Oohu Virus Ransomware (.oohu File)

Oohu 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 $490 to $980 in Bitcoins for the decryption key.

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About Oohu Ransomware:


NameOohu Virus
Version0784
File Extension.oohu
Contact[email protected], [email protected]
FamilySTOP/Djvu Ransomware
Note_readme.txt
Offline IDdhL6XvokZotUzL67Na5WfNIBufODsob7eYc3mzt1
Last seenSeptember 18, 2023
AlgorithmSalsa20 encryption. If Oohu 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 .oohu files in the future.
RansomFrom $490 to $980 (in Bitcoins)
Damage
  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----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAx5BqeWGwHmcgjbaAsjpD e0AigrNBuYmLeDVLdZ2BSdUhga7JxmwSkPWdR7uDfOKDwKLU2vv7mTJJVikE+ED0 eCw+Q//sV4bVB9qDUObno0M1HcM5y3YFJAeuCt85e3JQQnYQHhN6mlCPFd1vVZAn C2XeDNWQ5XcJwp8lRV2k4s0CONrM2rH909N5+Yj7RahvCKAzzEbUhW6VFZK9j3oA 5eLARM40VO2pZLPkUYGcjGvY+DiUmScoa10O46NlMaCqEQUM58dMHqpifpYcVrOD o+076RFizmwG6CL3BZR+1Tt8CcC1WHyfam0v1m2QTRSuVD0RQFlV4/ZCNcBupGin 4wIDAQAB -----END PUBLIC KEY-----
Other variants
  • Oopl Ransomware (.oopl encrypted files)
  • Hgml Ransomware (.hgml encrypted files)
  • Hgew Ransomware (.hgew encrypted files)
  • Oohu Virus Ransomware (.oohu) File - How does it work?

    What is Oohu ransomware?

    Oohu ransomware is always a thing that is better to avoid. This virus harms too much, not only your files but also your wallet. Moreover, it also breaks into your computer’s configurations and weakens your system. Thus, it is better to prevent its appearance than to think about how to deal with the consequences of its activity.

    Almost all cases of Oohu virus injection are related to the use of “free” programs. These apps are about to be purchased, but hackers remove the license checking to be launched and used without any payments. While dealing with license checking, hackers can easily add malware to the program code. Which one - depends only on how much they are paid for this. Oohu ransomware is another example of such a virus.

    Salsa20 is the encryption algorithm used by this virus for file encryption. It is not the strongest among the existing ones, but its strength is heavily increased by the key stored on the remote server. Since ransomware maintainers control servers, there is no way to get vital besides paying the ransom. Brute force is useless because of the vast number of possible keys (>1*10^78). File decryption tools may give you a chance, but the opportunity to get your files back is low.

    Encryption process

    The Oohu 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 - ".oohu". Then, ransomware creates a _readme.txt file in the folder where the encrypted file is located, and goes to the next folder.

    .OOHU 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 Oohu 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:

    ATTENTION!

    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:
    https://we.tl/t-XA1LckrLRP
    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.


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

    Indicators of Compromise(IOC)

    File NameMD5File Size
    📜 SAMPLE.EXEd246b71e5df1eb4c2a7e617404aee3d4200704
    📜 SAMPLE.EXE49d8743b2ca1a7b66775d58fbf1945da200704
    📜 SAMPLE.EXEc2273e3679c0660d8b4cd294ec6f88a7713216
    📜 SAMPLE.EXE78c7387aa5096d01a416ef5eaac0a2151273856