Avoid downloading fake software updates from mainsiteofupgradenow.best

Also Known As: mainsiteofupgradenow.best pop-up
Type: Mac Virus
Damage level: Medium

What is mainsiteofupgradenow[.]best?

mainsiteofupgradenow[.]best is a scam website and practically identical to mainsourceofupdate[.]best. It is designed to endorse a fake Adobe Flash Player updater. Visitors to this site are warned that the aforementioned plug-in is outdated and recommends an update.

Content promoted on deceptive webpages is often untrustworthy and malicious. Rogue updaters are commonly used to spread Potentially Unwanted Applications (PUAs) such as fake system cleaners and optimizers, browser hijackers, adware, and even malware.

Most users enter mainsiteofupgradenow[.]best unintentionally, since they are redirected by intrusive advertisements or PUAs already infiltrated into the device.

mainsiteofupgradenow[.]best scam

When entered, mainsiteofupgradenow[.]best displays a pop-up window with text claiming that visitors' Adobe Flash Player is outdated. It states that, due to the Flash Player lacking the latest security updates, it can no longer be used. This window has two buttons ("Update" and "Download Flash"), which if clicked initiate download of the fraudulent updater.

Another pop-up is presented in the bottom-right area of the web page. It urges users to install the latest version of Adobe Flash Player to continue watching content. The background page of mainsiteofupgradenow[.]best states that the updates are necessary to improve Flash Player's performance.

The software is an essential browser plug-in, which enables users to play various mediums (e.g. videos, animations, audio, online games, etc.). The deceptive website then reiterates that, as Adobe Flash Player is out-of-date, it has been blocked and recommends that the plug-in be updated so that it can be continued to be used.

This web page also has several identical buttons, which lead to the download of the fake updates. The updater will not install the promised updates - instead, it will allow unwanted and/or malicious software onto the system.

Potentially Unwanted Applications (PUAs) can force-open mainsiteofupgradenow[.]best, however, these apps redirect to normal sites as well as deceptive/scam sites. They can open various sale-oriented, untrustworthy, rogue, compromised and malicious sites. 'PUA' is a term that encompasses various unwanted products, which possess different capabilities.

Rogue system cleaners/optimizers are also classified as such. These typically require activation to perform their advertised functions (e.g. to remove threats, issues, unnecessary files, etc.), yet after activation (via purchase), they remain nonoperational. Adware is another type of PUA, which operates by delivering intrusive advertisements.

The delivered ads diminish the browsing experience, generate redirects to dangerous web pages and stealthily download/install content. PUAs categorized as browser hijackers make unauthorized changes to browsers and limit/deny access to settings. Most unwanted applications (regardless of specific capabilities) can track data.

They monitor users' browsing activity (browsing and search engine histories) and collect personal information (IP addresses, geolocations and other details). This sensitive data can then be shared with third parties (often, cyber criminals) intent on misusing it for profit.

To summarize, PUAs can cause browser/system infiltration and infections, lead to financial loss, serious privacy issues and even identity theft. Therefore, you are strongly advised to remove all suspicious applications and/or browser extensions immediately upon detection.

Threat Summary:
Name mainsiteofupgradenow.best pop-up
Threat Type Phishing, Scam, Mac malware, Mac virus.
Fake Claim Website claims the visitors' Flash Players are out of date.
Detection Names (fake updater)
Avast (Other:Malware-gen [Trj]), BitDefender (Adware.MAC.Bundlore.DPS), ClamAV (Osx.Trojan.SHLayer-6992220-1), Kaspersky (HEUR:Trojan-Downloader.OSX.Shlayer.a), Full List (VirusTotal)
Promoted Unwanted Application Website promotes fake software updaters.
Symptoms Your Mac becomes slower than normal, you see unwanted pop-up ads, you are redirected to dubious websites.
Distribution methods Deceptive pop-up ads, free software installers (bundling), fake Flash Player installers, torrent file downloads.
Damage Internet browser tracking (potential privacy issues), display of unwanted ads, redirects to dubious websites, loss of private information.
Malware Removal (Mac)

To eliminate possible malware infections, scan your Mac with legitimate antivirus software. Our security researchers recommend using Combo Cleaner.
▼ Download Combo Cleaner for Mac
To use full-featured product, you have to purchase a license for Combo Cleaner. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

The internet is rife with deceptive/scam websites and they tend to use various techniques to achieve their goals. Primarily, social engineering and scare tactics are employed to encourage users' into performing specific actions.

