Jack Ransomware

Also Known As: Jack virus
Distribution: Moderate
Damage level: Severe

Jack ransomware removal instructions

What is Jack?

Jack is a high-risk ransomware that belongs to a family of ransomware infections called Dharma. This malware was firstly discovered by a cyber security researcher Jakub Kroustek. After successful infiltration, Jack encrypts most of stored data and appends filenames with ".jack" extension, alongside with victim's unique ID and developers' email addresses. Therefore, encrypted "sample.jpg" would be renamed to something like "sample.jpg.id-1E857D00.[lockhelp@qq.com].jack". In addition to encrypting data, Jack drops "RETURN FILES.txt" text file on victim's desktop and opens a pop-up window.

The created text file contains a short message simply stating that data is encrypted and that victims must contact cyber criminals via provided email address. Pop-up, on the other hand, provides a bit more information. It also states that files are encrypted and that victim must contact cyber criminals in order to restore it. However, the message also specifies that decryption requires a unique key, which is unfortunately true. It is stated that data is encrypted using RSA-1024 cryptography, which is asymmetric. If that is the case, each victim gets a unique decryption key (also known as private key) which is necessary to restore data. The problem is that victims cannot access their keys, since developers store them in a remote server. The message states that in order to receive one's key and restore data each victim has to pay a ransom. It is also noted that ransom must be paid within 7 days after the encryption, otherwise the key will be permanently deleted (overwritten by other peoples' keys). The exact price is not specified - all payment details are provided via email. Yet it is worth mentioning that size of ransom usually fluctuates between $500 and $1500, and crooks ask to submit payments using Bitcoin, Monero, Ethereum, or other cryptocurrencies. Cyber criminals also offer a decryption of one file (up to 1MB, non-archived) as a guarantee that recovery is impossible and that these persons can be trusted. However, users should know that cyber criminals often ignore victims, once payments are submitted. In other words, paying typically gives no positive result and users simply get scammed. Unluckily, Jack is an undecryptable ransomware, meaning that there are no tools capable of cracking its encryption and restoring data for free. The only thing victims can do is restore everything from a backup, if there is one created.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

Jack decrypt instructions

There are hundreds of ransomware-type infections that share similarities with Jack (e.g., SYSTEM FAILURE, Bufas, Qbtex, etc.) As with Jack, most of ransomware infections encrypt data so that developers could make ransom demands. The problem is that such infections typically employ cryptographies (e.g., RSA, AES, etc.) that generate unique decryption keys. Therefore, unless the ransomware is still in development and/or has certain bugs/flaws, restoring data manually (without developers interfering) is virtually impossible. Infections like Jack present a strong case for maintaining regular data backups. However, be sure to store them in a remote server, or either an unplugged storage device, since locally stored backups will probably be encrypted together with regular data. It is also advised to have multiple backup copies stored in different locations, just in case the used storage device/server is damaged.

How did ransomware infect my computer?

In order to proliferate ransomware infections developers often use trojans, fake software updaters/cracks, email spam campaigns, and third party software download sources. Trojans are essentially malicious applications that stealthily infiltrate computers and download/install additional malware. Fake updaters typically infect computers by exploiting outdated software's bugs/flaws or simply downloading and installing malware rather than actual updates. Fake cracks are also very similar to fake updaters. Instead of providing access to software's paid features, fake cracks inject malware into the system. Email spam campaigns are designed to deliver hundreds of thousands of emails consisting of malicious attachments (links/files) and deceptive messages encouraging users to open them. In order to create the impression of legitimacy and trick users into opening cyber criminals often present malicious attachments as some important documents (e.g., bills, invoices, receipts, etc.) Unofficial software download sources are also used in a similar manner. Crooks present malicious executables as legitimate software, thereby tricking users into downloading and installing malware manually.

Threat Summary:
Name Jack virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .jack (this ransomware also appends filenames with victim's unique ID and developers' email address)
Ransom Demanding Message Pop-up window, RETURN FILES.txt text file
Cyber Criminal Contact lockhelp@qq.com
Detection Names Avast (Win32:Trojan-gen), ESET-NOD32 (Win32/Filecoder.Crysis.P), Kaspersky (Trojan-Ransom.Win32.Foreign.oghu), McAfee (Artemis!734F9B50616F), Full List Of Detections (VirusTotal)
Symptoms Can't open files stored on your computer, previously functional files now have a different extension, for example my.docx.locked. A ransom demanding message is displayed on your desktop. Cyber criminals are asking to pay a ransom (usually in bitcoins) to unlock your files.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password stealing trojans and malware infections can be installed together with a ransomware infection.

To eliminate Jack virus our malware researchers recommend scanning your computer with Spyhunter.
▼ Download Spyhunter
Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

How to protect yourself from ransomware infections?

First of all, every user must realize that the main reasons for computer infections are reckless behavior and lack of knowledge. The key to its safety is caution. Therefore, paying close attention when browsing the Internet and downloading/installing/updating software is paramount. You should always handle all email attachments with care. If the received link/file is irrelevant and/or the sender looks suspicious/unrecognizable, then do not open anything. Desired software should be downloaded only from official sources (via direct download links) rather than using some third party download/installation tools, because they are often used to spread malware. Same goes for software updates. You should update installed applications and operating system only by using tools provided by the official developer or, even better, implemented update functions. Be aware that software piracy is considered a cyber crime and, as we've already mentioned, the risk of infections is extremely high. For this reason, you should never attempt to crack any installed applications. On top of all that, be sure to have a reputable anti-virus/anti-spyware suite installed and running at all times. Software of this type will help you to detect and eliminate malware before the system is harmed. If your computer is already infected with Jack, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Jack ransomware's pop-up window:

You can send us up to 1 file for free decryption. The total size of files must be less than 1Mb (non archived), and files should not contain valuable information. (databases,backups, large excel sheets, etc.)
When you make sure of decryption possibility transfer the money to our bitcoin wallet. As soon as we receive the money we will send you:
1. Decryption program.
2. Detailed instruction for decryption.
3. And individual keys for decrypting your files.
Do not rename encrypted files.
Do not try to decrypt your data using third party software, it may cause permanent data loss.
Decryption of your files with the help of third parties may cause increased price (they add their fee to our) or you can become a victim of a scam.

Screenshot of Jack's text file ("RETURN FILES.txt"):

Jack text file

Text presented within this file:

All your data is encrypted!
for return write to mail:

Screenshot of files encrypted by Jack (".jack" extension):

Files encrypted by Jack

Jack ransomware removal:

Instant automatic removal of Jack virus: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of Jack virus. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter 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 Spyhunter.

Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the Jack virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the Jack ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining Jack ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of Jack are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by Jack, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as Jack ransomware.

Note that Windows 10 Fall Creators Update includes "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default this feature automatically protects files stored in Documents, Pictures, Videos, Music, Favorites as well as Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here's more information on how to get this update and add additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove Jack ransomware: