Removal instructions for Lurk ransomware

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

Lurk ransomware removal instructions

What is Lurk?

Lurk is yet another ransomware-type infection discovered by malware researcher, Petrovic. After successful infiltration, Lurk encrypts most stored files and renames them using the following pattern: "[random_string].original_extension.lurk". For example, "1.jpg" file might be renamed to a filename such as "9iS14.jpg.lurk". Encrypted data immediately becomes unusable. After successful encryption, Lurk generates a text file called "how to recover.txt" and stores it on the desktop.

At time of research, Lurk's new text file contained only random characters, when in fact this file should contain decryption instructions. Therefore, it is safe to assume that this malware is still in development and cyber criminals are merely testing its capabilities. It is currently unknown how to contact Lurk's developers and what they want, since no information is provided. In any case, there is a high probability that this ransomware will be updated and the text file will then provide more information. Cyber criminals typically use text files to deliver ransom-demand messages. These state that files can only be restored using a unique decryption key/tool, which victims must purchase. The cost of decryption typically fluctuates between $500 and $1500, and victims are asked to submit payments using various cryptocurrencies (Bitcoins, Ethereum, Monero, DASH, and similar). If your computer ever becomes infected with ransom-demand malware, you should never agree to pay. Ransomware developers often ignore victims once payments are submitted. In this way, victims are scammed and paying gives no positive result. Unfortunately, there are no tools capable of cracking Lurk's encryption and restoring data free of charge. 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:

Lurk decrypt instructions

Lurk shares many similarities with Darus, 1BTC, HYDRA, and hundreds of other ransomware-type infections. Most compromise data so that developers can blackmail victims by offering paid recovery of their files. The only major differences are usually size of ransom and type of encryption algorithm used. Unfortunately, encryptions are typically performed using RSA, AES, and other high-end cryptographies that generate unique decryption keys individually for each victim. Therefore, unless the virus is not fully developed or has bugs/flaws, restoring data without developers' involvement is impossible. Ransomware infections present a strong case for maintaining regular backups, however, store them on a remote server (e.g., Cloud) or an unplugged storage device (external hard drive, Flash drive or similar), since locally stored backups will be compromised together with regular data. Furthermore, we strongly advise that you have multiple backup copies stored in different locations, since there is always a chance that servers/hardware can be damaged.

How did ransomware infect my computer?

The way developers proliferate Lurk is currently unknown, however, ransomware is typically proliferated using spam email campaigns, unofficial software download sources, fake software updaters and 'cracks', and trojans. Spam campaigns are used to send hundreds of thousands of deceptive emails containing malicious attachments and messages encouraging recipients to open them. Attachments are usually presented as 'important documents' (invoices, bills, receipts, and similar). In this way, criminals attempt to give the impression of legitimacy and increase the chance of tricking recipients. Unofficial software download sources (freeware download websites, Peer-to-Peer [P2P] networks, free file hosting sites, and similar) are used to present malicious executables as legitimate/genuine applications. Criminals use this technique to trick users into manual download/installation of malware. Fake software updaters infect systems by exploiting outdated software bugs/flaws or simply downloading installing malware rather than the promised updates. Fake cracking tools also have similar behavior - they infect computers rather than activating paid software free of charge. Finally, trojans infiltrate computers to inject additional malware (thereby causing chain infections). In summary, the main reasons for computer infections are poor knowledge of these threats and careless behavior.

Threat Summary:
Name Lurk virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .lurk (this ransomware also changes each filename to a random string).
Ransom Demanding Message how to remove.txt (at the time of research this file contained random characters).
Detection Names Avast (Win32:Trojan-gen), BitDefender (Trojan.GenericKD.41478292), ESET-NOD32 (Win32/Encore.A), Kaspersky (HEUR:Trojan-Ransom.Win32.Encoder.gen), Full List Of Detections (VirusTotal)
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Additional Information This ransomware is still in development and being tested, however, there is a significant possibility that it will eventually be updated and proper ransom-demands will be made.
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.
Removal

To eliminate Lurk 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?

To prevent this situation, be extremely cautious during the download/installation/update processes, and when browsing the Internet in general. Your programs should be downloaded from official sources only, preferably using direct download links. Third party downloaders/installers often include rogue applications, and thus these tools should never be used. Similar rules apply to software updates. 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 a cyber crime and the risk of infection is extremely high (most cracking tools are fake). Handle all received email attachments with care. Files/links sent from suspicious/unrecognizable email addresses should never be opened. The same applies to attachments that are irrelevant or do not concern you. Have a reputable anti-virus/anti-spyware suite installed and running, since these tools detect and remove viruses before they damage the system. The key to computer safety is caution. If your computer is already infected with Lurk, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Screenshot of files encrypted by Lurk (".lurk" extension):

Files encrypted by Lurk

Lurk ransomware removal:

Instant automatic removal of Lurk 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 Lurk 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 Lurk 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 Lurk 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 Lurk 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 Lurk 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 Lurk, 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 Lurk 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 Lurk ransomware:

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 virus and spyware activity level today:

Medium threat activity
Medium

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

QR Code
Lurk virus QR code
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