PClock4 virus, also known as PClock SysGop ransomware, is the latest iteration of the PClock ransomware family.
PClock ransomware virus has been around for quite some time. Previous infection campaigns were using the XOR algorithm to encrypt the user’s data. A previous PClock version of the ransomware family was also pretending to be Cryptolocker, relying on the famous ransomware’s name and fame. This old infection was reported to ask for 0.5 Bitcoin in exchange for file decryption. Let’s see what has been changed in PClock4 ransomware virus, in the table below:
Threat Summary
Name |
PClock4 |
Type | ScreenLock Ransomware |
Short Description | PClock4, also known as PClock SysGop, uses the RSA-2048 encryption algorithm and targets a total of 2630 file type extensions. Reportedly it demands a ransom of 0.6 – 1.6 Bitcoin. |
Symptoms | The victim’s files are encrypted. A screen locker function is embedded in the source code of PClock4 which gets in the way of any user activity on the targeted machine. A ransom message is displayed. For full text of the message, see the article. |
Distribution Method | Spam emails. |
Detection Tool |
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User Experience | Join our forum to Discuss PClock4. |
Data Recovery Tool | Windows Data Recovery by Stellar Phoenix Notice! This product scans your drive sectors to recover lost files and it may not recover 100% of the encrypted files, but only few of them, depending on the situation and whether or not you have reformatted your drive. |
Unfortunately, in October researchers reported that there was no longer a way to decrypt newer PClock variants without the original decryption key possessed by criminals. The free decrypter coded by Fabian Wosar got broken when the ransomware authors updated their code. However, there still may be a chance for you to obtain access to your encrypted data via using powerful data recovery software or via data back ups.
There is no guarantee software data recovery attempts will be successful but in some cases users have shared positive results in restoring data partially. You will find data recovery solutions at the end of this article, where you will also be instructed on how to remove PClock both manually and automatically.
PClock 4 Ransomware Distribution Method
PClock4 has been reported to spread mainly in spam email campaigns. Such campaigns tend to become more intensive during the winter holidays season when people are less aware of potential online infections. The ransomware’s payload may be hiding in attached files appearing to be sent by legal organizations. Here are two examples of subject lines of PClock4 spam campaign:
- PLEASE READ YOUR FAX T6931
- Criminal case against you
Researchers report that the malware is attached in WSF files which contain the payload dropper – Crimace Trojan.
More particularly,a RAR archive contains a WSF file. When users download and open the archive, and execute the WSF file, a JScript function is set to initiate a series of operations that download and run a malware known as Crimace, known to be detected as TrojanDownloader:JS/Crimace.A.
The Trojan is a malware downloader, that connects to an online server and downloads and runs other malware such as PClock4. Other malware can be distributed the same way, too.
Besides being sent out in aggressive spam and phishing campaigns, the ransomware may be distributed in exploit kit operations.
PClock4 Ransomware – Further Technical Analysis
By comparing screenshots of PClock4 previous campaigns and the latest one described here, we will see that not much has changed. In other words, the ransomware hasn’t evolved, or at least no big changes have been observed. Here is an example of the latest campaign, provided by Microsoft:
The ransomware has been detected by Microsoft as Ransom:Win32/WinPlock.B or WinPlock, and is more commonly referred to as PClock. The first infections of the crypto virus were observed in 2015.
Emsisoft security researcher Fabian Wosar was able to create a decrypter for the earlier versions that enabled users to decrypt their files for free. Unfortunately, this is not the case any longer, as cybercriminals updated their code in May 2015 and broke the decrypter. The only way for PClock victims was to restore encrypted data from backup files or by paying the ransom, which is never recommended as it doesn’t guarantee any success. After all, don’t forget you are dealing with cybercriminals.
Interestingly, despite being known for more than 2 years, PClock has remained an entry-level operation even in the PClock4 iteration. The ransomware still requires its victims to get in contact with the authors via email, which is an ancient tactic. The only change in PClock4 appears to be the number of files targeted for encryption – it has jumped from 100+ files types, to 2,630.
Remove PClock4 and Restore Encrypted Files
PClock4 can be removed manually – the first half of PClock4 removal manual below will guide you through the process but keep in mind at least some experience in malware removal is needed. If you don’t feel confident enough, please refer to the instructions for PClock4 automatic removal.
- Guide 1: How to Remove PClock4 from Windows.
- Guide 2: Get rid of PClock4 from Mac OS X.
- Guide 3: Remove PClock4 from Google Chrome.
- Guide 4: Erase PClock4 from Mozilla Firefox.
- Guide 5: Uninstall PClock4 from Microsoft Edge.
- Guide 6: Remove PClock4 from Safari.
- Guide 7: Eliminate PClock4 from Internet Explorer.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
How to Remove PClock4 from Windows.
Step 1: Boot Your PC In Safe Mode to isolate and remove PClock4





