How to uninstall Dewar ransomware from the operating system

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

Dewar ransomware removal instructions

What is Dewar?

Dewar is a malicious program belonging to the Phobos ransomware family. Systems infected with this malware have their data encrypted and users receive ransom demands for decryption. During the encryption process, all affected files are renamed according to the following pattern: original filename, unique ID, developer's email address and the ".dewar" extension. For example, a file like "1.jpg" would appear as something similar to "1.jpg.id[1E857D00-2718].[kryzikrut@airmail.cc].dewar". Updated variants of this ransomware use ".[zalarubata@airmail.cc].dewar", ".[cristianominogue@cock.li].dewar", ".[yanyddiel@airmail.cc].dewar", ".[zanolven@airmail.cc].dewar", ".[creampie@ctemplar.com].dewar", ".[correctway@qq.com].dewar", ".[red@gytmail.com].dewar", ".[waleon@airmail.cc].dewar", ".[wang_team777@aol.com].dewar", ".[mccunesina@aol.com].dewar", ".[howtodecrypt45@cock.li].dewar", ".[danianci@airmail.cc].dewar", ".[deltatechit@protonmail.com].dewar", ".[gabriele.keeler@aol.com].dewar", ".[pennmargery@aol.com].dewar", ".[walmesleyemerita@aol.com].dewar", ".[Jamees0101@outlook.com].dewar", ".[chagenak@airmail.cc].dewar" and ".[mr.helper@qq.com].dewar" extensions for encrypted files. After this process is complete, a text file ("info.txt") and an HTML application ("info.hta") are dropped onto the desktop. Both of these files contain ransom messages.

The text file states that the victims' data has been encrypted. To get further instructions about how to decrypt it, they must establish contact with the cyber criminals behind the infection via email, Telegram or Jabber instant messaging platforms. The ransom message in the pop-up window ("info.hta") provides more information. This message repeats the initial statement concerning file encryption and adds that, when initiating contact with the ransomware developers, users must include their IDs (found in the pop-up and filenames of each encrypted file). While the size of ransom is not specified (this will depend on how quickly contact is established), victims are informed that it must be paid in the Bitcoin cryptocurrency. Links are provided for how and from where to acquire Bitcoins. Users are warned that renaming compromised files or attempting decryption with third party tools/software can result in permanent data loss. Prior to making payment, victims can test decryption by sending up to five encrypted files. The size of these test files cannot exceed 4 MB in total. Additionally, they must not be archived or contain valuable information (e.g. databases, backups, large excel sheets, etc.). Lengthy instructions are provided on how to install and create an account in Jabber (Pidgin instant messaging client). Should these directions be confusing, the message suggests searching installation tutorials on YouTube. Unfortunately, in most cases of ransomware infections, decryption is impossible without the involvement of the criminals responsible, unless the malware in question is still in development or has bugs/flaws. Whatever the case, you are strongly advised against paying cyber criminals. Despite meeting the ransom demands, victims do not receive the promised decryption tools/software. Therefore, their data remains encrypted and useless, and they also experience significant financial loss. To prevent Dewar from further encryption, it must be removed from the operating system, however, removal will not restore already affected files. The only viable solution is recovering data from a backup, if one was created before the infection and was stored in a different location.

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

Dewar decrypt instructions (info.hta)

2NEWThe Cursed Murderer, and Alka are some examples of other ransomware infections. Malicious programs in this category encrypt data and demand payment for decryption tools/software. There are two main differences: the cryptographic algorithm they use (symmetric or asymmetric) and ransom size. The latter varies between three and four digit sums (in USD). To ensure data safety, you are advised to keep backups on remote servers and/or unplugged storage (preferably in several separate locations).

How did ransomware infect my computer?

Ransomware and other malware is primarily spread via trojans, spam campaigns, illegal activation tools ("cracks"), fake updaters and untrusted download sources. Trojans are malicious programs capable of causing chain infections (i.e., download/install additional malware). Spam campaigns are used to send thousands of deceptive emails with infectious files attached to (or linked inside) them. These attachments come in various formats (e.g. executable and archive files, Microsoft Office and PDF documents, JavaScript, etc.). When the dangerous files are opened, the infection is initiated. Rather than activating licensed products, illegal activation ("cracking") tools can download/install malicious software. Rogue updaters infect systems by exploiting flaws of outdated programs or simply downloading and installing malware, rather than the promised updates. Unofficial and free file-hosting sites, P2P sharing networks (BitTorrent, eMule, Gnutella, etc.), third party downloaders and other untrusted sources can offer malicious programs for download (e.g. disguised as or bundled with normal software).

