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How to remove Exx ransomware and stop it from encrypting more files?

Also Known As: Exx virus
Damage level: Severe

What is the Exx ransomware?

Exx is a piece of malicious software categorized as ransomware. Systems infected with this malware have their data encrypted (files rendered inaccessible) and receive ransom demands for the decryption (access recovery).

During the encryption process, affected files are appended with the ".exx" extension. For example, a file originally named something like "1.jpg" would appear as "1.jpg.exx" - following encryption.

After the completion of this process, Exx ransomware displays a pop-up window, which contains a ransom note. Additionally, this malicious program changes the desktop wallpaper to HELP_RESTORE_FILES.bmp" and drops "HELP_RESTORE_FILES.txt" files into compromised folders. The wallpaper and text files contain identical ransom-demanding messages.

The text presented in the desktop wallpaper ("HELP_RESTORE_FILES.bmp") and dropped text files ("HELP_RESTORE_FILES.txt") informs victims that their documents, photos, databases, and other important files have been encrypted using the RSA-2048 cryptographic algorithm. To recover the data - the private decryption key must be purchased from the cyber criminals responsible for the infection.

If Exx ransomware's pop-up window is not being displayed, victims are to follow the steps listed in the wallpaper/ text files to initiate the recovery process. Any one of the listed websites has to be accessed - to get further instructions. Should the public sites be unavailable, the alternative is accessing the webpage that can only be opened via the Tor browser.

If this site likewise cannot be reached, victims are to retry an hour later. The note in the pop-up repeats much of the previously mentioned information.

However, it also states that the decryption key will not be stored indefinitely. How much time remains until the private key is deleted can be checked on the timer presented in the pop-up window.

Furthermore, the message warns that attempting to remove or corrupt the Exx program - will result in permanent data loss. Unfortunately, in many cases of ransomware infections, decryption is impossible without the cyber criminals' involvement.

It might be if the malware is still in development. Whatever the case, it is expressly advised against communicating with and/or paying criminals. Despite meeting the ransom demands, victims often do not receive the promised decryption key/tools.

Therefore, the data remains encrypted (essentially inaccessible and worthless), and victims experience a financial loss. Removing Exx ransomware from the opening system will prevent it from further encryptions.

However, removal will not restore already affected files. The sole solution is recovering the files from a backup, if one was created before the infection and stored in a different location.

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

Exx decrypt instructions (pop-up)

CryT0YKIANOLamarArm, and Qscx are some examples of the ransomware-type programs. They are designed to encrypt data and demand payment for the decryption.

There are two primary differences in-between these programs/infections - the cryptographic algorithms they use (symmetric or asymmetric) and the ransom size. Digital currencies (e.g., cryptocurrencies, pre-paid vouchers, gift cards, etc.) are usually used because their transactions are difficult/impossible to trace.

To avoid permanent data loss, it is strongly recommended to keep backups in remote servers and/or unplugged storage devices. Preferably, backup copies should be stored in multiple separate locations.

How did ransomware infect my computer?

Ransomware and other malware are distributed via spam campaigns - mass-scale operations during which thousands of deceptive emails are sent. These letters are typically presented as "official", "urgent", "priority", "urgent", and similar.

The scam emails have virulent files attached to them, or they contain download links of such content. Malicious files can be in various formats, e.g., PDF and Microsoft Office documents, archives (ZIP, RAR, etc.), executables (.exe, .run, etc.), JavaScript, and so forth.

When the files are executed, run, or otherwise opened - the infection process (i.e., malware download/installation) is triggered. Malware (ransomware included) is often disguised as or bundled with ordinary software/media and proliferated via untrustworthy download sources (e.g., unofficial and free file-hosting, Peer-to-Peer sharing networks, and other third-party downloaders).

Illegal activation ("cracking") tools and fraudulent updates are prime examples of content used to spread malicious software. "Cracks" can infect systems instead of activating licensed products.

Fake updaters cause infections by abusing weaknesses of outdated programs and/or by installing malware rather than the promised updates.

