CMG Ransomware

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

CMG ransomware removal instructions

What is CMG?

CMG is a malicious program that is categorized as ransomware. Developers (cyber criminals) use it to blackmail people by encrypting data and making ransom demands. Once data is encrypted, it cannot be accessed or used. Note that CMG is a computer infection that belongs to the GlobeImposter ransomware family and was discovered by Michael Gillespie. It adds the ".{CALLMEGOAT@PROTONMAIL.COM}CMG" extension to every encrypted file. For example, "1.jpg" becomes "1.jpg.{CALLMEGOAT@PROTONMAIL.COM}CMG". It also generates a ransom message within the "decrypt_files.html" HTML file, which can be found in all folders containing encrypted files.

The ransom message ("decrypt_files.HTML") is a file containing instructions on how to decrypt encrypted files. It states that this can be done using a decryption program (tool). To obtain this tool, CMG's victims must send developers an email via the callmegoat@protonmail.com address containing a personal/unique ID. They offer free decryption of one file (no larger than 5 MB) as 'proof' that they are capable of decryption and have a decryption tool. Once the email is sent, they will return the decrypted file, cost of the decryption tool, and instructions on how to pay. When payment is made (ransom demands are met), the developers promise to send a tool that will decrypt the remaining encrypted files. It is also stated that only CMG's developers can decrypt files encrypted by this ransomware. Additionally, victims are urged not to try to decrypt files by (using some other tools) or run anti-virus scan since it might cause data loss or corruption. Unfortunately, to encrypt data, most cyber criminals use cryptography algorithms (symmetric or asymmetric) that make decryption without the involvement of cyber criminals impossible. Only they can provide a decryption tool. This is the case with CMG ransomware - there are no tools capable of decrypting files free of charge. In these situations, the only free solution is to restore everything from a data backup created prior to system infection and data encryption.

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

CMG decrypt instructions

There are many ransomware-type programs on the internet including, for example, Azero, Jimm, and Golden Axe. Developers use them to encrypt data and make ransom demands. Any differences are usually cryptography algorithm used to encrypt files and the cost of their decryption tool. Unfortunately, most ransomware-type programs use encryptions that are very difficult or even impossible to 'crack'. This becomes possible only if ransomware is not fully developed or contains bugs/flaws. Therefore, maintain regular backups and store them on unplugged storage devices or remote servers (such as Cloud).

How did ransomware infect my computer?

It is unknown exactly how cyber criminals proliferate CMG ransomware, however, most ransomware developers use spam campaigns, Trojans, untrustworthy software download sources, software 'cracking' tools, and fake software updaters. They attempt to infect computers through spam campaigns by sending emails that include malicious attachments or web links that lead to them. The main goal is to trick people into opening these attachments, which are usually executables (.exe files), archives (RAR, ZIP), PDF or Microsoft Office documents, JavaScript files, and so on. When opened, these malicious attachments infect computers with ransomware or other viruses. Trojans are programs that cause chain infections - they are malicious programs that download and install other malicious programs. Dubious software download channels such as free file hosting websites, freeware download websites, Peer-to-Peer networks such as torrent clients, eMule, other third party software download sources are often  used to trick people into downloading and installing malicious programs. This is achieved when they download and open infected files that cyber criminals present as legitimate. Another way to infect a computer with ransomware or other high-risk virus is through software 'cracking' tools. These programs supposedly activate software or operating systems free of charge, however, they often download/install computer infections rather. Fake (third party) software updaters infect systems by downloading malware rather than the updates or fixes, or by exploiting outdated software bugs/flaws.

Threat Summary:
Name CMG virus
Threat Type Ransomware, Crypto Virus, Files locker.
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 request 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?

To keep a computer safe from ransomware and other infections, browse the web, download, install, and update software, carefully. Avoid opening attachments that are presented in emails received from unknown or suspicious addresses. If the email seems irrelevant, do not open the attachment (or website link). All software should be downloaded using official, trustworthy sources and direct links. Third party downloaders, installers and other channels mentioned above should not be trusted or used. Do not use unofficial/third party tools to update installed software. The safest way to update software is using tools provided by official software developers. Note that software activation using 'cracking' tools is illegal. Furthermore, these tools often install malicious programs rather than bypassing paid any software activation. Finally, have anti-virus or anti-spyware software installed and enabled. If your computer is already infected with CMG, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in CMG ransomware "decrypt_files.html" HTML file:

YOUR ID (NEED FOR DECRYPT)
-

 

ENGLISH
YOUR FILES ARE ENCRYPTED!
IF YOU SEE IT - DO NOT TRY TO DECRYPT ?THE FILES YOURSELF!!!?
ALL YOUR IMPORTANT DATA HAS BEEN ENCRYPTED.

 

To decrypt all your files, you need a decryption program.
To get a program to decrypt your data you need to do a few steps:
1. To make sure that we can actually decrypt your files. You can send us a file for the test. This can be a picture or a text file. Size less than 5 MB. Send to our mail: CALLMEGOAT@PROTONMAIL.COM .
2. Send your PERSONAL ID in the letter (you will find it at the very beginning of this document)

 

3. We will decode your test file so you are sure. We will also send you the amount you need to pay to get the program to decrypt.

