Jamper Ransomware

Also Known As: Jamper virus
Distribution: Low
Damage level: Severe

Jamper ransomware removal instructions

What is Jamper?

Jamper is a ransomware-type virus discovered by malware security researcher, Michael Gillespie. After successful infiltration, Jamper encrypts most stored data. Furthermore, this malware adds the ".jamper" appendix to each filename. I.e., "sample.jpg" is renamed to "sample.jpg.jamper". Once encryption is complete, Jamper generates a text file ("---README---.TXT") and places a copy in every existing folder. Updated variants of this ransomware use ".jumper" extension for encrypted files.

As with most ransomware, Jamper's text file contains a message informing victims that data is encrypted and can only be restored using a decryption tool, which victims must purchase. Unfortunately, this is mostly accurate. It is currently unconfirmed whether Jamper uses symmetric or asymmetric cryptography. In any case, a unique decryption key is generated for each victim. Restoring files without these keys is impossible. Cyber criminals store them on a remote server and make ransom demands - to receive a decryption key (or rather a tool with the key embedded within) and recover data, each victim must pay a ransom. The cost is not specified - all payment details are provided via email, however, ransomware developers usually demand $500-1500 in Bitcoins or another cryptocurrency. Furthermore, these people cannot be trusted. Whatever the cost, you should never agree to pay. Research shows that cyber criminals often ignore victims once payments are submitted. Therefore, paying typically gives no positive result and users are simply scammed. Unfortunately, there are no tools capable of cracking Jamper encryption and restoring data free of charge and, therefore, the only solution is to restore everything from a backup.

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

Jamper decrypt instructions

There are dozens of ransomware-type viruses similar to Jamper. The list of examples includes (but is not limited to) GILETTE, Yatron, Dy8wud, Promock, and Target777. Although these viruses are developed by different cyber criminals, their behavior is virtually identical - all compromise data and demand ransom payments. In most cases, cost of decryption and type of cryptography used are the only major differences. Unfortunately, these viruses typically employ algorithms such as RSA, AES, and others that generate unique decryption keys. Thus, restoring data without the involvement of developers (contacting these people is not recommended) is impossible unless the malware is still in development or has certain bugs/flaws. Ransomware is one of the main reasons why you should maintain regular data backups. Bear in mind, however, that backups should not be stored locally. You should use a remote server (e.g., Cloud) or unplugged storage devices. Locally stored backups are encrypted together with regular data.

Jamper ransomware technical analysis:

  • Detection names: Avast (Win32:Malware-gen), BitDefender (Gen:Variant.Jacard.149278), Kaspersky (HEUR:Trojan.Win32.Mucc.gen), ESET-NOD32 (a variant of Win32/Filecoder.Buhtrap.D)
  • Full list of antivirus detections: VirusTotal
  • Executable file name: DEFENDER.EXE
  • Sample first submitted: 2019-03-20 (created 2019-03-14)

How did ransomware infect my computer?

It is currently unknown exactly how developers proliferate Jamper, however, in most cases, ransomware developers use the following tools/methods: trojans, fake software updaters/cracks, unofficial download sources, and spam email campaigns. Trojans are essentially malicious applications designed to infiltrate computers and inject additional malware. Fake updaters infect systems in two ways: 1) by exploiting outdated software bugs/flaws or; 2) downloading and installing malware rather than the promised updates. The idea behind cracking tools is to activate paid software free of charge, however, criminals also use them to proliferate viruses, and thus users often end up infecting their computers rather than gaining access to paid features. Cyber criminals also proliferate malware using third party software download sources. They present malicious applications/executables as legitimate software, thereby tricking users into downloading and installing malware. Cyber criminals use spam email campaigns to proliferate malicious attachments (MS Office documents, PDFs, executables, etc.) together with messages encouraging recipients to open them, however, doing so results in various system infections. In most cases, the main reasons for computer infections are poor knowledge of these threats and careless behavior.

Threat Summary:
Name Jamper virus
Threat Type Ransomware, Crypto Virus, Files locker
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 Jamper virus our malware researchers recommend scanning your computer with Spyhunter.
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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?

The key to computer safety is caution. Therefore, to prevent computer infections, be very cautious when browsing the internet and downloading/installing/updating software. Download applications from official sources only. Third party downloaders/installers often include rogue apps, and thus these tools should never be used. Keep installed applications and operating systems up-to-date, however, use only implemented functions or tools provided by the official developer. Never attempt to crack installed applications, since software piracy is considered a cyber crime and the risk of infections is extremely high. Have a legitimate anti-virus/anti-spyware suite installed and running - these tools can protect the system by detecting and removing viruses before they do any harm. If your computer is already infected with Jamper, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Indication of infection (when the executable of this ransomware is launched, the following message is displayed):

jamper indication of infection

Text presented in Jamper ransomware text file ("---README---.TXT"):

All your important files are encrypted
There is only one way to get your files back: contact with us, pay, and get decryptor software.
We accept Bitcoin
You have Your personal identifier, write it in letter when contact with us.
Also you can decrypt 1 file for test, its guarantee what we can decrypt your files.
Do not rename encrypted files.
Do not try to decrypt using third party software, it may cause permanent data loss.
For decrypt your data write to email
Contact information:

Screenshot of files encrypted by Jamper (".jamper" extension):

Files encrypted by Jamper

Jamper ransomware removal:

Instant automatic removal of Jamper 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 Jamper 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 Jamper 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 Jamper 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 Jamper 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 Jamper 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 Jamper, 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 Jamper ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the 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 is more information on how to get this update and add an 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 Jamper ransomware: