Avoid malware infections from emails offering free COVID-19 tests

What is the "COVID-19 test" email?

"COVID-19 test" is yet another Coronavirus/COVID-19-themed spam email campaign. There are several variants of these deceptive emails, however, the common thread is that they all offer free coronavirus testing to recipients.

The messages claim that the attached files are forms/applications, however, the Excel spreadsheets initiate an infection chain: download/installation of the TrickBot Trojan. The primary purpose of this malware is to steal data such as banking information, cryptowallets and other private data.

As mentioned, there are multiple versions of "COVID-19 test" emails. They are thematically identical and, while the text differs, some of the sentences are copied and/or reused with slight modification.

The researched variants were entitled "Are you scared of covid-19? Take action today?", "Are you really scared of coronavirus (covid-19)? Make something now.", and "Are you afraid of covid-19? Act immediately?" respectively.

The emails begin by stating that as the COVID-19 pandemic is spreading and that the sender's medical team ("U.S Humanitarian Team") is offering free coronavirus tests. The messages reassure people that this is a genuine research/investigation effort and not a scam.

To obtain the free tests at the nearest healthcare facility, recipients are instructed to complete the attached request application and return it to the same email address. Furthermore, the attachment supposedly contains medical specialist approved recommendations and other safety tips.

Note that all information provided in the "COVID-19 test" emails is false and merely bait to trick recipients into opening the infectious document attached to them. Once opened, the Excel spreadsheet entitled "CoVid19_Form_v0101 [Group].xls" sates that the data within the document is locked and will remain in this state until the "Enable" button is clicked.

Should these instructions be followed, however, the TrickBot malware infection process begins. The presence of this Trojan on systems can lead to serious problems such as financial loss, serious privacy issues and identity theft. Therefore, you are strongly advised against trusting the "COVID-19 test" scam emails.

If it is known or suspected that TrickBot has already infected the system, use anti-virus software to eliminate it immediately.

"Australian Government Department of Health", "COVID-19 Relief", "COVID-19 Insurance Plan From CIGNA", and "COVID-19 Part Time Employment" are some examples of other Coronavirus/COVID-19-themed scam emails. These messages are distributed by the thousand during large scale operations termed "spam campaigns".

This mail can have many disguises and is usually presented as "official", "urgent", "important" or similar. Malware proliferation is not the only purpose of spam campaigns. Phishing emails are a likewise a common occurrence. Regardless of what these scams claim, request or demand, the purpose is identical: to generate revenue for the designers.

How did "COVID-19 test Email Virus" infect my computer?

Infections are caused through dangerous files sent distributed via spam campaigns. The malicious content can be attached to emails or, alternatively, the messages can contain downloads links to this software. Infectious files can be in various formats such as archives (ZIP, RAR), executables (.exe, .run), Microsoft Office and PDF documents, JavaScript, etc.

When these files are executed, run or otherwise opened, the infection process is triggered. For example, MS Office documents infect systems by executing malicious macro commands.

In Microsoft Office versions released before 2010, this process is automatically started when a file is opened, however, in newer versions, users are asked to enable macros (i.e., to enable editing/content) - therefore, malware download/installation begins only after the macro commands are manually enabled.

How to avoid installation of malware

Do not open dubious or irrelevant emails, especially those received from suspect/unknown senders (addresses). Use Microsoft Office versions released after 2010, since they have "Protected View" mode, which prevents malicious macros from starting any infection processes when dangerous documents are opened.

Malware is also distributed via untrusted download sources (e.g. unofficial and free file-hosting websites, Peer-to-Peer sharing networks and other third party downloaders), illegal activation tools ("cracks") and fake updates. Therefore, use only official/verified download channels and activate and update programs with tools/functions provided by legitimate developers.

To ensure device and user safety, have a reputable anti-virus/anti-spyware suite installed. Keep this software up to date, and use it to run regular system scans and to remove threats/issues. If you have already opened "COVID-19 test Email Virus" attachment, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Text presented in the "COVID-19 test" email message:

Subject: Are you scared of covid-19? Take action today?

 

Hi,

 

Given that the coronavirus(covid-19) pandemic spreads, our medical crew is here for helping people exactly like you to obtain Coronavirus covid-19 text without spending a dime. This is a period for self-assurance, not stress. Research, not trick.
Check and fill out the form enclosed and provide us with a reply to this email to obtain your personal coronavirus check today at your nearby medical center.