 

4. We will send you instructions on how to pay for the decryption program. After payment, we will send you a program and instructions on how to decrypt all the files.
ATTENTION!

 

Only we can decrypt your files.
Do not try to decrypt your files yourself. You can damage them when trying to restore
Do not run antivirus!
Email us: CALLMEGOAT@PROTONMAIL.COM immediately so we can help you. Decoders other users are not compatible with your data, because each user's unique encryption key

Screenshot of CMG ransomware HTML file:

screenshot of cmg ransomware html file

Second screenshot of CMG ransomware HTML file:

second screenshot of cmg ransomware html file

Screenshot of files encrypted by CMG (".{CALLMEGOAT@PROTONMAIL.COM}CMG" extension):

Files encrypted by CMG

CMG 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:

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 a ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, ransom message title, file extension, provided contact emails, cryptowallet 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, cyber criminals 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 EaseUS Data Recovery Wizard Pro. 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).

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EaseUS Data Recovery Wizard Pro

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Step 1: Perform a scan.

Hover your mouse over the partition you wish to scan and select "Scan". You can also select a specific folder, or click shortcut icons to scan the Desktop or Recycle Bin: Scanning the storage drive with EaseUS Data Recovery Wizard PRO (step 1)

Wait for EaseUS Data Recovery Wizard Pro 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 hundreds 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: Scanning the storage drive with EaseUS Data Recovery Wizard PRO (step 2)

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. Note also that the trial version of EaseUS Data Recovery Wizard Pro is only capable of scanning drives and listing recoverable files - to restore them, you must purchase a license: Recovering data with EaseUS Data Recovery Wizard Pro

Step 3: Save the scan session (optional).

We recommend that you save the scanning session once you have completed recovery, in case you decide to recover additional files later. Simply click the "Save Scan Session" icon in the upper-right corner of the screen and choose the location for the file to be saved. This will save a lot of time, since you will not need to re-scan the storage drive the next time you wish to restore something. Bear in mind, however, that data removed after the scanning session has finished will not be listed: Saving scan session in EaseUS Data Recovery Wizard Pro

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 necessary information on Microsoft's documentation web page.

Data backups: The most reliable backup method 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 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. Therefore, you should consider using an application to create data backups locally.

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EaseUS Todo Backup

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We recommend using the EaseUS Todo Backup application. The "Home" edition of EaseUS Todo Backup is usually more than adequate for regular users, however, the "Business" edition is more suitable for companies and large computer networks. The EaseUS Todo Backup application provides extensive data protection features. You can easily create backups, and encrypt and compress them for enhanced protection and storage saving purposes. It also allows you to set backup schedules, create bootable devices, and restore the system if a crash occurs. You can easily choose where to store the created backup: locally; uploaded to an external drive; FTP; cloud storage, or elsewhere. In summary, EaseUS Todo Backup is an all-in-one tool, which provides all features required to properly backup your data.

Creating a data backup:

The backup process is virtually identical regardless of the item (file, partition, entire system) you wish to backup. Taking the File Backup feature as an example:

Step 1: Choose which item to backup.

Click on the "Menu" icon in the upper-left corner of the screen to reveal the menu and select "File Backup": Creating data backups with EaseUS Todo Backup tool (step 1)

Select the files you want to backup. You can also enter a name and description of the backup that will be created: Creating data backups with EaseUS Todo Backup tool (step 2)

Step 2: Change the default settings.

The EaseUS Todo Backup application provides a variety of additional options that can be added/modified while creating the backup. For example, you can encrypt data (add a password), select the compression rate (how much the backup should be compressed), performance (how many system resources should be allocated), add an email notification (you receive an email once the process is complete) and so on.

To open the options window, click the "Backup options" button in the lower-left corner of the screen: Creating data backups with EaseUS Todo Backup tool (step 3)

Select the settings you want to change and click "Save". You can also reset your changes by clicking "Reset to initial settings": Creating data backups with EaseUS Todo Backup tool (step 4)

Step 3: Select the backup destination.

As mentioned above, EaseUS Todo Backup allows you to choose where backups are saved - locally or externally.

Click the "Browse..." button and select the location you want the backup to be saved: Creating data backups with EaseUS Todo Backup tool (step 5)

Step 4: Safety measures and process completion.

Depending on the location you have chosen, there are a number of measures you should or should not take. If you are uploading to an internet-connected location (for example, Cloud storage, FTP, etc.), be sure to maintain your internet connection, otherwise you will have to start again. The same applies to external storage devices - do not unplug them until the process is complete.

The progress bar displays estimated time remaining until completion. Large backups (hundreds of gigabytes) can take hours to create (depending on storage device speed, internet connection, etc.). Therefore, the application also allows you to optionally choose what the system should do (shut down, sleep or hibernate) once the process has finished: Creating data backups with EaseUS Todo Backup tool (step 6)

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

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
CMG virus QR code
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