Threat Summary:
Name Exx virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .exx
Ransom Demanding Message Text presented in the pop-up window, HELP_RESTORE_FILES.txt, and HELP_RESTORE_FILES.bmp (desktop wallpaper)
Cyber Criminal Contact Website on Tor network
Detection Names AVG (Win32:CryptoWall-U [Trj]), BitDefender (Trojan.Ransom.AJM), ESET-NOD32 (A Variant Of Win32/Injector.CANT), Fortinet (W32/Injector.CANT!tr), Malwarebytes (Trojan.MalPack.GS), 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?

It is recommended to exercise caution with incoming emails. Suspicious and irrelevant emails must not be opened, especially any attachments or links present in them.

Additionally, all downloads must be performed from official and verified channels. It is just as important to activate and update programs with tools/functions provided by genuine developers. To ensure device integrity and user safety, it is crucial to have a reputable anti-virus/anti-spyware suite installed and updated.

This software has to be used to run regular system scans and to remove detected threats and issues. If your computer is already infected with Exx, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate this ransomware.

Text presented in Exx ransomware's pop-up window:

All your important files have been encrypted!

 

Your personal files(including those on the network disks, USB, etc) have been encrypted:
photos, videos, documents, etc. Click "Show files" Button to view a complete list of encrypted files,
and you can personally verify this.

 

Encryption was made using a unique strongest RSA-2048 public key generated for this computer.
To decrypt files you need to acquire the private key.
The only copy of the private key, which will allow you to decrypt your files,is located on a secret TOR
server in the Internet; the server will eliminate the key after a time period specified in this window.
Once this has been done, nobody will ever be able to restore your files...
In order to decrypt files press button to open your personal page and follow the instruction.
[File decryption button]
in case of "File decryption button" malfunction use one of public gates:
hxxp://iq3ahijcfeont3xx.sm4i8smr3f43.com or
hxxps://iq3ahijcfeont3xx.tor2web.blutmagie.de

 

Use you Bitcoin address to enter the site: 15Wgt4Fpgg6Mxai1BJ3yUJrznL9w79FJpm
[Click to copy Bitcoin address to clipboard]
if both button and reserve gates not opening, please follow these steps:
You must install TOR browser www.torproject.org/projects/torbrowser.html.en
After installation,run the browser and ender address iq3ahijcfeont3xx.onion
Follow the instructions on the web-site. We remind you that the sooner you do so,
the more chances are left to recover the files.

 

There is no other way to restore your files except of making the payment.
Any attempt to remove or corrupt this software will result in immediate
elimination of the private key by the server.

 

[Show files] [Enter Decrypt Key]

Screenshot of Exx's text file ("HELP_RESTORE_FILES.txt"):

Exx ransomware text file (HELP_RESTORE_FILES.txt)

Screenshot of Exx's desktop wallpaper ("HELP_RESTORE_FILES.bmp"):

Exx ransomware wallpaper (HELP_RESTORE_FILES.bmp)

Text presented in Exx's text files and desktop wallpaper ("HELP_RESTORE_FILES.txt" and "HELP_RESTORE_FILES.bmp"):

All your documents, photos, databases and other important files have been encrypted
with strongest encryption RSA-2048 key, generated for this computer.

 

Private decryption key is stored on a secret Internet server and nobody can
decrypt your files until you pay and obtain the private key.

 

If you see the main encryptor red window, examine it and follow the instructions.
Otherwise, it seems that you or your antivirus deleted the encryptor program.
Now you have the last chance to decrypt your files.
Open in your browser one of the links:
hxxp://iq3ahijcfeont3xx.fenaow48fn42.com
hxxp://iq3ahijcfeont3xx.sm4i8smr3f43.com
hxxps://iq3ahijcfeont3xx.tor2web.blutmagie.de
They are public gates to the secret server.
Copy and paste the following Bitcoin address in the input form on server. Avoid missprints.
15Wgt4Fpgg6Mxai1BJ3yUJrznL9w79FJpm
Follow the instructions on the server.

 

If you have problems with gates, use direct connection:
1. Download Tor Browser from hxxp://torproject.org
2. In the Tor Browser open the hxxp://iq3ahijcfeont3xx.onion/  
   Note that this server is available via Tor Browser only.
   Retry in 1 hour if site is not reachable.
Copy and paste the following Bitcoin address in the input form on server. Avoid missprints.
15Wgt4Fpgg6Mxai1BJ3yUJrznL9w79FJpm
Follow the instructions on the server.