Threat Summary:
Name Dewar virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .dewar (files are also appended with a unique ID and cyber criminals' email address).
Ransom Demand Message info.hta and info.txt
Cyber Criminal Contact kryzikrut@airmail.cc and kokux@tutanota.com, @hpdec (Telegram), decrypt_here@xmpp.jp (Jabber)
Detection Names Avast (Win32:Malware-gen), BitDefender (Gen:Variant.Ransom.Phobos.62), ESET-NOD32 (A Variant Of Win32/Filecoder.Phobos.C), Kaspersky (HEUR:Trojan.Win32.Generic), 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.
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.
Malware Removal (Windows)

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How to protect yourself from ransomware infections

Do not open suspicious or irrelevant emails. Furthermore, any attachments or links present in dubious mail must never be opened, since doing so can result in an infection. Use only official and verified download channels. Software should be activated and updated with tools/functions provided by genuine developers. Do not use illegal activation tools ("cracks") or third party updaters, as they can cause high-risk infections. For device safety and integrity, have a reputable anti-virus/anti-spyware suite installed and kept up to date. Furthermore, this should be used to perform regular system scans and removal of detected/potential threats. If your computer is already infected with Dewar, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in Dewar ransomware pop-up window ("info.hta"):

All your files have been encrypted!
All your files have been encrypted due to a security problem with your PC. If you want to restore them, write us to the e-mail: kryzikrut@airmail.cc and this e-mail:kokux@tutanota.com
Write this ID in the title of your message 1E857D00-2718
Our operator is available in the messenger Telegram: hxxps://telegram.org/. To find us, enter the alias @hpdec in the messenger search box.
You can install the Jabber client and write to us in support of decrypt_here@xmpp.jp
You have to pay for decryption in Bitcoins. The price depends on how fast you write to us. After payment we will send you the tool that will decrypt all your files.
Free decryption as guarantee
Before paying you can send us up to 5 files for free decryption. The total size of files must be less than 4Mb (non archived), and files should not contain valuable information. (databases,backups, large excel sheets, etc.)
How to obtain Bitcoins
The easiest way to buy bitcoins is LocalBitcoins site. You have to register, click 'Buy bitcoins', and select the seller by payment method and price.
hxxps://localbitcoins.com/buy_bitcoins
Also you can find other places to buy Bitcoins and beginners guide here:
hxxp://www.coindesk.com/information/how-can-i-buy-bitcoins/
Attention!

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.
Jabber client installation instructions:
Download the jabber (Pidgin) client from hxxps://pidgin.im/download/windows/
After installation, the Pidgin client will prompt you to create a new account.
Click "Add"
In the "Protocol" field, select XMPP
In "Username" - come up with any name
In the field "domain" - enter any jabber-server, there are a lot of them, for example - exploit.im
Create a password
At the bottom, put a tick "Create account"
Click add
If you selected "domain" - exploit.im, then a new window should appear in which you will need to re-enter your data:
User
password
You will need to follow the link to the captcha (there you will see the characters that you need to enter in the field below)
If you don't understand our Pidgin client installation instructions, you can find many installation tutorials on youtube - hxxps://www.youtube.com/results?search_query=pidgin+jabber+install

Screenshot of Dewar text file ("info.txt"):

Dewar ransomware text file (info.txt)

Text presented in this file:

!!!All of your files are encrypted!!!
To decrypt them send e-mail to this address: kryzikrut@airmail.cc and this: kokux@tutanota.com
For ease of communication, you can install the telegram messenger.
Messenger site hxxps://telegram.org/
To find us, enter the alias @hpdec in the messenger search box.
jabber: decrypt_here@xmpp.jp 

Screenshot of files encrypted by Dewar (".dewar" extension):

Files encrypted by Dewar ransomware (.dewar extension)

Dewar 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 Dewar 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 Dewar 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 Dewar 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 Dewar 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 Dewar, 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 Dewar 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 Dewar 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
Dewar 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 Dewar virus on your mobile device.
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