Do not trust sites claiming "Operating System Blocked Due To Questionable Activity"

Also Known As: "Operating System Blocked Due To Questionable Activity" tech support scam
Damage level: Medium

What kind of scam is "Operating System Blocked Due To Questionable Activity"?

While investigating suspicious websites, our researchers discovered the "Operating System Blocked Due To Questionable Activity" technical support scam. The aim of this deceptive content is to trick users into calling fake Microsoft support in order to unblock their device and resolve other potential issues.

It must be stressed that all the information provided by this scam is false, and it is in no way associated with Windows or its developer – Microsoft.

Operating System Blocked Due To Questionable Activity scam

"Operating System Blocked Due To Questionable Activity" scam overview

The webpage running this scam is disguised as Microsoft's official website. Upon access, it presents the visitor with multiple pop-up windows. The information therein warns of various bogus threats and issues present on the user's device. The scam continuously urges to call the provided helpline.

How the scheme progresses once the scammers are contacted can vary. Typically, the victim is asked to allow the "expert technicians", "Microsoft support", etc., to access their computer remotely. The connection can be established using legitimate software, such as UltraViewer, TeamViewer, AnyDesk, etc.

After the device is accessed, cyber criminals can cause a wide variety of damage while continuing the pretense of performing malware removal or other services. For example, the criminals can disable or uninstall genuine security tools, install fake anti-viruses, obtain sensitive information, and even infect the system with actual malware (e.g., trojans, ransomware, cryptominers, etc.).

Targeted data usually includes: log-in credentials (e.g., emails, social networking, social media, e-commerce, online banking, cryptowallets, etc.), personally identifiable information (e.g., ID card details, passport scans/photos, etc.), and finance-related data (e.g., banking account details, credit card numbers, etc.).

The victim can be deceived into disclosing this sensitive information over the phone or entering it into phishing files/websites. Stealer-type malware can also be used for this purpose.

What is more, tech support scammers ask for exorbitant payments. Criminals tend to use difficult-to-trace methods for obtaining funds, e.g., cryptocurrencies, gift cards, pre-paid vouchers, or cash hidden in packages and shipped. Utilizing such methods decreases the chances of persecution and victims retrieving their funds. It is pertinent to mention that successfully scammed victims are often targeted repeatedly.

To summarize, by trusting a scam like "Operating System Blocked Due To Questionable Activity" – users can experience system infections, data loss, severe privacy issues, significant financial losses, and even identity theft.

Should it be impossible to exit a deceptive webpage – use the Windows Task Manager to terminate the browser's process. When reaccessing the browser, do not restore the previous browsing session, as that will reopen the scam page.

If you have allowed cyber criminals to access your device remotely – you must first disconnect it from the Internet. Afterward, remove the remote access program that the criminals used since they may not need your consent to reconnect. Lastly, perform a full system scan with an anti-virus and remove all detected threats.

If you have provided your log-in credentials to scammers – change the passwords of all potentially compromised accounts and inform their official support. If you have disclosed other private data (e.g., ID card details, passport photos/scans, credit card numbers, etc.) – contact the appropriate authorities without delay.

Threat Summary:
Name "Operating System Blocked Due To Questionable Activity" tech support scam
Threat Type Phishing, Scam, Social Engineering, Fraud
Fake Claim Visitor's device has been blocked due to various potential threats present on it.
Disguise Microsoft
Tech Support Scammer Phone Number +1 (248) 434-5508
Symptoms Fake error messages, fake system warnings, pop-up errors, hoax computer scan.
Distribution methods Compromised websites, rogue online pop-up ads, potentially unwanted applications.
Damage Loss of sensitive private information, monetary loss, identity theft, possible malware infections.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner.
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Technical support scam examples

"Critical Error IP Threat Detected", "Your Google Account Has Been Locked!", "Error Code: W9KA528V", "Subscription Renewed Successfully For 349$", and "Error Code: 0x80073b01" are just some examples of tech support scams that we have investigated recently.

