Avoid losing your email account via "Mailbox Cache Is Full" phishing email

What kind of email is "Mailbox Cache Is Full"?

Our inspection of the "Mailbox Cache Is Full" email revealed that it is spam. This mail operates as a phishing scam targeting recipients' email account log-in credentials (passwords). These spam emails claim that the mailbox cache must be cleared so that the account could operate without problems.

"Mailbox Cache Is Full" email scam overview

The email with the subject "Clear Your Cache" (may vary) is presented as a notification from a mail service provider. It informs the recipient that their mailbox cache is full and must be cleared to resume smooth operations.

When the "Login" button presented in this spam letter is pressed – it results in a redirect to a phishing website. When we visited this site, we learned that it mimics the recipient's email service sign-in page. Despite the website's potentially legitimate appearance – it is fake and designed to record entered information.

The cyber criminals can steal not only the exposed email accounts but also the content registered through them. To elaborate, the criminals can assume the victim's identity and use their social accounts (e.g., emails, social networking, social media, messengers, etc.) to ask the contacts/friends/followers for loans or donations, promote scams, or proliferate malware by sharing malicious files/links.

Furthermore, finance-related accounts (e.g., online banking, money transferring, e-commerce, digital wallets, etc.) can be used to make unauthorized transactions or online purchases.

In summary, by trusting a phishing email like "Mailbox Cache Is Full" – users can experience severe privacy issues, financial losses, and even identity theft.

If you have already entered your log-in credentials into a phishing site – we strongly recommend changing the passwords of all potentially compromised accounts and contacting their official support without delay.

Threat Summary:

Name	"Mailbox Cache Is Full" phishing email
Threat Type	Phishing, Scam, Social Engineering, Fraud
Fake Claim	Recipient's mailbox cache is full and must be cleared.
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)	To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. ▼ Download Combo Cleaner To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Phishing spam campaign examples

"People's Postcode Lottery", "Unknown Browser Login", and "DHL - Your Parcel Delivery Arrived Today" are just a few examples of phishing emails that we have inspected recently. This mail can target a wide variety of information and use different disguises to obtain it.

Spam letters are usually presented as "official", "important", "priority", or similar; they can even be disguised as messages from legitimate organizations, companies, service providers, authorities, and other entities. In addition to facilitating various scams, spam mail is also used to distribute malware (e.g., trojans, ransomware, etc.).

How do spam campaigns infect computers?

Spam emails can have infectious files attached to or linked inside them. These files can be in various formats, e.g., Microsoft Office and PDF documents, executables (.exe, run, etc.), archives (RAR, ZIP, etc.), JavaScript, and so forth.

When such a file is executed, run, or otherwise opened – the infection chain is initiated. For example, Microsoft Office documents infect devices by executing malicious macro commands.

How to avoid installation of malware?

We highly recommend being careful with incoming emails and other messages. The attachments or links found in dubious/irrelevant mail must not be opened since they can be malicious. We advise using Microsoft Office versions released after 2010, as they have the "Protected View" mode that prevents automatic macro execution.

However, malware is not spread exclusively via spam mail. Hence, it is important to download only from official and verified sources. Additionally, all programs must be activated and updated using functions/tools provided by legitimate developers, as illegal activation tools ("cracks") and third-party updaters may contain malware.

Another recommendation is to be vigilant when browsing since fraudulent and dangerous online content typically appears ordinary and innocuous.

We must stress the importance of having a reputable anti-virus installed and kept updated. This software must be used to perform regular system scans and remove detected threats. If you've already opened malicious attachments, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the "Mailbox Cache Is Full" spam email letter:

Subject: Clear Your Cache

Sign In

Email Cache

Hello -,

You are receiving this email because your mailbox cache is full

Please login below to clear your cache so that your mailbox operations can run smoothly.

A confirmatory message will be sent to your inbox afterwards.

Login

© 2022 Webmail Platform, All rights reserved.

Screenshot of the phishing website promoted by the "Mailbox Cache Is Full" spam campaign:

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▼ DOWNLOAD Combo Cleaner By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Quick menu:

• What is "Mailbox Cache Is Full" phishing email?
• 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?

Spam emails are not personal. Cyber criminals distribute them in massive campaigns with the hopes that at least some recipients will fall for their scams.

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

If you have provided account credentials – immediately change the passwords of all potentially exposed accounts and inform their official support. And if the disclosed information was of a different personal nature (e.g., ID card details, 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?

No, merely opening/reading an email will not jumpstart any malware download/installation processes. Systems are infected when malicious attachments or links found in spam mail are opened/clicked.

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

Whether your device was infected might depend on the opened file's format. If it was an executable (.exe, .run, etc.) – most likely, yes. However, you may have avoided an infection if it was a document (.doc, .xls, .pdf, etc.) since these formats might require additional user interaction (e.g., enabling macro commands) to start downloading/installing malware.

Will Combo Cleaner remove malware infections present in email attachments?

Yes, Combo Cleaner can detect and eliminate nearly all known malware infections. It must be mentioned that since high-end malicious programs typically hide deep within systems – running a full system scan is paramount.

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