Elimination of OSX/Linker malware

Also Known As: OSX/Linker malware
Type: Mac Virus
Distribution: Low
Damage level: Severe

How to remove "OSX/Linker" from Mac?

What is "OSX/Linker"?

OSX/Linker is a generic name for malware that exploits a zero-day MacOS Gatekeeper vulnerability to infect the system. Infections of this type are designed to use symbolic links (or 'symlinks') to bypass MacOS protection by accessing a Network File System (NFS) server and injecting malicious applications into the system (rather than downloading them directly from the Internet).

OSX/Linker scam

MacOS uses a technology called Gatekeeper, which checks each downloaded application and scans it for possible malware infections, however, applications loaded from a network (in this case, NFS server) are treated differently. Therefore, cyber criminals started misusing symlinks to access files stored in these networks. A symlink is essentially a file that contains a reference to another file/directory (so-called 'target'). It is essentially a shortcut, which contains path to a specific target and allows the user to access it indirectly. This is where cyber criminals take advantage. As mentioned above, MacOS treats applications loaded from a network differently. Therefore, cyber criminals use symlinks to access malicious files and inject them into the system. The symlinks are not categorized as malware, and thus malware scans are bypassed. Cyber criminals can use this technique to proliferate various malware types, including adware, browser hijackers, or even higher-risk infections such as trojans, cryptominers, and so on. Apple has been aware of this vulnerability since early 2019. Cybersecurity expert Filippo Cavallarin informed Apple about this flaw on February 22, 2019 and Apple responded that the vulnerability would be eliminated within 90 days. In fact, it remains and criminals continue to abuse this flaw. If you suspect the presence of any malware, immediately scan the system with a reputable anti-virus/anti-spyware suite (such as Combo Cleaner) and eliminate all detected threats.

Threat Summary:
Name OSX/Linker malware
Threat Type Trojan, Mac malware, Mac virus
Detection Names (Play.dmg) Avast (MacOS:Agent-FJ [Adw]), ESET-NOD32 (OSX/Linker.A), Kaspersky (HEUR:Trojan.OSX.Linker.a), Symantec (OSX.Trojan.Gen.2), Full List (VirusTotal)
Symptoms Your Mac becomes slower than normal, you see unwanted pop-up ads, you are redirected to dubious websites, you have noticed the presence of dubious applications.
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.
Removal

To eliminate OSX/Linker malware our malware researchers recommend scanning your computer with Combo Cleaner.
▼ Download Combo Cleaner
Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Combo Cleaner.

Criminals often abuse various operating system and software vulnerabilities to infect computers, however, most of these bugs/flaws are considered "zero-day", indicating that OS/software developers are aware and it is only a matter of time before they are eliminated. Furthermore, eliminating significant vulnerabilities is a priority for developers who often release so-called "patches" within few days or even hours after discovery. Cyber criminals are thus rarely able to abuse these bugs/flaws for long, and generally only happens when the operating system or software is no longer supported by the developer.

How did potentially unwanted applications install on my computer?

OSX/Linker malware symlinks are distributed in various formats (current known samples used the .app, .dmg and .iso formats). Cyber criminals proliferate these apps/disk images by presenting them as legitimate software installers, updaters, or files. One of the analyzed samples was a .app application, which had a MacOS directory icon. In this way, unsuspecting users are tricked into running an app whilst believing that they are simply opening a downloaded directory. Criminals also use disk images files by presenting them as Adobe Flash Player updaters. These fake updaters are often promoted on scam websites that display fake pop-ups/error messages claiming that users' Flash Players are outdated and encouraging them to download updates. One of these disk images was signed using an Apple Developer ID that belongs to the criminals who developed SurfBuyer adware. Therefore, it is very likely that these people abuse a OSX/Linker vulnerability to spread SurfBuyer adware or newer variants (such as MyCouponsmart, MyShopcoupon, or others). These apps/disk images might also be distributed using unofficial software download sources, such as Peer-to-Peer (P2P) networks, free file hosting websites, freeware download websites, and similar. Criminals present malicious executables as legitimate software, thereby tricking users into manual download/installation of malware.

How to avoid installation of potentially unwanted applications?

To prevent these computer infections, be very cautious when browsing the Internet and downloading/updating/installing software. Download software from official sources only, using direct download links (third party downloaders/installers often include rogue apps, and thus such tools should not be used). Similar rules apply to software updates. Keep installed applications/operating systems up-to-date, however, only through implemented functions or tools provided by the official developer. Have a reputable anti-virus/anti-spyware suite installed and running - these tools detect and eliminate malware before it harms the system. If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for macOS to automatically eliminate them.

Deceptive installer promoting MyCouponsmart adware:

MyCouponsmart adware promoting installer

Instant automatic removal of OSX/Linker malware: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of OSX/Linker 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. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Combo Cleaner.

