How to remove CILLA ransomware from your operating system

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

CILLA ransomware removal instructions

What is CILLA?

CILLA is malicious software belonging to the GlobeImposter ransomware family. It operates by encrypting data and demanding ransom payments for decryption. During this process, all compromised files are renamed with the ".CILLA" extension. For example, a filename such as "1.jpg" becomes "1.jpg.CILLA". After this process is finished, CILLA creates an HTML file named "how_to_back_files.html" and stores it in each affected folder.

The text presented in the HTML file informs victims that their data has been encrypted. It states that the only way to recover the files is to obtain a decryptor from developers of CILLA. To receive further instructions, users are instructed to contact them via the email addresses provided. The victims' messages must contain their IDs (listed in "how_to_back_files.HTML") and one encrypted file (image or text file) for decryption free of charge. The cyber criminals behind this infection will then return the restored file, assign the payment amount, and provide details about how to make it. Once ransoms are paid, the message informs users that they will receive the necessary tools to decrypt their data. Additionally, the message warns users not to trust third parties to retrieve their files. Removing CILLA, running an anti-virus software and attempting manual decryption will apparently lead to permanent data loss. The decryptors of other affected users are said to be incompatible, as each encryption key is unique. Unfortunately, in most cases of ransomware infections, manual decryption with third party decryption tools is impossible, unless, in rare cases, the malware is still in development and/or has key flaws/bugs. Regardless, you are strongly advised against contacting or meeting the demands of cyber criminals. Despite paying, victims do not receive the promised decryption tools/software. Therefore, their files remain encrypted and useless. While removal of this malicious program will not restore compromised data, it will prevent CILLA from further encryption. The only viable solution is to recover files from a backup, if one was created before the infection and was stored separately.

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

CILLA decrypt instructions

MT88BigBossRoss, and JavaRatty are several examples of other ransomware programs. All infections within this category encrypt files and demand payment for decryption. They differ by the cryptographic algorithm they use (symmetric or asymmetric) and ransom size. The latter commonly ranges between three-digit and four-digit sums. Digital currencies (e.g. cryptocurrencies, pre-paid vouchers, etc.) are preferred, since these transactions are difficult/impossible to trace. To ensure data safety, keep backups on unplugged storage devices and/or remote servers. Store multiple backup copies in different locations.

How did ransomware infect my computer?

The most common methods of ransomware and other malware proliferation are via trojans, spam campaigns, untrustworthy download sources, illegal activation tools ("cracks") and fake updaters. Trojans are malicious programs, capable of causing chain infections (i.e., they download/install additional malware). Massive scale spam campaigns are used to send deceptive emails, with infectious files attached (or containing links leading to such files). This mail is usually marked as "official", "important", "urgent", "priority" and so on. The attachments come in various formats (e.g. archive and executable files, Microsoft Office and PDF documents, JavaScript, etc.). When run, executed or otherwise opened, this initiates the infection process. Peer-to-Peer sharing networks (BitTorrent, eMule, Gnutella, etc.), unofficial and free file-hosting websites, third party downloaders and similar sources are classed as untrustworthy. Therefore, they are more likely to contain malicious content (e.g. disguised as normal software and/or bundled with it). Rather than activating ("cracking") licensed products, illegal activation tools often download/install malware. Fake updaters cause infections by exploiting flaws present in outdated programs and/or simply install malware, rather than the promised updates.

Threat Summary:
Name CILLA virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .CILLA
Ransom Demanding Message how_to_back_files.html
Cyber Criminal Contact and
Detection Names Avast (Win32:Trojan-gen), BitDefender (Generic.Ransom.GlobeImposter.4361C1A9), ESET-NOD32 (A Variant Of Win32/Filecoder.FV), 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)

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

Do not open suspicious/irrelevant emails. Any attachments or links found in dubious mail must never be opened, as these files are the origin of a potential system infection. You are advised to use official and verified download channels. Software should be activated and updated using functions/tools provided by genuine developers. Do not use illegal activation tools ("cracks") or third party updaters, due to high-risk of malware installation. Have a reputable anti-virus/anti-spyware suite installed and kept updated. This software is to be set to perform regular system scans and to remove detected threats/issues. If your computer is already infected with CILLA, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in CILLA ransomware HTML file ("how_to_back_files.html"):



To recover data you need decryptor.
To get the decryptor you should:
Send 1 test image or text file or
In the letter include your personal ID (look at the beginning of this document).

We will give you the decrypted file and assign the price for decryption all files
After we send you instruction how to pay for decrypt and after payment you will receive a decryptor and instructions We can decrypt one file in quality the evidence that we have the decoder.

Only and can decrypt your files
Do not trust anyone and
Do not attempt to remove the program or run the anti-virus tools
Attempts to self-decrypting files will result in the loss of your data
Decoders other users are not compatible with your data, because each user's unique encryption key

Screenshot of files encrypted by CILLA (".CILLA" extension):

Files encrypted by CILLA

CILLA 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 CILLA 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 CILLA 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 CILLA 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 CILLA 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 CILLA, 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 CILLA 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 CILLA 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 since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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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
CILLA 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 CILLA virus on your mobile device.
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