The Internet is full of deceptive and malicious content. Various false claims and scare tactics are used to gain and subsequently abuse users' trust. However, regardless of what scams promise, warn, or demand – their sole purpose is to generate revenue at victims' expense.

How did I open a scam website?

Deceptive webpages can be force-opened the moment a site that uses rogue advertising networks is accessed. Additionally, the latter can generate redirects to the former whenever hosted content is clicked or otherwise interacted with (e.g., buttons, text input fields, links, ads, etc.).

Mistyping a website's URL can also result in a redirect (or a redirection chain leading) to a scam page. Spam browser notifications and intrusive advertisements promote online scams as well.

Adware installed on a device may display scam-promoting adverts or force-open webpages running them. Spam (e.g., emails, PMs/DMs, SMSes, forum posts, etc.) is another promoter of deceptive online content.

How to avoid visiting scam websites?

It is crucial to exercise caution while browsing since fake and malicious online content usually appears legitimate and harmless. Caution must be extended to incoming emails and other messages as well; attachments or links present in dubious mail must not be opened, as they can be harmful.

We advise against using websites that offer pirated software/media or other questionable services (e.g., Torrenting, illegal streaming or downloading, etc.) since these pages are typically monetized via rogue advertising networks. We recommend paying attention to URLs and entering them with care.

To avoid receiving unwanted browser notifications – do not permit suspicious webpages to deliver them (i.e., do not click "Allow", "Allow Notifications", etc.). Instead, ignore or deny notification delivery from such pages (i.e., press "Block", "Block Notifications", etc.).

Another recommendation is to download only from official/verified channels and be attentive when installing content (e.g., read terms, use "Custom/Advanced" settings, opt out of additional apps, extensions, tools, etc.) – to avoid allowing bundled/hazardous software to infiltrate the device.

If your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate all threats.

Text presented in "Operating System Blocked Due To Questionable Activity" scam pop-up:

Security Center

Questionable activity was discovered to be associated with your device.
Contact Microsoft Windows Tech Support as soon as possible.

Operating system has been blocked due to questionable activity.
Please Contact Windows Tech Support: +1 (248) 434-5508
If you think this computer lockup was by error, please inform Windows Tech Support about this issue.

[Exit] [Proceed]

The appearance of "Operating System Blocked Due To Questionable Activity" pop-up scam (GIF):

Appearance of Operating System Blocked Due To Questionable Activity scam (GIF)

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:
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Quick menu:

How to identify a pop-up scam?

Pop-up windows with various fake messages are a common type of lures cybercriminals use. They collect sensitive personal data, trick Internet users into calling fake tech support numbers, subscribe to useless online services, invest in shady cryptocurrency schemes, etc.

While in the majority of cases these pop-ups don't infect users' devices with malware, they can cause direct monetary loss or could result in identity theft.

Cybercriminals strive to create their rogue pop-up windows to look trustworthy, however, scams typically have the following characteristics:

  • Spelling mistakes and non-professional images - Closely inspect the information displayed in a pop-up. Spelling mistakes and unprofessional images could be a sign of a scam.
  • Sense of urgency - Countdown timer with a couple of minutes on it, asking you to enter your personal information or subscribe to some online service.
  • Statements that you won something - If you haven't participated in a lottery, online competition, etc., and you see a pop-up window stating that you won.
  • Computer or mobile device scan - A pop-up window that scans your device and informs of detected issues - is undoubtedly a scam; webpages cannot perform such actions.
  • Exclusivity - Pop-up windows stating that only you are given secret access to a financial scheme that can quickly make you rich.

Example of a pop-up scam:

Example of a pop-up scam

How do pop-up scams work?

Cybercriminals and deceptive marketers usually use various advertising networks, search engine poisoning techniques, and shady websites to generate traffic to their pop-ups. Users land on their online lures after clicking on fake download buttons, using a torrent website, or simply clicking on an Internet search engine result.

