The Cdmx virus, also known as a ransomware infection, belongs to the STOP/DJVU family. This malware family is famous for file encryption and extortion. Once the Cdmx virus infects a computer system, it scans the system for files such as documents, videos, photos, and more. It changes the file structure and appends the “.cdmx” extension to each file, making them unusable without the decryptor.
Cdmx Virus Overview
Cdmx
🤔 Cdmx virus is ransomware that belongs to the DJVU/STOP ransomware family. Its main target is to cipher your files. Then, the ransomware virus asks its victims for a ransom payment – ($490 – $980) in Bitcoin.
The Cdmx virus is a malware type that ciphers your files and coerces you into paying for their recovery. This ransomware encrypts various file types. ciphered files are identifiable by a distinct “.cdmx” extension. The files touched by ransomware become inaccessible and unusable.
Subsequently, the ransomware asks for a file decryption payment in Bitcoin from the victims, which ranges from $490 to $980, depending on the time passed after the attack. Typically, a text file with ransom payment guidances is named “_readme.txt“.
Cdmx Ransomware operates by Salsa20 encryption algorithms to scramble the contents of the targeted files. Since Cdmx virus utilizes such a robust ciphering method, it becomes quite difficult, if not impossible, to pick the decryption key without cooperating with the attackers.
Once the files are encrypted, the Cdmx virus displays a ransom note to the user, demanding a ransom payment in exchange for the decryption key. The ransom note contains instructions on how to pay off the bill and also often includes threats of system wipeout or increased ransom amounts if the demands are not met within a specified timeframe.
I have made a comprehensive list of the solutions, advice, and approaches to disable the Cdmx ransomware and decrypt and recover your files. In some cases, it may be feasible to restore your files, while sometimes, it may be impossible.
📌 Important Reminder!
It is crucial to say that paying the ransom does not guarantee the successful files recovery. The rascals who stand behind the Cdmx virus are known for their untrustworthiness. There have been instances where victims have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Cdmx uses a unique key for each victim, with one exception:
The Cdmx virus is highly similar to other DJVU ransomware variants like Cdqw, Lomx, Loqw, and Cdxx. This virus encrypts a wide range of common file types and appends its distinct “.cdmx” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.cdmx” and “2.png” to “2.png.cdmx“.
Upon successful encryption, the virus creates a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It also adds the readme file to the desktop, so the user will not miss the attack even without opening folders.
The image below provides a visual representation of files with the “cdmx” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Cdmx Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .cdmx |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Hoax.FakeRansom, Trojan:Win32/Aenjaris!pz, Win32/Filecoder.Avaddon.H |
| Symptoms |
|
| Fix Tool |
To remove possible malware infections, scan your PC:
6-day free trial available. |
This message asking payment is for restore files via decryption key:
_readme.txt (STOP/DJVU Ransomware) – The frightening alert demanding users to pay the ransom to decrypt the encrypted data contains these frustrating admonitions.
Cdmx ransomware arrives as a set of tasks that are used to perform different activities on a victim’s computer. One of the initial processes being launched is winupdate.exe, a sneaky process that displays a fraudulent Windows update prompt during the attack. Such a trick helps to convince the victim that their PC has become slow because of a Windows update.
Simultaneously, the ransomware runs another process (usually named by four random characters) which commences scanning the computer for target files and encrypting them. Next, the ransomware removes Volume Shadow Copies from the disk using the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once deleted, it becomes nearly impossible to recover the previous computer state using System Restore Points. The concern is, ransomware operators are getting rid of any built-in Windows methods that could assist the victim to regain files for free. In addition, the rascals modify the Windows HOSTS file by appending a list of domains to it and linking them to the localhost IP. As a result, the victim will witness a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the blacklisted websites.
It has come to our attention that ransomware tries to restrict websites that promote various how-to guides for computer users. It is evident that by limiting specific domains, the malefactors are attempting to stop the victim from accessing relevant and helpful ransomware-attack-related information online. The virus also stores two .txt files on the victim’s computer that provide attack-related particulars – the victim’s public key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.
After all these modifications, the malware doesn’t halt. Variants of STOP/DJVU tend to release Vidar password-stealing Trojan on compromised systems. This threat has an large list of capabilities, including:
- Infiltrating the victim’s computer with malware and executing it to gain unauthorized access.
- Obtaining unauthorized access to login credentials of Steam, Telegram, and Skype.
- Manipulating and viewing files on the victim’s computer without their knowledge.
- Stealing cryptocurrency wallets from the victim’s system.
- Granting the hackers remote control over the victim’s computer for various malicious activities.
- Extracting sensitive information such as browser cookies, saved passwords, and browsing history.
The cryptography algorithm in STOP/Djvu ransomware is AES-256. So, if your data got encrypted with an online decryption key, the chances to get your files back without paying the ransom are quite low. Thing is, the key is unique for each victim, and finding a suitable one will take too much time.