Screenshot of files encrypted by Exx ransomware (".exx" extension):

Files encrypted by Exx ransomware (.exx extension)

Exx ransomware removal:

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Video suggesting what steps should be taken in case of a ransomware infection:

Quick menu:

Reporting ransomware to authorities:

If you are a victim of a ransomware attack we recommend reporting this incident to authorities. By providing information to law enforcement agencies you will help track cybercrime and potentially assist in the prosecution of the attackers. Here's a list of authorities where you should report a ransomware attack. For the complete list of local cybersecurity centers and information on why you should report ransomware attacks, read this article.

List of local authorities where ransomware attacks should be reported (choose one depending on your residence address):

Isolating the infected device:

Some ransomware-type infections are designed to encrypt files within external storage devices, infect them, and even spread throughout the entire local network. For this reason, it is very important to isolate the infected device (computer) as soon as possible.

Step 1: Disconnect from the internet.

The easiest way to disconnect a computer from the internet is to unplug the Ethernet cable from the motherboard, however, some devices are connected via a wireless network and for some users (especially those who are not particularly tech-savvy), disconnecting cables may seem troublesome. Therefore, you can also disconnect the system manually via Control Panel:

Navigate to the "Control Panel", click the search bar in the upper-right corner of the screen, enter "Network and Sharing Center" and select search result: Disconnecting computer from the Internet (step 1)

Click the "Change adapter settings" option in the upper-left corner of the window: Disconnecting computer from the Internet (step 2)

Right-click on each connection point and select "Disable". Once disabled, the system will no longer be connected to the internet. To re-enable the connection points, simply right-click again and select "Enable". Disconnecting computer from the Internet (step 3)

Step 2: Unplug all storage devices.

As mentioned above, ransomware might encrypt data and infiltrate all storage devices that are connected to the computer. For this reason, all external storage devices (flash drives, portable hard drives, etc.) should be disconnected immediately, however, we strongly advise you to eject each device before disconnecting to prevent data corruption:

Navigate to "My Computer", right-click on each connected device, and select "Eject": Ejecting external storage devices

Step 3: Log-out of cloud storage accounts.

Some ransomware-type might be able to hijack software that handles data stored within "the Cloud". Therefore, the data could be corrupted/encrypted. For this reason, you should log-out of all cloud storage accounts within browsers and other related software. You should also consider temporarily uninstalling the cloud-management software until the infection is completely removed.

Identify the ransomware infection:

To properly handle an infection, one must first identify it. Some ransomware infections use ransom-demand messages as an introduction (see the WALDO ransomware text file below).

Identify ransomware-type infection (step 1)

This, however, is rare. In most cases, ransomware infections deliver more direct messages simply stating that data is encrypted and that victims must pay some sort of ransom. Note that ransomware-type infections typically generate messages with different file names (for example, "_readme.txt", "READ-ME.txt", "DECRYPTION_INSTRUCTIONS.txt", "DECRYPT_FILES.html", etc.). Therefore, using the name of a ransom message may seem like a good way to identify the infection. The problem is that most of these names are generic and some infections use the same names, even though the delivered messages are different and the infections themselves are unrelated. Therefore, using the message filename alone can be ineffective and even lead to permanent data loss (for example, by attempting to decrypt data using tools designed for different ransomware infections, users are likely to end up permanently damaging files and decryption will no longer be possible even with the correct tool).

Another way to identify a ransomware infection is to check the file extension, which is appended to each encrypted file. Ransomware infections are often named by the extensions they append (see files encrypted by Qewe ransomware below).

Identify ransomware-type infection (step 2)

This method is only effective, however, when the appended extension is unique - many ransomware infections append a generic extension (for example, ".encrypted", ".enc", ".crypted", ".locked", etc.). In these cases, identifying ransomware by its appended extension becomes impossible.

One of the easiest and quickest ways to identify a ransomware infection is to use the ID Ransomware website. This service supports most existing ransomware infections. Victims simply upload a ransom message and/or one encrypted file (we advise you to upload both if possible).

