Avoid data loss caused by Derp ransomware

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

Derp ransomware removal instructions

What is Derp?

Derp is malicious software categorized as ransomware. Derp is a part of a ransomware family called Djvu. Like most programs of this type, it encrypts files so that victims cannot access or use them unless they pay ransoms to cyber criminals. Furthermore, Derp renames all encrypted files by changing their extensions to ".derp". For example, "1.jpg" becomes "1.jpg.derp". It also creates a text files named "_readme.txt" and stores a copy in every folder that contains encrypted data.

The "_readme.txt" file contains a ransom message with instructions about how to obtain a decryption tool and key - victims must contact Derp's developers by sending an email to gorentos@bitmessage.ch or gerentosrestore@firemail.cc. The message must contain the appointed personal ID. Victims are permitted to send one encrypted file, which Derp developers should decrypt free of charge. To purchase decryption tools at a discount price ($490), victims are encouraged to contact cyber criminals within 72 hours of encryption. If not, they must pay the full cost of $980. It is made clear that it is impossible to decrypt files without purchasing decryption tools held only by the cyber criminals who developed Derp. Unfortunately, this information is accurate. Like most programs of this type, Derp encrypts data using a strong encryption algorithm. Therefore, the only way to decrypt files is to use the correct tool. Do not pay cyber criminals for this tool, since there is a high probability that they will not send anything. In many cases, people trust and pay ransomware developers, and are then scammed. Generally, the only way to recover files without their involvement is to restore files from a backup. Even if ransomware is removed/uninstalled, however, encrypted files remain inaccessible - removal of ransomware only prevents it from causing further file encryption.

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

Derp decrypt instructions

Most ransomware-type programs are quite similar - they encrypt data and provide victims with instructions about how to pay the ransom. The main differences are usually cost of decryption, and cryptographic algorithm (symmetric or asymmetric) used to encrypt data. It is generally impossible to decode files without tools held only by the developers. This is possible only in cases when ransomware is not fully developed, contains bugs, flaws, and so on. Therefore, maintain a backup of your files and store it on a remote server or unplugged storage device. Some examples of other ransomware-type programs include One, .FC, and Elder.

How did ransomware infect my computer?

Typically, cyber criminals proliferate ransomware and other malicious programs via spam campaigns, Trojans, untrustworthy software download channels, software "cracking" tools and fake software updaters. To infect computers using spam campaigns, cyber criminals send emails that contain attachments. They attach files such as Microsoft Office documents, archive files (ZIP, RAR), executables (.exe files), PDF documents, JavaScript, and others. Their main goal is to trick recipients into opening the attachment, which then installs malware. Trojans are malicious programs that, if already installed on the system, open 'backdoors' for other malware. They cause chain infections by installing additional malware. Examples of untrustworthy software download sources are free file hosting, freeware download websites, Peer-to-Peer (P2P) networks such as torrent clients, eMule, unofficial pages, third party downloaders, etc. Cyber criminals use them to upload malicious files, which they disguise as harmless and legitimate. Opening files downloaded through channels of this kind risks installation of malicious programs. Software "cracking" tools are programs that some people use to activate licensed software free of charge, however, they are often designed to proliferate and install malware. Fake software updaters infect computers by exploiting bugs/flaws of outdated software installed on the computer, or by installing malicious programs rather than updating installed ones.

Threat Summary:
Name Derp virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .derp
Ransom Demanding Message _readme.txt
Ransom Amount $490/$980
Cyber Criminal Contact gorentos@bitmessage.ch, gerentosrestore@firemail.cc
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 malware is designed to show a fake Windows Update window and modify the Windows "hosts" file to prevent users from accessing cyber security websites (more information below).
Distribution methods Infected email attachments (macros), torrent websites, malicious ads, unofficial activation and updating tools.
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.
Malware Removal (Windows)

To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Malwarebytes.
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How to protect yourself from ransomware infections

If an email is received from a suspicious and/or unknown address, is irrelevant and contains an attachment or link, do not open it. Download all software from official, trustworthy websites and via direct links. Third party downloaders, installers, Peer-to-peer networks, and other such tools and sources can be used to distribute unwanted software - do not use them to download or install programs. Installed software and operating systems should be updated using tools or implemented functions provided by official developers. If software is not free (requires activation and payment), do not use unofficial tools ('cracks') - this is illegal and often leads to download/installation of malware. Finally, systems should be regularly scanned with a reputable antivirus or anti-spyware suite - keep this software up-do-date. If your computer is already infected with Derp, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in Derp ransomware text file ("_readme.txt"):

ATTENTION!

Don't worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with
strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
hxxps://we.tl/t-vzAZbtWtGh
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that's price for you is $490.
Please note that you'll never restore your data without payment.
Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.


To get this software you need write on our e-mail:
gorentos@bitmessage.ch

Reserve e-mail address to contact us:
gerentosrestore@firemail.cc

Your personal ID:
-

Screenshot of files encrypted by Derp (".derp" extension):

Files encrypted by Derp

Screenshot of fake Windows update pop-up displayed during the encryption:

Fake Windows pop-up displayed by Derp during the encryption

IMPORTANT NOTE! - As well as encrypting data, ransomware-type infections from the Djvu malware family also add a number of entries to the Windows "hosts" file. The entries contain URLs of various websites, most of which are related to malware removal. This is done to prevent users from accessing malware security websites and seeking help. Our website (PCrisk.com) is also on the list. Removing these entries, however, is simple - you can find detailed instructions in this article (note that, although the steps are shown in the Windows 10 environment, the process is virtually identical on all versions of the Microsoft Windows operating system).

Screenshot of websites added to Windows hosts file:

Tro Ransomware adding websites to Windows Hosts file

There are currently two versions of Djvu ransomware infections: old and new. The old versions were designed to encrypt data by using a hard-coded "offline key" whenever the infected machine had no internet connection or the server was timing out/not responding. Therefore, some victims were able to decrypt data using a tool developed by cyber security researcher, Michael Gillespie, however, since the encryption mechanism has been slightly changed (hence the new version, released in August, 2019), the decrypter no longer works and it is not supported anymore. If your data has been encrypted by an older version, you might be able to restore it with the another tool developed by Emsisoft and Michael Gillespie. It supports a total of 148 Djvu variants and you can find more information, as well as download link and decryption instructions on Emsisoft's official web page.

Screenshot of Djvu decryption tool by Emsisoft and Michael Gillespie:

Djvu ransomware decrypter by Michael Gillespie and Emsisoft

Additionally, Emsisoft is now providing a service that allows data decryption (again, only if it was encrypted by Djvu variants released before August, 2019) for those victims who have copies of files before and after encryption. Victims simply upload the original and encrypted file to Emsisoft's Djvu decryption web page and download the aforementioned decryption tool (the download link will be provided after uploading files). Note that file processing might take some time, so be patient. Note that the system must have an internet connection during the entire decryption process, otherwise it will fail.

Screenshot of Emsisoft Djvu decryption service web page:

Djvu ransomware decryption service by Emsisoft

Derp ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Malwarebytes is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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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 Derp 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 Derp 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 Derp 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 Derp 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 Derp, 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 Derp 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, and 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 Derp 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 malware activity level today:

Medium threat activity

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

QR Code
Derp virus 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 Derp virus on your mobile device.
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