Avoid downloading fake Flash updates from mainsourceofupdate.best

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

What is mainsourceofupdate[.]best?

mainsourceofupdate[.]best is a deceptive/scam web page, which claims that the visitor's Adobe Flash Player is outdated. It also endorses a fake Flash updater. These rogue updaters are used to proliferate a wide variety of untrustworthy and malicious content.

Few users access mainsourceofupdate[.]best intentionally, since most are redirected to this site by intrusive advertisements or Potentially Unwanted Applications (PUAs) already infiltrated into the system.

mainsourceofupdate[.]best scam

Visitors to mainsourceofupdate[.]best first see a pop-up window informing them that the Adobe Flash Player supposedly needs to be updated. After this pop-up is closed, the site displays another web page, which informs users that Adobe Flash Player is an essential browser plug-in.

Flash Player enables users to view content ranging from videos to animation, and is also necessary to play high-quality audio and certain online games. It states that, since this plug-in missing the latest security updates (i.e., the software is outdated), it has been blocked and is no longer operational.

To continue using Adobe Flash Player, mainsourceofupdate[.]best recommends updating it. This web page has a pop-up window in the bottom right corner. The text presented within this window urges users to continue watching (it does not specify what), since Flash Player requires the latest updates.

The page then shows yet another pop-up, which repeats the general message. If users are tricked by mainsourceofupdate[.]best, they will download/install a fake updater used to proliferate unwanted and malicious content (e.g. fake Mac cleaners/optimizers, browser hijackers, adware, trojans and so on).

As well as generating redirects to deceptive/scam, untrustworthy and malicious web pages, PUAs have other dangerous capabilities. PUAs often seem legitimate and tempt users to install with offers of "useful" features, which are usually nonoperational.

Unwanted apps such as fake system cleaners/optimizers often require activation to perform their advertised functions, however, despite being activated (i.e., purchases made), they remain nonfunctional. Adware-type applications run intrusive advertisement campaigns, diminishing the browsing experience and delivering harmful ads.

Browser hijackers make unauthorized changes to browsers and limit/deny access to their settings. PUAs commonly have data tracking capabilities. They record users' browsing activity (browsing and search engine histories) and gather personal information (IP addresses, geolocations and other details).

This private data can then shared with third parties (potentially, cyber criminals) intent on misusing it for profit. To summarize, PUAs can cause browser/system infiltration and infections, and lead to financial loss, serious privacy issues and even identity theft.

To ensure device integrity and user safety, remove all suspicious applications and browser extensions/plug-ins immediately upon detection.

Threat Summary:
Name mainsourceofupdate.best pop-up
Threat Type Phishing, Scam, Mac malware, Mac virus.
Fake Claim Site claims that visitors' Adobe Flash Player is outdated.
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)
Serving IP Address (mainsourceofupdate.best)
Promoted Unwanted Application This website promotes fake Flash Player 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.
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mainsiteofupdatenow[.]bestcentersourceoffreeupgrade[.]best, and securedconection[.]com are some examples of other scam websites. They tend to use social engineering and scare tactics to trick users into performing specific actions. For example, deceptive pages can claim that a crucial piece of software is outdated and then suggest updates.

They can also warn visitors that their devices are at risk/infected and offer applications for the removal of the nonexistent threats/issues. These are just some ways in which these sites encourage users into downloading/installing/purchasing untrustworthy or malicious content, revealing personal and/or banking information, and so on.

You are strongly advised against trusting web pages that "detect" any device threats or issues, make ludicrous offers, claim that visitors have won 'amazing' prizes, or similar.

How did potentially unwanted applications install on my computer?

Fake updaters can be the source of PUAs, however, these apps can also be installed together with other normal products. This deceptive marketing method of pre-packing regular software with unwanted or malicious content is called "bundling".

Rushing download/installation processes (e.g. ignoring terms, skipping steps, using pre-set options, etc.) increases the risk of inadvertently allowing bundled content onto devices, thereby endangering them with potential infiltration and infections. Some PUAs have "official" download pages.

When clicked, intrusive advertisements can execute scripts designed to download/install PUAs without users' consent.

How to avoid installation of potentially unwanted applications

You are strongly advised to research all content, prior to downloading/installing. Use only official and verified download channels. Do not use untrustworthy sources such as Peer-to-Peer sharing networks (BitTorrent, eMule, Gnutella, etc.), unofficial and free file-hosting websites, third party downloaders and similar - these are far more likely to offer deceptive and/or bundled products.

Software should be updated with tools/functions provided by legitimate developers. Third party updaters are high-risk and should be avoided. When downloading/installing, read the terms, explore all possible options, use the "Custom/Advanced" settings and opt-out of additional apps, tools, features, etc.

Intrusive ads usually seem normal and harmless, however, they redirect to dubious sites (e.g. gambling, pornography, adult-dating and others).

If you encounter ads/redirects of this kind, check the system 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.

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

Appearance of mainsourceofupdate[.]best scam (GIF)

Text presented in the initial pop-up window:

Update to the latest version of Flash Player. Your current Adobe Flash Player version is out of date.

Screenshot of the second page displayed by mainsourceofupdate[.]best:

mainsourceofupdate[.]best scam second page

Text presented in the background of this page:

Latest version of Flash Player is required to encode and/or decode (Play) audio files in high quality. - Click here to update for latest version.
Software update

Adobe Flash Player
Install the latest update
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.

To continue using “Adobe Flash Player", download an updated version.
Update Download Flash...

Text presented in the pop-up displayed on this page:

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

Screenshot of another pop-up displayed by mainsourceofupdate[.]best:

mainsourceofupdate[.]best scam third page

Text presented in this pop-up:

“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 you download an update from Adobe.Update Download Flash...

Screenshot of the fake Adobe Flash Player installer promoted via this scam website:

Rogue installer promoted via mainsourceofupdate.best pop-up scam

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.

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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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