwords, identity theft, illegal access of the computer.
Distribution methods Deceptive emails, rogue online pop-up ads, search engine poisoning techniques, misspelled domains.
Damage Loss of sensitive private information, monetary loss, identity theft.
Malware Removal (Windows)

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Spam campaigns in general

Deceptive emails are sent by the thousand as parts of operations called "spam campaigns". "Last Warning: Upgrade your email to avoid Shutting Down", "You have 46 Hours in order to make the payment" and "Google winner" are some examples of scam emails proliferated in this fashion.

These messages are typically presented as "official", "priority", "important", "urgent" and similar. These schemes commonly use the names/titles of genuine services, companies organizations, etc. to further give the impression of legitimacy. The only purpose of these messages is to generate revenue for the cyber criminals responsible.

Many tactics are employed to achieve this goal. For example, tricking recipients into providing log-in details of various accounts, revealing personal and sensitive information, making monetary transactions (e.g. fake fees, payments, fines, etc.) and so on.

How do spam campaigns infect computers?

Systems are infected via malicious files attached to, or linked within, deceptive/scam emails. Infectious files come in various formats: archive (RAR, ZIP) and executable (.exe, .run) files, Microsoft Office and PDF documents, JavaScript and others. An infection is triggered by executing, running or otherwise opening a dangerous file.

Once opened, download/installation of trojans, ransomware or other malware begins. To elaborate on how Microsoft Office documents cause infections, they execute malicious macro commands.

In MS Office versions released prior to 2010, this process begins automatically when the document is opened, however, in newer Microsoft Office versions, users are asked to enable macro commands (i.e., editing). Therefore, infections are initiated only if the malicious macros are enabled.

How to avoid installation of malware

To avoid infections caused by malicious content sent in spam campaigns, you are strongly advised not to open suspicious or irrelevant emails. Any attachments or links present in dubious mail must not be opened, as doing so can lead to high-risk infection. Additionally, use Microsoft Office versions released after 2010.

These have "Protected View" mode, which prevents infectious documents from beginning malware download/installation when the file is opened.

Other popular PUA proliferation methods include illegal activation ("cracking") tools, fake updaters and untrusted download sources (e.g. unofficial and free file-hosting websites, Peer-to-Peer sharing networks and other third party downloaders). To ensure system health and user safety, have a reputable anti-virus/anti-spyware suite installed and kept updated.

Furthermore, this software should be used for regular system scans and removal of detected threats/issues. If you have already opened malicious attachments, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the "Roundcube email" email message:

Subject: - NOTIFICATION - Storage Full

Your Email Storage Is Filled Up
Dear -
We write to inform you that you have used up your mail storage limit of 99.0 gigabytes as defined by your system Admin.

You will be blocked from receiving and sending mails if not upgraded today.
Kindly click on the link below for immediate upgrade to receive additional storage space

Warm Regards!
Mail Service Administrator

Client area

Mail Service Blog

Any questions or requests? Create a ticket.

Screenshot of the phishing website to which the link within the "Roundcube" email redirects:

Website the link in Roundcube email scam redirects to

Yet another example of an email from Roundcube spam campaign:

Roundcube email scam (2023-10-03)

Text presented within:

Subject: - Quota Full



Dear -,

Your email quota has reached its maximum storage at 98% and will soon exceed its limit.

Protecting the security of your account is our primary concern, therefore as a preventive measure, we have temporarily limited access to sensitive account features.

To restore your account access, we need you to confirm your identity.

Please follow the secured URL below to proceed with confirming your account information and avoid loss of email data.

Verify My Account

Best Regards

Roundcube Webmail Support

All contents © Copyright 2021 ROUNDCUBE WEBMAIL Corporation. All rights reserved.

Yet another example of an email from Roundcube spam campaign:

Roundcube password expiration email scam (2023-12-07)

Text presented within:

Subject: ACTION REQUIRED: Your webmail password is set to expire today.


Roundcube - Free and Open Source Webmail Software

Hello -,

The passwогd to your mailbox (********) is set to expire today.

Following this prompt, your webmail will log you out and generate a new passwогd.

Alternatively, you can retain and continue using your existing webmail passwогd.

We recommend that you retain your existing password, so you stay logged in across your device(s) and logged sessions;

Keep Existing Passwогd

This email is generated by ascendenciadesign.com's mail server for ********.

Screenshot of the promoted phishing site:

Phishing site promoted via Roundcube password expiration email scam (2023-12-07)

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Quick menu:

Types of malicious emails:

Phishing email icon 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.

Email-virus icon 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 email icon 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:

Example of an email spam

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?

Spam emails are not personal. They are distributed in massive campaigns – hence, thousands of users receive identical messages.

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

If you have provided your account credentials – immediately change the passwords of all potentially exposed accounts and inform their official support. And if you've disclosed other private information (e.g., ID card details, passport scans/photos, credit card numbers, etc.) – contact the appropriate authorities without delay.

I have read a spam email but didn't open the attachment, is my computer infected?

Reading an email is harmless, as devices are infected when malicious attachments/links are opened.

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

If the opened file was an executable (.exe, .run, etc.) – most likely, yes – your system was compromised. However, you might have avoided this if it was a document (.doc, .xls, .one, .pdf, etc.). These formats may need extra actions to jumpstart infection processes, such as enabling macro commands, clicking embedded files/links, etc.

Will Combo Cleaner remove malware infections present in email attachments?

Yes, Combo Cleaner is designed to detect and eliminate all manner of threats. It can remove practically all known malware infections. Note that running a full system scan is essential since high-end malicious software typically hides deep within systems.

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About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

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