Step 2: Uninstall PClock4 and related software from Windows
Here is a method in few easy steps that should be able to uninstall most programs. No matter if you are using Windows 10, 8, 7, Vista or XP, those steps will get the job done. Dragging the program or its folder to the recycle bin can be a very bad decision. If you do that, bits and pieces of the program are left behind, and that can lead to unstable work of your PC, errors with the file type associations and other unpleasant activities. The proper way to get a program off your computer is to Uninstall it. To do that:



Step 3: Clean any registries, created by PClock4 on your computer.
The usually targeted registries of Windows machines are the following:
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
You can access them by opening the Windows registry editor and deleting any values, created by PClock4 there. This can happen by following the steps underneath:



Before starting "Step 4", please boot back into Normal mode, in case you are currently in Safe Mode.
This will enable you to install and use SpyHunter 5 successfully.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Get rid of PClock4 from Mac OS X.
Step 1: Uninstall PClock4 and remove related files and objects
1. Hit the ⇧+⌘+U keys to open Utilities. Another way is to click on “Go” and then click “Utilities”, like the image below shows:
- Go to Finder.
- In the search bar type the name of the app that you want to remove.
- Above the search bar change the two drop down menus to “System Files” and “Are Included” so that you can see all of the files associated with the application you want to remove. Bear in mind that some of the files may not be related to the app so be very careful which files you delete.
- If all of the files are related, hold the ⌘+A buttons to select them and then drive them to “Trash”.
In case you cannot remove PClock4 via Step 1 above:
In case you cannot find the virus files and objects in your Applications or other places we have shown above, you can manually look for them in the Libraries of your Mac. But before doing this, please read the disclaimer below:
You can repeat the same procedure with the following other Library directories:
→ ~/Library/LaunchAgents
/Library/LaunchDaemons
Tip: ~ is there on purpose, because it leads to more LaunchAgents.
Step 2: Scan for and remove PClock4 files from your Mac
When you are facing problems on your Mac as a result of unwanted scripts and programs such as PClock4, the recommended way of eliminating the threat is by using an anti-malware program. SpyHunter for Mac offers advanced security features along with other modules that will improve your Mac’s security and protect it in the future.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Remove PClock4 from Google Chrome.
Step 1: Start Google Chrome and open the drop menu
Step 2: Move the cursor over "Tools" and then from the extended menu choose "Extensions"
Step 3: From the opened "Extensions" menu locate the unwanted extension and click on its "Remove" button.
Step 4: After the extension is removed, restart Google Chrome by closing it from the red "X" button at the top right corner and start it again.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Erase PClock4 from Mozilla Firefox.
Step 1: Start Mozilla Firefox. Open the menu window
Step 2: Select the "Add-ons" icon from the menu.
Step 3: Select the unwanted extension and click "Remove"
Step 4: After the extension is removed, restart Mozilla Firefox by closing it from the red "X" button at the top right corner and start it again.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Uninstall PClock4 from Microsoft Edge.
Step 1: Start Edge browser.
Step 2: Open the drop menu by clicking on the icon at the top right corner.
Step 3: From the drop menu select "Extensions".
Step 4: Choose the suspected malicious extension you want to remove and then click on the gear icon.
Step 5: Remove the malicious extension by scrolling down and then clicking on Uninstall.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Remove PClock4 from Safari.
Step 1: Start the Safari app.
Step 2: After hovering your mouse cursor to the top of the screen, click on the Safari text to open its drop down menu.
Step 3: From the menu, click on "Preferences".
Step 4: After that, select the 'Extensions' Tab.
Step 5: Click once on the extension you want to remove.
Step 6: Click 'Uninstall'.
A pop-up window will appear asking for confirmation to uninstall the extension. Select 'Uninstall' again, and the PClock4 will be removed.
Windows Mac OS X Google Chrome Mozilla Firefox Microsoft Edge Safari Internet Explorer
Eliminate PClock4 from Internet Explorer.
Step 1: Start Internet Explorer.
Step 2: Click on the gear icon labeled 'Tools' to open the drop menu and select 'Manage Add-ons'
Step 3: In the 'Manage Add-ons' window.
Step 4: Select the extension you want to remove and then click 'Disable'. A pop-up window will appear to inform you that you are about to disable the selected extension, and some more add-ons might be disabled as well. Leave all the boxes checked, and click 'Disable'.
Step 5: After the unwanted extension has been removed, restart Internet Explorer by closing it from the red 'X' button located at the top right corner and start it again.