Based on users' location and device information, they are presented with a scam pop-up. Lures presented in such pop-ups range from get-rich-quick schemes to fake virus scans.

How to remove fake pop-ups?

In most cases, pop-up scams do not infect users' devices with malware. If you encountered a scam pop-up, simply closing it should be enough. In some cases scam, pop-ups may be hard to close; in such cases - close your Internet browser and restart it.

In extremely rare cases, you might need to reset your Internet browser. For this, use our instructions explaining how to reset Internet browser settings.

How to prevent fake pop-ups?

To prevent seeing pop-up scams, you should visit only reputable websites. Torrent, Crack, free online movie streaming, YouTube video download, and other websites of similar reputation commonly redirect Internet users to pop-up scams.

To minimize the risk of encountering pop-up scams, you should keep your Internet browsers up-to-date and use reputable anti-malware application. For this purpose, we recommend Combo Cleaner Antivirus for Windows.

What to do if you fell for a pop-up scam?

This depends on the type of scam that you fell for. Most commonly, pop-up scams try to trick users into sending money, giving away personal information, or giving access to one's device.

  • If you sent money to scammers: You should contact your financial institution and explain that you were scammed. If informed promptly, there's a chance to get your money back.
  • If you gave away your personal information: You should change your passwords and enable two-factor authentication in all online services that you use. Visit Federal Trade Commission to report identity theft and get personalized recovery steps.
  • If you let scammers connect to your device: You should scan your computer with reputable anti-malware (we recommend Combo Cleaner Antivirus for Windows) - cyber criminals could have planted trojans, keyloggers, and other malware, don't use your computer until removing possible threats.
  • Help other Internet users: report Internet scams to Federal Trade Commission.

Frequently Asked Questions (FAQ)

What is a pop-up scam?

Basically, pop-up scams are deceptive messages that trick users into performing specific actions. Victims can be enticed/scared into calling fake support lines, allowing cyber criminals to access their devices remotely, making monetary transactions, disclosing private information, downloading/installing software, purchasing products, subscribing to services, and so forth.

What is the purpose of a pop-up scam?

The goal of pop-up scams is to generate revenue for their designers. Cyber criminals predominantly profit by obtaining funds through deception, abusing or selling sensitive information, promoting content, and spreading malware.

Why do I encounter fake pop-ups?

Pop-up scams are promoted on deceptive webpages, which are seldom accessed intentionally. Most visitors enter them via redirects generated by sites utilizing rogue advertising networks, misspelled URLs, intrusive ads, spam browser notifications, or installed adware.

I cannot exit a scam page, how do I close it?

If you cannot exit a scam page, end the browser's process using Task Manager. Note that when the browser is reaccessed, the previous browsing session must not be restored – as that would reopen the deceptive webpage.

I have allowed cyber criminals to remotely access my computer, what should I do?

If you have permitted cyber criminals to access your device remotely – first, disconnect it from the Internet. Second, remove the remote access software that the criminals used (e.g., UltraViewer, TeamViewer, AnyDesk, etc.). Last, run a complete system scan with an anti-virus and eliminate all detected threats.

I have provided my personal information when tricked by a pop-up scam, what should I do?

If you have provided your log-in credentials – change the passwords of all possibly exposed accounts and inform their official support without delay. However, if the disclosed information was of a different personal nature (e.g., ID card details, passport photos/scans, credit card numbers, etc.) – immediately contact relevant authorities.

Will Combo Cleaner protect me from pop-up scams and the malware they proliferate?

Combo Cleaner is designed to detect and remove all manner of threats. It can scan visited sites for deceptive/malicious content. Hence, should you access such a webpage – you will be immediately warned, and further access to it will be blocked. Combo Cleaner is also capable of detecting and eliminating nearly all known malware infections. Keep in mind that performing a complete system scan is paramount since sophisticated malicious programs tend to hide 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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