Quick menu:

Video showing how to remove adware and browser hijackers from a Mac computer:

Potentially unwanted applications removal:

Remove potentially unwanted applications from your "Applications" folder:

mac browser hijacker removal from applications folder

Click the Finder icon. In the Finder window, select "Applications". In the applications folder, look for "MPlayerX","NicePlayer", or other suspicious applications and drag them to the Trash. After removing the potentially unwanted application(s) that cause online ads, scan your Mac for any remaining unwanted components.

Remove osx/linker malware related files and folders:

Finder go to folder command

Click the Finder icon, from the menu bar. Choose Go, and click Go to Folder...

step1Check for adware-generated files in the /Library/LaunchAgents folder:

removing adware from launch agents folder step 1

In the Go to Folder... bar, type: /Library/LaunchAgents

removing adware from launch agents folder step 2
In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

step2Check for adware generated files in the /Library/Application Support folder:

removing adware from application support folder step 1

In the Go to Folder... bar, type: /Library/Application Support

removing adware from application support folder step 2
In the “Application Support” folder, look for any recently-added suspicious folders. For example, “MplayerX” or “NicePlayer”, and move these folders to the Trash.

step3Check for adware-generated files in the ~/Library/LaunchAgents folder:

removing adware from ~launch agents folder step 1


In the Go to Folder bar, type: ~/Library/LaunchAgents

removing adware from ~launch agents folder step 2

In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

step4Check for adware-generated files in the /Library/LaunchDaemons folder:

removing adware from launch daemons folder step 1
In the Go to Folder... bar, type: /Library/LaunchDaemons

removing adware from launch daemons folder step 2
In the “LaunchDaemons” folder, look for recently-added suspicious files. For example “com.aoudad.net-preferences.plist”, “com.myppes.net-preferences.plist”, "com.kuklorest.net-preferences.plist”, “com.avickUpd.plist”, etc., and move them to the Trash.

step 5 Scan your Mac with Combo Cleaner:

If you have followed all the steps in the correct order you Mac should be clean of infections. To be sure your system is not infected run a scan with Combo Cleaner Antivirus. Download it HERE. After downloading the file double click combocleaner.dmg installer, in the opened window drag and drop Combo Cleaner icon on top of the Applications icon. Now open your launchpad and click on the Combo Cleaner icon. Wait until Combo Cleaner updates it's virus definition database and click "Start Combo Scan" button.

scan-with-combo-cleaner-1

Combo Cleaner will scan your Mac for malware infections. If the antivirus scan displays "no threats found" - this means that you can continue with the removal guide, otherwise it's recommended to remove any found infections before continuing.

scan-with-combo-cleaner-2

After removing files and folders generated by the adware, continue to remove rogue extensions from your Internet browsers.

OSX/Linker malware removal from Internet browsers:

safari browser iconRemove malicious extensions from Safari:

Remove osx/linker malware related Safari extensions:

safari browser preferences

Open Safari browser, from the menu bar, select "Safari" and click "Preferences...".

safari extensions window

In the preferences window, select "Extensions" and look for any recently-installed suspicious extensions. When located, click the "Uninstall" button next to it/them. Note that you can safely uninstall all extensions from your Safari browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Safari.

firefox browser iconRemove malicious plug-ins from Mozilla Firefox:

Remove osx/linker malware related Mozilla Firefox add-ons:

accessing mozilla firefox add-ons

Open your Mozilla Firefox browser. At the top right corner of the screen, click the "Open Menu" (three horizontal lines) button. From the opened menu, choose "Add-ons".

removing malicious add-ons from mozilla firefox

Choose the "Extensions" tab and look for any recently-installed suspicious add-ons. When located, click the "Remove" button next to it/them. Note that you can safely uninstall all extensions from your Mozilla Firefox browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Mozilla Firefox.

chrome-browser-iconRemove malicious extensions from Google Chrome:

Remove osx/linker malware related Google Chrome add-ons:

removing malicious google chrome extensions step 1

Open Google Chrome and click the "Chrome menu" (three horizontal lines) button located in the top-right corner of the browser window. From the drop-down menu, choose "More Tools" and select "Extensions".

removing malicious Google Chrome extensions step 2

In the "Extensions" window, look for any recently-installed suspicious add-ons. When located, click the "Trash" button next to it/them. Note that you can safely uninstall all extensions from your Google Chrome browser - none are crucial for normal browser operation.

  • If you continue to have problems with browser redirects and unwanted advertisements - Reset Google Chrome.

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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Removal Instructions in other languages
Malware activity

Global virus and spyware activity level today:

Medium threat activity
Medium

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

QR Code
OSX/Linker malware QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of OSX/Linker malware on your mobile device.
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Platform: macOS

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Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Combo Cleaner.