 

You will additionally discover all instructions to stay safe in the outbreak. Follow these simply yet practical actions recommended by medical regulators.

 

Most sincerely, **************
USA Humanitarian Squad,
*************
US 501(c)(3) non-profit organization

Screenshot of another "COVID-19 test" email variant:

Text presented in this message:

Subject: Are you really scared of coronavirus (covid-19)? Make something now.

 

Good day,

 

Given that the coronavirus(covid-19) disease grows, our medical team is here to guide citizens just like you to obtain Covid-19 check for free. This is certainly a period of time for confidence, not emotional stress. Research, not trick.
Find and complete the application request enclosed and give us a reply to this letter to obtain your personal covid-19 check now at your local healthcare facility.

 

You will additionally discover all methods to remain safe during the pandemic. Please follow these simply but useful tips suggested by medical specialists.

 

Regards, *****************
U.S Humanitarian Team,
*************
United States 501(c)(3) non-profit organization

Screenshot of yet another "COVID-19 test" email variant:

Text presented in this message:

Subject: Are you afraid of covid-19? Act immediately?

 

Hello there,

 

Given that the coronavirus disease spreads, our team comes for giving people exactly like you to obtain Coronavirus Covid-19 check at absolutely no cost. This really is time for self-assurance, not pressure. Investigation, not trick.
Discover and complete the application request linked and provide us with a reply to this email to obtain your own personal coronavirus covid-19 test today at your closest clinic.

 

You will furthermore find all recommendations to stay safe while in the outbreak. Follow all these easy yet useful tips recommended by medical regulators.

 

Sincerely, ******************
USA Humanitarian Team
US 501(c)(9) non-profit organization

Malicious attachment distributed via "COVID-19 test" spam campaign ("CoVid19_Form_v0101 [Group].xls"):

Instant automatic malware removal:

Manual threat removal might be a lengthy and complicated process that requires advanced IT skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:

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.

Types of malicious emails:

If you opened an attachment or downloaded a file from a suspicious email, run a full system scan with Combo Cleaner. If you only received the email and didn't engage with it, you don't need to scan anything - just identify the scam and delete it. The full procedure below covers both situations and what to do if you already clicked, replied, or sent money.

Credential theft Phishing emails

Fake login pages disguised as PayPal, Microsoft, Apple, banks, or social networks. The email pushes a link to a near-perfect copy of the real login screen. The moment you type your username and password, the attacker has them.

Common subject lines

• "Action required: confirm your account"
• "Your password expires today"
• "Unusual sign-in attempt detected"
• "Verify your billing information"

Malware delivery Emails with malicious attachments

Trojans hidden inside fake invoices, faxes, shipping confirmations, or Office documents. Opening the attachment runs the payload and infects the system - often with an info-stealer or remote-access trojan.

Common subject lines

• "Invoice INV-2026-XXXX attached"
• "Fax received - 3 pages"
• "Your shipping document is ready"
• "Voicemail from +1-XXX-XXX-XXXX"

Extortion Sextortion emails

Fake claims of webcam recordings demanding cryptocurrency. Almost always a bluff: the attacker pulls a real password from an old data breach to make the threat look credible, then claims to have video of you. They have no recording and no access.

Common subject lines

• "I know your password is XXXX"
• "Your account has been hacked"
• "I have recorded you - 48 hours to pay"
• "You have been compromised"

Callback fraud Refund & callback scams

"Your subscription was renewed for $499 - call to cancel." Norton, McAfee, Geek Squad, PayPal, and Wells Fargo variants are all common. There's no real subscription. The phone number in the email connects directly to the scammer, who walks you through "refunding" yourself - which is actually them stealing money from your bank.

Common subject lines

• "Norton subscription auto-renewed - $499.99"
• "McAfee Total Protection invoice"
• "Geek Squad order confirmation"
• "Your PayPal payment is being processed"

Credential theft Account suspension & verification scams

"Your account will be deleted in 24 hours - verify now." The artificial deadline is the whole point: it pressures you to click before checking details. The "verify" link goes to a phishing page styled to look like the real provider.

Common subject lines

• "Your account will be deleted in 24 hours"
• "Suspicious activity detected - verify now"
• "Final warning: account closure"
• "Action required to keep your account active"

Mixed payload Delivery & package scams

Fake DHL, USPS, UPS, or FedEx tracking, customs fees, or "package undeliverable" notices. Targets anyone expecting a parcel - the timing alone catches many people. The link hides either phishing (asking for card details to "release" the package) or a malware download.

