Cdxx Virus Ransomware (.cdxx File)

Cdxx Virus is a strain within the STOP/Djvu Ransomware family, employing the Salsa20 encryption algorithm to encrypt files on compromised systems. Victims are coerced into paying a ransom ranging from $4999 to $9999 in Bitcoins for the decryption key.

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About Cdxx Ransomware:

NameCdxx Virus
File Extension.cdxx
Contact[email protected], [email protected]
FamilySTOP/Djvu Ransomware
Offline IDLBxKKiegnAy53rpqH3Pj2j46vwldiEt9kqHSuMt1
Last seenFebruary 05, 2024
AlgorithmSalsa20 encryption. If Cdxx cannot establish a connection to crooks server before starting the encryption process, it uses the offline key. This key is the same for all victims(!), making it possible to decrypt .cdxx files in the future.
RansomFrom $4999 to $9999 (in Bitcoins)
  1. ⮞ Can delete Volume Shadow copies to make victim’s attempts to restore data impossible;
  2. ⮞ Adds a list of domains to HOSTS file to block access to certain security-related sites;
  3. ⮞ Installs password-stealing trojan virus, like Redline Stealer, Vidar Stealer, Smokeloader, Azorult and others;
DistributionThird-party downloaders, installers, peer-to-peer networks, RDP exploits, etc.,
RSA Public Key-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvzp5nTauroRB2mdPciqz v7PG5h3E/jLQaM7+1aOAgKgJcGMT7x5f+e+IdUOffKhUVwElIRUiAZqsOU4kA08R 4ZTxreglZzls5RTA925ibjmikqGZnVbbB89mdlw2C9XlQpHhcop/zJhfkguVVReo 4J2FFdamvr9AZdRjFj736hQCvKRBHALe5PmHw9uiCA/VWnabwfQ3hrLUqSJY5PfE dCQTFBBgPbSDhnjCWp++uurs4u28GnCXty4Z5HWqPDe/4DKlplE1PN+znewoexnB 5DLWYZ+HHRf8YAkHgrWIAx6GV9ZqiBO+rmNdO7uQNvuvqi4ktoMk69UFY/Qi0BfT cwIDAQAB -----END PUBLIC KEY-----
Other variants
  • Cdcc Ransomware (.cdcc encrypted files)
  • Cdtt Ransomware (.cdtt encrypted files)
  • Cdpo Ransomware (.cdpo encrypted files)
  • Cdxx Virus Ransomware (.cdxx) File - How does it work?

    What is Cdxx ransomware?

    Seeing that your files have .cdxx extension and _readme.txt files in various folders mean that you are infected with Cdxx ransomware. This sort of malware is created to extort money from the users, previously encrypting the files on its PC. It is likely impossible to decrypt the files without special software.

    Cdxx virus and any other member of the STOP/Djvu family use the Salsa20 encryption mechanism. This cipher has an enormous amount of possible decryption keys, so it is impossible to brute force them, for example. Even with quantum computers, you will likely spend more time than our planet will approximately exist. But don’t worry - using specific applications designed especially for file decryption purposes, you may get your files back in just several hours.

    The main ways of Cdxx ransomware distribution are third-party websites that offer the users to get some programs for free or use different dubious tools. Hackers who break the license checking procedure in programs (this action allows them to use the program without any payments) inject malicious code, or even the whole virus, into their “products”. Malware developers pay such people.

    Dubious tools are even easier to use for that purpose. Usually, they are created for outlaw actions, like generating the license keys for specific programs or activating Windows without any payments. Antivirus programs detect all such apps, so crooks always instruct you to disable your security tool or add the hack tool to the allowlist. Unfortunately, you will not understand what happens until it is too late.

    Encryption process

    The Cdxx ransomware uses the Salsa20 encryption algorithm. That is not the strongest method, but it still provides an overwhelming amount of possible decryption keys. To brute force the 78-digit number of keys, you need 3.5 unvigintillion years (1*10^65), even if you use the most powerful regular PC. Quantum computers can show a bit better results, but it is still too slow to get your files back while you are alive.

    The exact algorithm of encryption is next: malware scans each folder for the files it is able to encrypt. Then, when it finds the target, it makes a copy of your file, removes the original one, encrypts the copy and leaves it instead of the removed original. Such a procedure is done to prevent the situation when you have already opened the file, so ransomware is not able to read it because of the Windows restrictions. To each encrypted copy, the virus adds the specific extension - ".cdxx". Then, ransomware creates a _readme.txt file in the folder where the encrypted file is located, and goes to the next folder.

    .CDXX Files

    Such an encryption method can be exploited for file recovery. Since the original file is deleted, you may try to recover it using the file recovery tools. The less time is passed - the bigger the chance to get your files back, so hurry up!

    Another specific moment that can help you to use the files even after the encryption is the fact that Cdxx ransomware encrypts only the first 150KB of each file. Hence, you can try to run a big file, such as video or music, without the encryption. Similar feature also works with other ransomware families - Dharma, Conti and Makop encrypt the same 150KB.

    Ransom note: _readme.txt

    Ransom note is the same for the whole ransomware family. In fact, it is one of the main signs of to which family the certain ransomware belongs. Here is the typical note for STOP/Djvu family:


    Don't worry, you can return all your files!
    All your files like pictures, 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:
    Price of private key and decrypt software is $9999.
    Discount 50% available if you contact us first 72 hours, that's price for you is $4999.
    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]

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    🔗 HowToFix.Guide: How To Decrypt .cdxx Files?

    Indicators of Compromise(IOC)

    File NameMD5File Size
    📜 SAMPLE.EXE87ba288f14fbf826d4cf061d9f8e72ed767488
    📜 SAMPLE.EXEd1aa460d429d1a3a7354252293cb487f689664
    📜 SAMPLE.EXEd29a970d622c9ff06e6f89fc2a52110e9581609
    📜 SAMPLE.EXEdefd2b4b32a95284081f3fd648e78f2e696832
    📜 SAMPLE.EXE0b31fe7345c7d6f28989c516108d53e3641285
    📜 SAMPLE.EXE709dc9523c485bdba7b65944a010e56a6884078
    📜 SAMPLE.EXEd73567b918afe0081de4251aec9035d319233710