For example, these pages can claim that a crucial piece of software is outdated, the device has been infected, the visitors have won 'amazing' prizes, and so on. The purpose might be to trick users into downloading/installing or purchasing dubious/malicious content, revealing their personal and banking information, etc.

Note that mainsiteofupdatenow[.]best, centersourceoffreeupgrade[.]best, and mainsourceofupdate[.]best are a few examples of scams similar to mainsiteofupgradenow[.]best. You are expressly advised against visiting or trusting such sites.

How did potentially unwanted applications install on my computer?

PUAs can infiltrate devices disguised as different products (e.g. software updaters), however, they can also be downloaded/installed together with normal content. This deceptive marketing method of pre-packing regular programs with unwanted or malicious software is called "bundling".

Rushing download/installation processes (e.g. ignoring terms, skipping steps, etc.) increases the risk of potential system infiltration and infections. Some PUAs have "official" promotional web pages, where then are often endorsed as "useful" and "free". When clicked, intrusive advertisements can execute scripts to download/install PUAs without users' consent.

How to avoid installation of potentially unwanted applications

It is important to research all content, prior to downloading/installing. Use only official and verified download sources. The same applies to software activation and update - this should only be done with tools/functions provided by legitimate developers.

Untrustworthy download channels such as P2P sharing networks (BitTorrent, Gnutella, eMule, etc.), free file-hosting websites and other third party downloaders are more likely to offer deceptive and/or bundled products, and should not be used.

When downloading/installing, read the terms, explore all possible options, use the "Custom/Advanced" settings and opt-out of additional apps, tools, features and so on. Intrusive ads usually seem normal and innocuous, however, they can redirect to highly dubious sites (e.g. gambling, pornography, adult-dating, etc.).

If you encounter these advertisements/redirects, inspect the device and immediately remove all dubious applications and/or browser extensions/plug-ins. If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for macOS to automatically eliminate them.

Text presented in the mainsiteofupgradenow[.]best center pop-up window:

Software update

"Adobe Flash Player" is out-of-date

The version of this plug-in on your computer doesn't include the latest security updates. Flash cannot be used until yu download an update from Adobe.

Update Download Flash...

Screenshot of mainsiteofupgradenow[.]best background page:

mainsiteofupgradenow[.]best scam background page

Text presented in the background page:

Software update

Update your Adobe Flash Player

Install the latest Flash Player for better performances.

Update Now

"Adobe Flash Player" is an essential plugin for your browser that allows you to view everything from video to games and animation on the web. The version of “Adobe Flash Player" on your system does not include the latest security updates and has been blocked.

The version of this plug-in on your computer doesn't include the latest security updates. Flash cannot be used until you download an update from Adobe.

Click "Download Flash"

Install updates and enjoy performances

Text presented in the bottom-right pop-up:

Flash Player Update REQUIRED

Install latest version of Adobe Flash Player in order to continue watching.


Appearance of mainsiteofupgradenow[.]best scam (GIF):

Appearance of mainsiteofupgradenow[.]best scam (GIF)

Screenshot of the fake Flash Player updater:

mainsiteofupgradenow[.]best scam fake updater installer

Instant automatic Mac 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 Mac malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner for Mac 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. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

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 macOS.

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 macOS) - 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.

▼ Show Discussion

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.

Our malware removal guides are free. However, if you want to support us you can send us a donation.

About PCrisk

PCrisk is a cyber security portal, informing Internet users about the latest digital threats. Our content is provided by security experts and professional malware researchers. Read more about us.

Malware activity

Global malware activity level today:

Medium threat activity

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

QR Code
mainsiteofupgradenow.best pop-up QR code
Scan this QR code to have an easy access removal guide of mainsiteofupgradenow.best pop-up on your mobile device.
We Recommend:

Get rid of Mac malware infections today:

Download Combo Cleaner for Mac

Platform: macOS

Editors' Rating for Combo Cleaner:
Editors ratingOutstanding!

[Back to Top]

To use full-featured product, you have to purchase a license for Combo Cleaner. Limited seven days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.