Common subject lines

• "Your DHL package is held at customs"
• "USPS - delivery attempt failed"
• "FedEx tracking update - action required"
• "Pay $2.99 redelivery fee to release your parcel"

Remote access Tech support scams

Fake Microsoft, Apple, or "Windows Defender" security alerts pushing a phone number. Real Microsoft and Apple never email a phone number to call. The number connects you to a scammer who asks for remote access to "fix" the imaginary problem and then demands payment.

Common subject lines

• "Microsoft Defender expired - renew now"
• "Apple ID security alert"
• "Critical: virus detected on your PC"
• "Windows license expired - call now"

Wire fraud Advance-fee scams

Inheritance, lottery wins, romance, or business deals that ask for a small fee to release a much larger sum. The classic "Nigerian prince" 419 family of frauds. Once you pay the first fee, more fees appear (taxes, lawyer, transfer charges) until you stop paying. The promised money never exists.

Common subject lines

• "Inheritance from a relative you didn't know about"
• "You won the international lottery"
• "URGENT - business proposal worth $XX million"
• "Compensation fund release for fraud victims"

Wire fraud Business email compromise (BEC)

CEO impersonation asking employees to wire money or buy gift cards, or fake supplier invoices with newly "updated" bank details for payment redirection. The email often spoofs a real internal executive's display name and uses an external lookalike domain.

Common subject lines

• "Quick task - need you to buy gift cards"
• "Updated banking details for invoice payment"
• "Wire transfer request - urgent"
• "Are you available?" (CEO impersonation opener)

How to spot a malicious email?

Phase 1~ 2 min

Spot - identify the red flags

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1

Check the sender's actual address, not the display name

30 sec

The display name (the human-readable part) is trivial to fake. Always check the full address that comes after it. Common red flags:

• Domain mismatch - service@paypa1.com, support@micros0ft-help.com, look-alike domains using digits or extra hyphens
• Free-email impersonation - any "official" message from a bank, courier, or platform sent from a @gmail.com, @outlook.com, or @yahoo.com address
• Reply-To mismatch - the From address looks legitimate but Reply-To points somewhere completely different

Why this matters

Real companies own their domains and send mail from them. A "DHL" message from a Gmail address is never legitimate, regardless of how convincing the body looks.

2

Watch for urgency, threats, and generic greetings

30 sec

Scams almost always rush you. The point is to make you act before you think. Treat any of the following as a strong signal:

• "Your account will be deleted in 24 hours"
• "Final notice" / "Immediate action required"
• "Dear Customer" or "Dear User" instead of your real name
• Threats of fines, account closure, legal action, or arrest
• Promises of refunds, prizes, or money you didn't earn
• Spelling and grammar mistakes in messages claiming to come from a major brand

3

Hover over every link before clicking

30 sec

On a desktop, hover the mouse over the link without clicking. The real destination shows in the bottom-left status bar of your browser or email client. On a phone, long-press the link to preview the URL.

• Real Microsoft, PayPal, or bank links go to those exact domains, not redirects through unrelated sites
• Shortened URLs (bit.ly, tinyurl, t.co) hide the real destination - never click them in unsolicited mail
• The visible link text and the actual URL must match - mismatches are the single biggest phishing red flag

Pro tip

When in doubt, don't click the link. Open a new browser tab and type the company's address yourself, then log in normally. If there really is an issue with your account, you'll see it there.

4

Treat unexpected attachments as hostile

30 sec

If you didn't ask for the file, don't open it - even if it appears to come from someone you know. Categories that should never be opened from email without verification through another channel:

• .exe, .scr, .iso, .img, .vbs, .bat - executables, never legitimate attachments
• .docx, .xlsx, .pptx with "Enable macros" prompts - the macros run the malware
• .pdf with "Click here to view" buttons - usually a phishing redirect, not a real document
• .zip, .rar, .7z archives, especially password-protected ones - the password defeats the email scanner

Phase 2~ 2 min

Report and delete - if you haven't engaged

---

If you only received the email and didn't reply, click, or open anything, the steps below are all you need. Your computer is not infected.