Retrieving the online key in another way is also merely impossible. It is stored on a command server controlled by the criminals who promote the Cdmx malware. For receiving decrypting code the payment should be $980. To get the payment details, the victims should contact the hackers by email ([email protected]).
The message by the ransomware states the following information:
ATTENTION! Don't worry, you can return all your files! All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key. The only method of recovering files is to purchase decrypt tool and unique key for you. This software will decrypt all your encrypted files. What guarantees you have? You can send one of your encrypted file from your PC and we decrypt it for free. But we can decrypt only 1 file for free. File must not contain valuable information. You can get and look video overview decrypt tool: https://we.tl/t-WJa63R98Ku Price of private key and decrypt software is $980. Discount 50% available if you contact us first 72 hours, that's price for you is $490. Please note that you'll never restore your data without payment. Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours. To get this software you need write on our e-mail: [email protected] Reserve e-mail address to contact us: [email protected] Your personal ID: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
How To Remove STOP/Djvu Ransomware?
Video Guide
How To Decrypt .cdmx Files?
How to restore big files?
Try deleting .cdmx extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus accessed and did not encode the file, or it failed and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. Please, let me know in comments if that will work for you.
The newest extensions released around the end of August 2019 after the criminals made changes. This includes Cdqw, Lomx, Loqw etc.
As a outcome of the changes made by the criminals, STOPDecrypter is no longer backed. It has been replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft.
You can download free decryption tool here: Decryptor for STOP Djvu.
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Select folders for decryption.
Based on the default configurations, the decryptor will by default choose the accessible directories in order to decode the currently reachable drives (the connected ones), including the network drives. Additional (optional) locations can be selected with the aid of the “Add” button.
Decryptors usually offer several options considering the specific malware family. The present possible options are displayed in the Options tab and can be turned on or disabled there. You may find a comprehensive list of the currently active Options below.
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Click on the “Decrypt” button.
As soon as you add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.
Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:
The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.
The Emsisoft Decryptor might display different messages after a failed attempt to restore your files:
✓ Error: Unable to decrypt file with ID: [your ID]
Emsisoft failed to find a correspondnig decryption key in their database.
✓ No key for New Variant online ID: [your ID]
Notice: this ID appears to be an online ID, decryption is impossible
Your original files were encrypted with an online key. There is no one to share the decryption key with you. File recovery is only possible through paying the ransom. 🙁
✓ Result: No key for new variant offline ID: [example ID]
This ID appears be an offline ID. Decryption may be possible in the future.
Malware used an offline key, though the file recovery operation failed (the offline decryption key isn’t available yet). But, receiving this message is good news for you, because it might be possible to restore your files in the future. 🙂
It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.
✓ Remote name could not be resolved
It’s an indication of a DNS issue on your PC. Consider resetting your HOSTS file to default.
How to Restore .cdmx Files?
In some case ransomware is not doom for your files…
The Cdmx ransomware encryption mechanism is next: it encodes every file byte-by-byte, then saves a file copy, erasing (not overriding!) the initial file. Thus, the information of the file location on the disk drive is lost, but the original file is not removed from the physical disk. The cell, or the sector where this file was stored, can still contain this file, but it is absent in the file system and can be overwritten by data that has been loaded to this disk after the removal. Hence, it is possible to restore your files using special software.
Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected, or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage.
When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data.
As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I was transferring some files from my backup.
Hopefully, this can help some other people in my situation.
Jamie NewlandRecovering your files with PhotoRec
PhotoRec is an free open-source program, which is originally created for files recovery from damaged disks, or for files recovery in case if they are unintentionally deleted. However, as time has gone by, this program got the ability to retrieve the files of 400 different file types. Hence, it can be used for data recovery after the Cdmx attack.
First, you need to download this app. It is 100% free, but the developer notifies that there is no assurance that the files will be recovered. PhotoRec is distributed in a pack with other utility of the same developer – TestDisk. The program archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.
To run PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation process is needed – this program has all the files it need within the archive, hence, you can fit it on your USB drive, and help your friends/parents/anyone who has been attacked by Cdmx ransomware.
Upon the start, you will observe the screen showing you the full list of your disk drives. However, this information is probably irrelevand, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.
After choosing the disk, you need to opt for the destination folder for the retrieved files. This menu is located at the lower part of the PhotoRec window. The best choice is to export them on USB drive or any other type of removable disk.
Then, you need to designate the file formats. This choice is located at the bottom, too. As it was mentioned, PhotoRec can restore the files of about 400 different formats.
Finally, you can start files restoration by pressing the “Search” button. You will see the screen where the results of the scan and recovery are shown.
Cdmx files recovery Video Guide.
Frequently Asked Questions
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