Identify ransomware-type infection (step 3)

The ransomware will be identified within seconds and you will be provided with various details, such as the name of the malware family to which the infection belongs, whether it is decryptable, and so on.

Example 1 (Qewe [Stop/Djvu] ransomware):

Identify ransomware-type infection (step 4)

Example 2 (.iso [Phobos] ransomware):

Identify ransomware-type infection (step 5)

If your data happens to be encrypted by ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, a ransom message title, file extension, provided contact emails, crypto wallet addresses, etc.).

Search for ransomware decryption tools:

Encryption algorithms used by most ransomware-type infections are extremely sophisticated and, if the encryption is performed properly, only the developer is capable of restoring data. This is because decryption requires a specific key, which is generated during the encryption. Restoring data without the key is impossible. In most cases, cybercriminals store keys on a remote server, rather than using the infected machine as a host. Dharma (CrySis), Phobos, and other families of high-end ransomware infections are virtually flawless, and thus restoring data encrypted without the developers' involvement is simply impossible. Despite this, there are dozens of ransomware-type infections that are poorly developed and contain a number of flaws (for example, the use of identical encryption/decryption keys for each victim, keys stored locally, etc.). Therefore, always check for available decryption tools for any ransomware that infiltrates your computer.

Finding the correct decryption tool on the internet can be very frustrating. For this reason, we recommend that you use the No More Ransom Project and this is where identifying the ransomware infection is useful. The No More Ransom Project website contains a "Decryption Tools" section with a search bar. Enter the name of the identified ransomware, and all available decryptors (if there are any) will be listed.

Searching for ransomware decryption tools in nomoreransom.org website

Restore files with data recovery tools:

Depending on the situation (quality of ransomware infection, type of encryption algorithm used, etc.), restoring data with certain third-party tools might be possible. Therefore, we advise you to use the Recuva tool developed by CCleaner. This tool supports over a thousand data types (graphics, video, audio, documents, etc.) and it is very intuitive (little knowledge is necessary to recover data). In addition, the recovery feature is completely free.

Step 1: Perform a scan.

Run the Recuva application and follow the wizard. You will be prompted with several windows allowing you to choose what file types to look for, which locations should be scanned, etc. All you need to do is select the options you're looking for and start the scan. We advise you to enable the "Deep Scan" before starting, otherwise, the application's scanning capabilities will be restricted.

Recuva data recovery tool wizard

Wait for Recuva to complete the scan. The scanning duration depends on the volume of files (both in quantity and size) that you are scanning (for example, several hundred gigabytes could take over an hour to scan). Therefore, be patient during the scanning process. We also advise against modifying or deleting existing files, since this might interfere with the scan. If you add additional data (for example, downloading files/content) while scanning, this will prolong the process:

Recuva data recovery tool scan time

Step 2: Recover data.

Once the process is complete, select the folders/files you wish to restore and simply click "Recover". Note that some free space on your storage drive is necessary to restore data:

Recuva data recovery tool recovering data

Create data backups:

Proper file management and creating backups is essential for data security. Therefore, always be very careful and think ahead.

Partition management: We recommend that you store your data in multiple partitions and avoid storing important files within the partition that contains the entire operating system. If you fall into a situation whereby you cannot boot the system and are forced to format the disk on which the operating system is installed (in most cases, this is where malware infections hide), you will lose all data stored within that drive. This is the advantage of having multiple partitions: if you have the entire storage device assigned to a single partition, you will be forced to delete everything, however, creating multiple partitions and allocating the data properly allows you to prevent such problems. You can easily format a single partition without affecting the others - therefore, one will be cleaned and the others will remain untouched, and your data will be saved. Managing partitions is quite simple and you can find all the necessary information on Microsoft's documentation web page.

Data backups: One of the most reliable backup methods is to use an external storage device and keep it unplugged. Copy your data to an external hard drive, flash (thumb) drive, SSD, HDD, or any other storage device, unplug it and store it in a dry place away from the sun and extreme temperatures. This method is, however, quite inefficient, since data backups and updates need to be made regularly. You can also use a cloud service or remote server. Here, an internet connection is required and there is always the chance of a security breach, although it's a really rare occasion.