5

Don't reply, don't click "unsubscribe"

30 sec

Replying confirms your address is real and monitored, which gets you added to higher-value scam lists. The "unsubscribe" link in a scam message is rarely a real opt-out - it usually leads to a phishing page or downloads a tracking pixel.

Instead, mark the message as junk or phishing inside your email client (this trains the spam filter), then block the sender.

6

Report the scam to your email provider and authorities

1 min

Inside your email client:

• Gmail: open the message → ⋮ menu → Report phishing
• Outlook / Outlook.com: ⋯ menu → Report → Report phishing
• Apple Mail / iCloud: Move to Junk, then forward to reportphishing@apple.com

Forward or report to authorities:

• International: forward to reportphishing@apwg.org
• United States: ic3.gov (FBI)
• United Kingdom: forward phishing emails to report@phishing.gov.uk (NCSC SERS); for financial loss report at reportfraud.police.uk (Report Fraud, the successor to Action Fraud; 0300 123 2040)
• Canada: antifraudcentre.ca
• Australia: scamwatch.gov.au
• EU: your national CERT - find yours via the ENISA CSIRT map

After reporting, delete the email and empty the Trash folder so you don't accidentally open it later.

Phase 3~ 10–60 min

Recover - if you already engaged with the scam

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Pick the step below that matches what you did. If multiple apply, work through them in the order they appear - the steps are arranged from lowest to highest risk.

7

You only clicked a link (didn't enter anything or download anything)

Scenario: clicked link only10 min

Close the page right away. Don't enter any information, even if the page looks legitimate.

• Clear your browser cache and cookies for the last hour - Chrome/Edge: Ctrl+Shift+Del → Last hour → check Cookies and Cached files
• Run a quick scan with Combo Cleaner in case the page tried to drop a file silently (drive-by download)
• Update your browser to the latest version - most drive-by exploits target outdated browsers
• Watch for new browser pop-ups, redirects, or unfamiliar notifications over the next few days

Why this matters

Modern browsers block most drive-by attacks, but a single click on a phishing page can still be enough on an outdated browser or unpatched plugin. A quick scan catches anything that landed silently.

8

You opened an attachment or downloaded a file - run a full malware scan

Scenario: opened attachment⚠ Highest risk60–90 min

Opening an attachment is the most common path to actual infection. Treat the system as compromised until the scans below come back clean. Work through these sub-steps in order:

8.1Disconnect from the network

Unplug Ethernet and turn off Wi-Fi. If the attachment was an info-stealer or remote-access trojan, this stops it from sending data out or receiving commands. Keep the network off until you've booted into Safe Mode (next step) - you'll reconnect there briefly to download the scanners.

8.2Boot into Safe Mode with Networking, then download the scanners

Windows 11: Settings → System → Recovery → Advanced startup → Restart now → Troubleshoot → Advanced options → Startup Settings → Restart → press 5 or F5.

Windows 10: hold Shift, click Power → Restart → Troubleshoot → Advanced options → Startup Settings → Restart → press F5.

Once Safe Mode has loaded, turn Wi-Fi back on and download Combo Cleaner (used in 8.4) and Microsoft Safety Scanner (used in 8.5). Safe Mode loads only minimal drivers, so most malware can't auto-run while you're getting the tools. Save both installers to your Desktop.

8.3Run Microsoft Defender Offline

Reboot to normal Windows. Open Windows Security → Virus & threat protection → Scan options. Select Microsoft Defender Antivirus (offline scan) and click Scan now. The PC restarts into a stripped-down environment and scans the disk before Windows fully loads - this is what catches rootkits and bootkits.

Recommended antivirus

Combo Cleaner

VB100 certified. Includes anti-trojan, registry/persistence scanning, and anti-spyware in one pass. The 7-day free trial is available.

Download Combo Cleaner

8.4Run a full Combo Cleaner scan

Install Combo Cleaner and run a full system scan (not the quick scan). Let it complete fully, review what it found, and apply the recommended actions. Combo Cleaner will quarantine known trojans and remove their persistence in the registry.

8.5Run Microsoft Safety Scanner as a second-opinion scan

Download Microsoft Safety Scanner (MSERT.exe). The binary expires every 10 days, which means every download has the latest signatures. Run a full scan after Combo Cleaner to catch anything one engine alone might miss.

8.6Reset browsers and clear notification permissions

Many email-borne trojans drop adware that hijacks browsers. Reset each browser you use:

Chrome: chrome://settings/reset → Restore settings to their original defaults. Then chrome://settings/content/notifications - remove unfamiliar sites.

