ICLOUD Outlook Storage Scam Spreads Malware Via Fake Emails
Written by: Stelian
Published on:
A new phishing scam has emerged that targets Outlook users by claiming their ICLOUD storage is almost full. This convincing fake notification states that incoming emails have failed delivery as a result. It then directs victims to malicious attachments disguised as the undelivered messages. Security experts have identified this as a campaign spreading the dangerous Agent Tesla remote access Trojan (RAT). Here’s what you need to know about this scam and how to protect yourself.
Overview of the ICLOUD Outlook Storage Scam
This phishing scam starts with an email that impersonates a warning from ICLOUD about your Outlook email storage. The subject line reads something like “Warning: Mailbox ICLOUD size notification for [your email] (Undelivered Mails Attached).”
The email claims that your ICLOUD-linked Outlook account is nearly full at 96.89% capacity. It states this has caused multiple incoming messages to fail delivery. The scam email goes on to say these undelivered emails are attached, and you should open them to either allow delivery or delete any unwanted messages.
However, the attachments are actually malicious Office documents infected with the Agent Tesla RAT. Once opened, this remote access Trojan secretly infects your computer and allows cyber criminals full access to steal data, install more malware, and spy through your webcam and microphone.
The scam email is designed to look like legitimate notifications from ICLOUD and Outlook. But make no mistake – this is a phishing attempt aimed at stealing personal information and compromising devices with malware.
How the ICLOUD Outlook Storage Scam Works
This scam starts like many phishing attempts – with an email seemingly from a trusted source that urges you to open malicious attachments. Here’s a closer look at how it works:
You receive an email claiming to be from ICLOUD support. The subject line and content are crafted to appear as if ICLOUD is alerting you about an Outlook storage issue. Phrases like “ICLOUD linked to Outlook storage” and mentions of undelivered messages are used to add legitimacy.
The email states your account is nearly full, causing failed deliveries. By claiming your storage is at 96.89% capacity, the scam adds urgency to open the supposed undelivered messages. This is a common phishing tactic to get users to act quickly without thinking.
Malicious Office documents are attached as the “undelivered emails.” Instead of actual messages, the attachments are Excel, Word, or Powerpoint files infected with the Agent Tesla RAT. The extensions may be hidden to further disguise them.
Users are instructed to open the attachments to deliver the emails. The scam email tells you to open the files to either allow the fake messages to be delivered, or delete any unwanted ones. This tricks you into installing the malware.
Agent Tesla infects your computer if you enable macros. The malicious Office documents contain macros that automatically download and install the RAT when enabled. Agent Tesla then has full access to your files, webcam, microphone, and more.
Your personal data is stolen and more malware downloaded. With its remote access, the attackers can silently steal account credentials, financial information, and any other sensitive data. More dangerous malware may also be installed.
This social engineering attack exploits a perceived problem with your Outlook account to trick you into infecting yourself. The urgent tone and legitimate-looking email are designed to bypass scrutiny and get you to open the malicious attachments without realizing the consequences.
What to Do if You Open the Malicious Attachments
If you receive this phishing email and unfortunately open the infected Office document attachments, here are the steps you should take right away:
Disconnect your device from the internet. Unplug your affected computer from the network immediately to prevent further malware communications. Disable WiFi as well.
Scan for malware with antivirus software. Run a full system scan with Malwarebytes to detect Agent Tesla and any other infections. Quarantine or delete any malware it finds.
Reset your Outlook account password. Even if no emails were accessed, resetting your password prevents the attackers from logging in. Enable 2FA if possible.
Contact your email provider. Alert Microsoft, ICLOUD, or any other provider about the phishing attack. They may have additional security recommendations.
Check for unauthorized activity. Review account statements and credit reports to spot any suspicious charges or activity indicating stolen data. Place fraud alerts if needed.
Wipe your device and reinstall the OS. For severe infections, the nuclear option is performing a factory reset and wiping your hard drive before reinstalling the OS. Backup personal files first.
Install antivirus and anti-phishing software. Beef up your security with robust cybersecurity solutions to prevent future attacks. Use tools that block phishing websites and emails.
If Agent Tesla or other malware was installed, take steps immediately to prevent worse damage. Catching and removing the infection quickly can mitigate the fallout. You may have to take more drastic measures though, like wiping your device, if the RAT spent time actively on your system.
Is Your Device Infected? Run a Free Malware Scan
Slow performance, constant pop-ups, or strange behavior? These are classic signs of a malware infection. The fastest way to find out is to scan your device with Malwarebytes Anti-Malware Free — one of the most trusted malware removal tools available.