We recommend using Microsoft OneDrive for backing up your files. OneDrive lets you store your personal files and data in the cloud, sync files across computers and mobile devices, allowing you to access and edit your files from all of your Windows devices. OneDrive lets you save, share and preview files, access download history, move, delete, and rename files, as well as create new folders, and much more.

You can back up your most important folders and files on your PC (your Desktop, Documents, and Pictures folders). Some of OneDrive’s more notable features include file versioning, which keeps older versions of files for up to 30 days. OneDrive features a recycling bin in which all of your deleted files are stored for a limited time. Deleted files are not counted as part of the user’s allocation.

The service is built using HTML5 technologies and allows you to upload files up to 300 MB via drag and drop into the web browser or up to 10 GB via the OneDrive desktop application. With OneDrive, you can download entire folders as a single ZIP file with up to 10,000 files, although it can’t exceed 15 GB per single download.

OneDrive comes with 5 GB of free storage out of the box, with an additional 100 GB, 1 TB, and 6 TB storage options available for a subscription-based fee. You can get one of these storage plans by either purchasing additional storage separately or with Office 365 subscription.

Creating a data backup:

The backup process is the same for all file types and folders. Here’s how you can back up your files using Microsoft OneDrive

Step 1: Choose the files/folders you want to backup.

Click the OneDrive icon in the taskbar

Click the OneDrive cloud icon to open the OneDrive menu. While in this menu, you can customize your file backup settings.

Select Help & Settings and click Settings

Click Help & Settings and then select Settings from the drop-down menu.

Select the Backup tab and click Manage backup

Go to the Backup tab and click Manage backup.

Select folders to backup and click Start backup

In this menu, you can choose to backup the Desktop and all of the files on it, and Documents and Pictures folders, again, with all of the files in them. Click Start backup.

Now, when you add a file or folder in the Desktop and Documents and Pictures folders, they will be automatically backed up on OneDrive.

To add folders and files, not in the locations shown above, you have to add them manually.

Select a file manually and copy it

Open File Explorer and navigate to the location of the folder/file you want to backup. Select the item, right-click it, and click Copy.

Paste the copied file in the OneDrive folder to create a backup

Then, navigate to OneDrive, right-click anywhere in the window and click Paste. Alternatively, you can just drag and drop a file into OneDrive. OneDrive will automatically create a backup of the folder/file.

File statuses in OneDrive folder

All of the files added to the OneDrive folder are backed up in the cloud automatically. The green circle with the checkmark in it indicates that the file is available both locally and on OneDrive and that the file version is the same on both. The blue cloud icon indicates that the file has not been synced and is available only on OneDrive. The sync icon indicates that the file is currently syncing.

Click Help & Settings and click View Online

To access files only located on OneDrive online, go to the Help & Settings drop-down menu and select View online.

Click the Settings cog and click Options

Step 2: Restore corrupted files.

OneDrive makes sure that the files stay in sync, so the version of the file on the computer is the same version on the cloud. However, if ransomware has encrypted your files, you can take advantage of OneDrive’s Version history feature that will allow you to restore the file versions prior to encryption.

Microsoft 365 has a ransomware detection feature that notifies you when your OneDrive files have been attacked and guide you through the process of restoring your files. It must be noted, however, that if you don’t have a paid Microsoft 365 subscription, you only get one detection and file recovery for free.

If your OneDrive files get deleted, corrupted, or infected by malware, you can restore your entire OneDrive to a previous state. Here’s how you can restore your entire OneDrive:

restore-your-onedrive

1. If you're signed in with a personal account, click the Settings cog at the top of the page. Then, click Options and select Restore your OneDrive.

If you're signed in with a work or school account,  click the Settings cog at the top of the page. Then, click Restore your OneDrive.

2. On the Restore your OneDrive page, select a date from the drop-down list. Note that if you're restoring your files after automatic ransomware detection, a restore date will be selected for you.

3. After configuring all of the file restoration options, click Restore to undo all the activities you selected.

The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups.

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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.

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