How to eliminate the Acute ransomware infection

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

Acute ransomware removal instructions

What is Acute?

First discovered by GrujaRS, Acute is a new variant of high-risk ransomware called Phobos. The purpose of this ransomware is to encrypt data so that developers can make ransom demands. Acute is designed to rename each compromised file by appending the victim's unique ID, developer's email address, and ".acute" extension. For example, "sample.jpg" might be renamed to a filename such as "[1E857D00-1096].[].acute". Following successful encryption, Acute generates two files ("info.txt" and "info.hta"), placing them on the desktop.

The new text file ("info.txt") contains a short message informing victims of the encryption and encouraging them to contact Acute's developers. Meanwhile, an HTML application ("info.hta") displays a pop-up window, which delivers much more information. It states that files are compromised and that victims must purchase a decryption tool to restore them. The encryption algorithm used by Acute is currently unknown, however, each victim gets a unique decryption key necessary to restore files. All keys are stored on a remote server controlled by cyber criminals (Acute's developers). To obtain a key, or rather a decryption tool with the key embedded within, each victim must pay a ransom. The cost is not specified - these details are provided via email. It is only stated that payment must be submitted using the Bitcoin cryptocurrency. In addition, criminals offer free decryption of five files (up to 10 MB in total, non-archived) as 'proof' that they are capable of cracking the encryption. Regardless of the cost, do not pay. Most ransomware developers ignore victims, once payments are submitted. Therefore, ignore all requests to submit payments or even contact these people, since this will deliver no positive result and you will simply support cyber criminals' malicious businesses. Unfortunately, there are no tools capable of restoring data encrypted by Acute free of charge. Therefore, you can only restore everything from a backup, if one has been created.

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

Acute decrypt instructions

Internet is full of ransomware-type infections that share similarities with Acute. Rabbit4444TodarfoSTE - the list goes on. Most of these infections encrypt data and make ransom demands. There are typically just two major differences: 1) size of ransom, and; 2) type of encryption algorithm used. Unfortunately, encryptions are usually performed using algorithms that generate unique decryption keys (e.g., RSA, AES, and similar). Therefore, unless the malware has bugs or flaws, restoring files without developers' involvement is impossible. We strongly recommend that you maintain regular data backups, however, store them on an unplugged storage device (e.g., Flash drive, external hard drive or similar) or remote server (e.g., Cloud), since locally stored backups are compromised together with regular data. Additionally, have multiple backup copies stored in different locations, since there is always a chance that servers/storage devices can be damaged.

How did ransomware infect my computer?

Ransomware-type infections such as Acute are typically distributed using the following tools/methods: trojans, fake software update tools, fake software cracks, third party software download sources, and spam email campaigns. Trojans are small applications that stealthily infiltrates computers to inject them with additional malware. Fake software updaters are typically designed to infect systems by exploiting outdated software bugs/flaws or merely downloading and installing malware rather than updates. Cracking tools allow users to bypass paid software activation and gain access to features, however, since most cracks are fake, users often end up infecting their computers rather than gaining access to any paid software. Third party download sources (e.g., freeware download websites, free file hosting sites, Peer-to-Peer [P2P] networks [eMule, torrents, etc.] and similar) are used to present malware as legitimate software. In this way, criminals trick users into manually downloading and installing malware. The same applies to spam email campaigns, which are used to send hundreds of thousands of deceptive emails that present malicious attachments as 'important documents' (receipts, invoices, bills, etc.) Opening then results in various malware infections. The main reasons for computer infections are poor knowledge of these threats and careless behavior.

Threat Summary:
Name Acute virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .acute (this ransomware also appends filenames with the victim's unique ID and developer's email address).
Ransom Demanding Message info.hta HTML application and info.txt text file
Cyber Criminal Contact,
Detection Names Avast (Win32:Trojan-gen), BitDefender (Gen:Variant.Ransom.Phobos.28), ESET-NOD32 (A Variant Of Win32/Filecoder.Phobos.A), 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.

To eliminate Acute 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?

The main reasons for computer infections are poor knowledge of these threats and careless behavior. The key to safety is caution. Therefore, pay attention when browsing the internet and downloading/installing/updating software. Handle all email attachments with care. Email attachments that are irrelevant or do not concern you should never be opened. The same applies to links/files received from suspicious/unrecognizable email addresses. Download applications only from official sources and, if possible, use direct download links. Keeping installed applications/operating system up-to-date is also extremely important. To achieve this, however, use only implemented functions or tools provided by the official developer. Third party downloaders, installers and updaters usually include rogue applications, and thus such tools should never be used. Software piracy is a cyber crime, and since most cracking tools are fake, the risk of infection is extremely high. Therefore, never try to activate software using third party/illegal tools. Have a reputable anti-virus/anti-spyware suite installed and running. This software is capable of detecting and eliminating malware before it damages the system. If your computer is already infected with Acute, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in Acute ransomware pop-up window ("info.hta" - HTML application):

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
Write this ID in the title of your message 1E857D00-1096
If there is no response from our mail, you can install the Jabber client and write to us in support of
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 decryption 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 10Mb (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.
Also you can find other places to buy Bitcoins and beginners guide here:
Jabber client installation instructions:
Download the jabber (Pidgin) client from hxxps://
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 -
Create a password
At the bottom, put a tick "Create account"
Click add
If you selected "domain" -, then a new window should appear in which you will need to re-enter your data:
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://
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.

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

Acute text file

Text presented within this file:

!!! All of your files are encrypted !!!
To decrypt them send e-mail to this address:
If there is no response from our mail, you can install the Jabber client and write to us in support of

Screenshot of files encrypted by Acute (".acute" extension):

Files encrypted by Acute

Acute ransomware removal:

Instant automatic removal of Acute 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 Acute 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 Acute 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 Acute 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 Acute 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 Acute 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 Acute, 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 Acute 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 Acute 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.

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

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

QR Code
Acute virus QR code
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