The free version detects and removes the most common threats, including:
Adware — the cause of those annoying pop-ups
Browser hijackers — unwanted redirects and changed homepages
Trojans and spyware — hidden programs stealing your data
Potentially unwanted programs (PUPs) — software you never asked for
👉 Select your device below — Windows, Mac, or Android — then follow the simple steps to download Malwarebytes, scan your system, and remove any threats it finds. The whole process takes about 5 minutes.
Malwarebytes for WindowsMalwarebytes for MacMalwarebytes for Android
Run a Malware Scan with Malwarebytes for Windows
Malwarebytes is one of the most popular and trusted anti-malware tools for Windows — and it’s completely free for removing infections. It catches threats that many antivirus programs miss, including adware, browser hijackers, and trojans. Follow the steps below to scan and clean your PC in just a few minutes.
Download Malwarebytes
Click the button below to download the latest version of Malwarebytes for Windows from the official source. The free version is all you need — it will scan your computer and remove adware, browser hijackers, and other malicious software at no cost.
(The link opens in a new page where your download will start)
Install Malwarebytes
When the download finishes, open your Downloads folder and double-click the MBSetup file. If Windows shows a User Account Control pop-up, click “Yes” to allow the installation.
Follow the On-Screen Prompts to Install Malwarebytes
The setup wizard will walk you through a few quick screens:
Choose where you’re installing the program — “Personal Computer” or “Work Computer” — then click Next.
Malwarebytes will now install on your device. This usually takes under a minute.
When installation is complete, the “Welcome to Malwarebytes” screen will open automatically.
On the final screen, click Open Malwarebytes to launch the program.
Enable “Scan for Rootkits”
Before scanning, turn on rootkit detection so Malwarebytes can find even the most hidden threats. Click the Settings gear icon on the left side of the screen.
In the settings menu, find “Scan for rootkits” and click the toggle so it turns blue.
Done? Click “Dashboard” in the left pane to return to the main screen.
Start the Scan
Click the blue Scan button. Malwarebytes will automatically update its virus database and start checking your computer for malware.
Wait for the Scan to Finish
The scan checks your entire system for browser hijackers and other malicious programs, so it can take several minutes. Feel free to do something else — just check back occasionally to see the progress.
Quarantine the Detected Threats
When the scan is done, you’ll see a list of everything Malwarebytes found — malware, adware, and potentially unwanted programs. Click the “Quarantine” button to remove all of them at once.
Malwarebytes will now remove the malicious files and registry entries and move them safely into quarantine.
Restart Your Computer
Some threats can only be fully removed after a reboot. If Malwarebytes asks you to restart, click Yes. Once you’re logged back in, your PC is clean and you can continue with the next steps in this guide.
When the scan finishes, click Quarantine to remove everything Malwarebytes found. That’s it — your Windows PC is now clean of trojans, adware, and other malware, and should be back to running smoothly.
If your current antivirus allowed this malicious program on your computer, you may want to consider purchasing Malwarebytes Premium to protect against these types of threats in the future. If you are still having problems with your computer after completing these instructions, then please follow one of the steps:
Malwarebytes for Mac is a free on-demand scanner that removes the malware other security software tends to miss — adware, browser hijackers, and unwanted programs included. Cleaning an infected Mac with Malwarebytes has always been completely free, and it’s our go-to recommendation. Follow the steps below to scan and clean your Mac in just a few minutes.
Download Malwarebytes for Mac
Click the button below to download the latest version of Malwarebytes for Mac.
When the download finishes, open your Downloads folder and double-click the setup file to begin the installation.
Follow the On-Screen Prompts to Install Malwarebytes
The Malwarebytes for Mac Installer will guide you through a few quick screens. Click “Continue” and keep following the prompts until the installation completes.
When the installation is complete, Malwarebytes opens to the Welcome to Malwarebytes screen. Click “Get started“.
Select “Personal Computer” or “Work Computer”
Malwarebytes will ask what type of computer you’re installing it on. Click either Personal Computer or Work Computer, whichever applies.
Start the Scan
Click the “Scan” button. Malwarebytes will automatically update its detection database and begin checking your Mac for malware.
Wait for the Scan to Finish
Malwarebytes will scan your Mac for adware, browser hijackers, and other malicious programs. This can take a few minutes, so feel free to do something else — just check back occasionally to see the progress.
Quarantine the Detected Threats
When the scan is done, you’ll see a list of everything Malwarebytes found. Click the “Quarantine” button to remove all the threats at once.