Edge: edge://settings/reset. Then edge://settings/content/notifications.

Firefox: about:support → Refresh Firefox.

8.7Re-enable Defender, Tamper Protection, and update everything

Open Windows Security → Virus & threat protection → Manage settings and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all on. Then run Settings → Windows Update → Check for updates and update browsers and applications.

Important

If the scans keep finding new threats on each run, or files reappear after deletion, you may have a deeper compromise that needs a clean Windows reinstall. See pcrisk's full manual malware removal guide for the extended procedure (Process Explorer, Autoruns, hosts file inspection).

9

You entered credentials on a fake login page

Scenario: shared password⚠ Act fast20 min

Assume the attacker has your password and is using it right now. Speed matters.

1. Change the password from a different, known-clean device (your phone is fine if it's not infected). Don't reuse the old password anywhere else.
2. Enable two-factor authentication if you haven't already. Prefer an authenticator app or hardware key over SMS.
3. Sign out of all sessions - most platforms have a "sign out everywhere" option in security settings, which kicks the attacker out.
4. Review recent activity - look for unfamiliar logins, new devices, forwarding rules, or app permissions. Remove anything you don't recognize.
5. Check your other accounts - if you reused that password anywhere else, change it there too. Check your exposure at haveibeenpwned.com.
6. Update security questions - the attacker may have seen the answers in your account profile.

Why email comes first

If you only have time to change one password, change your primary email password - it's the recovery hub for every other account. An attacker who controls your email can reset everything else.

10

You sent money or shared bank, card, or ID details

Scenario: financial loss⚠ Contact bank now30 min

Time is the single biggest factor in recovering money. Banks can sometimes recall a wire or reverse a card transaction within the first few hours.

1. Call your bank or card issuer immediately. Use the number on the back of the card, not any number from the scam email. Ask them to freeze the card, reverse the transaction if possible, and flag the account for fraud monitoring.
2. If you sent a wire transfer or used a money-transfer service (Western Union, MoneyGram, Zelle, Wise), call them directly and request a recall. Some can be reversed within minutes if reported fast.
3. If you sent cryptocurrency or gift cards, recovery is unlikely - but report it anyway, since law enforcement tracks these patterns.
4. File a police report. You'll need the report number for any insurance, bank, or credit-bureau claim. Save the report number.
5. File with the right authority for your country:
   • US: ic3.gov + reportfraud.ftc.gov
   • UK: reportfraud.police.uk (Report Fraud, the successor to Action Fraud; 0300 123 2040)
   • Canada: antifraudcentre.ca
   • Australia: scamwatch.gov.au
   • EU: your national CERT or police cybercrime unit
6. Set fraud alerts on all major credit bureaus if you shared any ID details. US: Equifax, Experian, TransUnion. UK: Experian, Equifax, TransUnion (Cifas Protective Registration is a stronger option).
7. Save all evidence - the original email (with full headers), screenshots of the fake site, transaction records, any phone numbers or chat logs.

Phase 4~ 15 min + 30 days

Verify & monitor

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11

Final scan and startup-app check

15 min

Reconnect to the network and run one final full scan with Combo Cleaner, followed by a Windows Defender quick scan. Then open Task Manager (Ctrl + Shift + Esc) and switch to Startup apps - disable anything unfamiliar.

Make sure Windows, browsers, and any applications you use are fully up to date. The infection vector that worked on you once usually involves outdated software.

12

Monitor accounts and credit for 30 days

5 min/day · 30 days

Most fraud follow-ups land in the first month. Until that window closes, keep watching:

• Bank and card statements - daily for the first week, then weekly
• Email - watch for password-reset confirmations or login alerts you didn't trigger
• Credit report - US: free at annualcreditreport.com; UK: Experian, Equifax, TransUnion all have free tiers
• Breach alerts - sign up at haveibeenpwned.com to be notified when your email appears in new leaks

If anything new appears in any of those, treat it as a continuing compromise: change passwords again, contact the bank again, and update the police report.

Important: If you didn't click anything, didn't reply, and didn't open any attachment, your computer is not infected - just delete the email and move on. If you opened an attachment or downloaded a file, run an automated scan with Combo Cleaner and Windows Defender and stop there. That path catches the vast majority of email-borne malware without the risk of breaking Windows by deleting the wrong file.