Restart Your Mac
Malwarebytes will now remove all the malicious files it found. Some threats can only be fully removed after a reboot — if Malwarebytes asks you to restart, allow it. Once you’re logged back in, your Mac is clean.
Once the scan is done, remove every threat it detected. Your Mac is now free of adware, rogue browser extensions, and other potentially harmful software.
If your current antivirus allowed a malicious program on your computer, you might want to consider purchasing the full-featured version of Malwarebytes Anti-Malware to protect against these types of threats in the future. If you are still experiencing problems while trying to remove a malicious program from your computer, please ask for help in our Mac Malware Removal Help & Support forum.
Run a Malware Scan with Malwarebytes for Android
Malwarebytes for Android automatically detects and removes dangerous threats like malware and ransomware so you don’t have to worry about your most-used device being compromised. Aggressive detection of adware and potentially unwanted programs keeps your Android phone or tablet running smooth.
Download Malwarebytes for Android.
You can download Malwarebytes for Android by clicking the link below.
In the Google Play Store, tap “Install” to install Malwarebytes for Android on your device.
When the installation process has finished, tap “Open” to begin using Malwarebytes for Android. You can also open Malwarebytes by tapping on its icon in your phone menu or home screen.
Follow the on-screen prompts to complete the setup process
When Malwarebytes will open, you will see the Malwarebytes Setup Wizard which will guide you through a series of permissions and other setup options. This is the first of two screens that explain the difference between the Premium and Free versions. Swipe this screen to continue. Tap on “Got it” to proceed to the next step. Malwarebytes for Android will now ask for a set of permissions that are required to scan your device and protect it from malware. Tap on “Give permission” to continue. Tap on “Allow” to permit Malwarebytes to access the files on your phone.
Update database and run a scan with Malwarebytes for Android
You will now be prompted to update the Malwarebytes database and run a full system scan.
Click on “Update database” to update the Malwarebytes for Android definitions to the latest version, then click on “Run full scan” to perform a system scan.
Wait for the Malwarebytes scan to complete.
Malwarebytes will now start scanning your phone for adware and other malicious apps. This process can take a few minutes, so we suggest you do something else and periodically check on the status of the scan to see when it is finished.
Click on “Remove Selected”.
When the scan has been completed, you will be presented with a screen showing the malware infections that Malwarebytes for Android has detected. To remove the malicious apps that Malwarebytes has found, tap on the “Remove Selected” button.
Restart your phone.
Malwarebytes for Android will now remove all the malicious apps that it has found. To complete the malware removal process, Malwarebytes may ask you to restart your device.
After the scan, tap Remove Selected to delete all detected threats. Your Android phone is now clean — no more malicious apps, adware, or browser redirects.
If your current antivirus allowed a malicious app on your phone, you may want to consider purchasing the full-featured version of Malwarebytes to protect against these types of threats in the future. If you are still having problems with your phone after completing these instructions, then please follow one of the steps:
Restore your phone to factory settings by going to Settings > General management > Reset > Factory data reset.
Now that your device is clean, keep it that way. Most infections start with a malicious ad or a fake download button — so blocking them at the source is your best defense.
We recommend AdGuard, which blocks malicious ads, phishing pages, and dangerous redirects before they can reach you.
Frequently Asked Questions about the ICLOUD Outlook Storage Scam
What is the ICLOUD Outlook storage scam?
This is a phishing scam where victims receive an email claiming their Outlook account linked to ICLOUD is almost full. It states this caused undelivered messages that are attached to the email. However, the attachments contain malware.
How does the scam email look believable?
The scam uses official logos and urgent wording about failed deliveries due to full storage. This tricks users into thinking ICLOUD sent it. The attachments are disguised as undelivered messages.
What happens if I open the attachments?
The Office document attachments contain macros that install the Agent Tesla remote access Trojan. This gives hackers control of your computer to steal data, install more malware, and spy through your webcam.
Should I click any links in the scam email?
No, the email contains no legitimate links. Any links are likely phishing sites or additional malware. Never click links or attachments from suspicious emails.
How do I tell this is fake and not real ICLOUD mail?
Real notifications from ICLOUD would not claim you have undelivered messages in a separate attachment. Unexpected attachments are a red flag. ICLOUD also doesn’t mention macros.
What should I do if I enabled macros from the attachment?
Immediately disconnect your device from all networks. Run antivirus scans to remove any malware installed. Also reset your Outlook password and contact ICLOUD support about the phishing attack.
How can I protect myself from this scam?
Watch for urgent emails with attachments from ICLOUD or Microsoft. Verify messages by contacting support. Never enable macros in documents from people you don’t know. Use antivirus software and be cautious.
What should I do if I think someone is accessing my account?
If you see unauthorized activity, immediately change your Outlook password and enable two-factor authentication. Review account statements for any unknown charges indicating stolen financial data. Place fraud alerts on your name if identity theft is suspected.
Conclusion: Stay Vigilant Against Outlook Phishing Scams
Email scams targeting popular services like Outlook continue to grow in sophistication. This ICLOUD storage phishing campaign leverages timely social engineering to bypass user defenses. The urgent tone plus official-looking message tricks unwitting victims into installing sophisticated malware like Agent Tesla.
Stay vigilant against these types of phishing attempts. Warning signs include unexpected attachments, threats about account access being lost, and requests to enable macros. When in doubt, contact the service provider directly to confirm strange emails. Backups, antivirus software, and password managers are also essential precautions against phishing.
With attention and sound cybersecurity practices, users can better identify and stop these malicious attacks in their tracks. Don’t let emergent phishing scams like this Outlook impersonation fool you – be cautious about what links you click and attachments you open. Your data and device security depend on it.
10 Rules to Avoid Online Scams
Here are 10 practical safety rules to help you avoid malware, online shopping scams, crypto scams, and other online fraud. Each tip includes a quick “if you already got hit” action.
Stop and verify before you click, log in, download, or pay.
Most scams win by creating urgency. Verify using a trusted method: type the website address yourself, use the official app, or call a known number (not the one in the message).
If you already clicked: close the page, do not enter passwords, and run a malware scan.
Keep your operating system, browser, and apps updated.
Updates patch security holes used by malware and malicious ads. Turn on automatic updates where possible.
If you saw a scary “update now” pop-up: close it and update only through your device settings or the official app store.
Use layered protection: antivirus plus an ad blocker.
Antivirus helps block malware. An ad blocker reduces scam redirects, phishing pages, and malvertising.
If your browser is acting weird: remove unknown extensions, reset the browser, then run a full scan.
Install apps, software, and extensions only from official sources.
Avoid cracked software, “keygens,” and random downloads. During installs, choose Custom/Advanced and decline bundled offers you do not recognize.
If you already installed something suspicious: uninstall it, restart, and scan again.
Treat links and attachments as untrusted by default.
Phishing often impersonates delivery services, banks, and popular brands. If it is unexpected, do not open attachments or log in through the message.
If you entered credentials: change the password immediately and enable 2FA.
Shop safely: research the store, then pay with protection.
Be cautious with brand-new stores, “closing sale” stories, and prices that make no sense. Prefer credit cards or PayPal for dispute options. Avoid wire transfers, gift cards, and crypto payments.
If you already paid: contact your card issuer or PayPal quickly to dispute the transaction.
Crypto rule: never pay a “fee” to withdraw or recover money.
Common patterns include fake profits, then “tax,” “gas,” or “verification” fees. Another is a “recovery agent” who demands upfront crypto.
If you already sent crypto: stop paying, save evidence (wallet addresses, TXIDs, chats), and report the scam to the platform used.
Secure your accounts with unique passwords and 2FA (start with email).
Use a password manager and unique passwords for every account. Enable 2FA using an authenticator app when possible.
If you suspect an account takeover: change passwords, sign out of all devices, and review recent logins and recovery settings.
Back up important files and keep one backup offline.
Backups protect you from ransomware and device failure. Keep at least one backup on an external drive that is not always connected.
If you suspect infection: do not connect backup drives until the system is clean.
If you think you are a victim: stop losses, document evidence, and escalate fast.
Move quickly. Speed matters for disputes, account recovery, and limiting damage.
Stop payments and contact: do not send more money or respond to the scammer.
Call your bank or card issuer: block transactions, replace the card if needed, and start a dispute or chargeback.
Secure your email first: change the email password, enable 2FA, and remove unfamiliar recovery options.
Secure other accounts: change passwords, enable 2FA, and log out of all sessions.
Scan your device: remove suspicious apps or extensions, then run a full malware scan.
Save evidence: screenshots, emails, order pages, tracking pages, wallet addresses, TXIDs, and chat logs.
Report it: to the payment provider, marketplace, social platform, exchange, or wallet service involved.
These rules are intentionally simple. Most online losses happen when decisions are rushed. Slow down, verify independently, and use payment methods and account controls that give you recourse.
About Stelian
Stelian leverages over a decade of cybersecurity expertise to lead malware analysis and removal, uncover scams, and educate people. His experience provides insightful analysis and valuable perspective.