OOHU Virus (.OOHU File) 🔐 Decrypt & Removal Guide

The Oohu virus, also known as a ransomware infection, belongs to the STOP family. This malware is notorious for malicious file ciphering. Once the Oohu virus infects a computer, it targets various types of files, like documents, videos, photos, and more. It changes the file structure and adds the “.oohu” extension to each encrypted file, making them unusable without the decryption key.

Oohu Virus Overview

The Oohu virus is malware that encrypts your files and makes you pay for their recovery. This malware ciphers various file types. ciphered files are identifiable by a distinct “.oohu” extension. As a result, the files touched by ransomware become impossible to access and use.

Subsequently, the ransomware asks for a file decryption payment in Bitcoin from its victims, ranging from $490 to $980. Usually, a ransom text file is named as “_readme.txt“.

Oohu Ransomware uses Salsa20 encryption algorithms to cipher the files. Since Oohu virus uses such a strong encryption method, it becomes quite hard, if not impossible, to find the decryption key without the assistance of the attackers.

Once Oohu malware finishes the encryption, it shows a ransom note to the user, demanding a ransom payment for the decryption key. The ransom note contains instructions on how to make the payment and often includes threats of permanent data loss or ransom amounts surge if the ransom is not paid within a specified timeframe.

I have created a comprehensive list of potential solutions, advice, and approaches to remove the Oohu malware and decrypt and recover your files. In some cases, you can recover the files, but sometimes, it may be impossible.

Oohu uses a unique key for each victim, with one exception:

The Oohu virus is highly similar to other DJVU ransomware variants like Oopl, Ooza, Hgew, and Hgfu. This virus encrypts a wide range of common file types and appends its distinct “.oohu” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.oohu” and “2.png” to “2.png.oohu“.

After successful encryption, malware spawns 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 its appearance even without opening folders.

The image below provides a visual representation of files with the “oohu” extension:

Encrypted Files by STOP/DJVU Ransomware

This message asking payment is for restore files via decryption key:

_readme.txt (STOP/DJVU Ransomware) – The frightening alert requesting users to pay the ransom to decrypt the encrypted data contains these frustrating admonitions.

Oohu ransomware carries out a set of operations to perform certain activities on a victim’s computer. It initially launches a deceptive process called winupdate.exe, which displays a fraudulent Windows update alert during the attack. This trick convinces the victim that their PC has slowed down due to a Windows update.

Simultaneously, the ransomware initiates another process (named as 4 random characters) that scans the disk for target files and encrypts them. The ransomware then removes Volume Shadow Copies from the system using the following CMD command:

vssadmin.exe Delete Shadows /All /Quiet

Once removed, it becomes impossible to restore the previous computer state using System Restore Points. The problem is that ransomware operators eliminate any built-in Windows methods that could help the victim recover files for free. Additionally, the crooks modify the Windows HOSTS file by appending a list of domains to it and redirecting them to the localhost IP. Consequently, the victim encounters a DNS_PROBE_FINISHED_NXDOMAIN error when trying to access one of the listed websites.

We observed that the ransomware attempts to block websites that publish various how-to guides for computer users. It is evident that by restricting specific domains, the malefactors aim to hinder the victim’s access to relevant and helpful ransomware-attack-related information online. This malware also saves two text files on the victim’s computer, which contain attack-related details – the victim’s public key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.

After making these alterations, the malware does not stop. Variants of STOP/DJVU tend to release the Vidar password-stealing Trojan on compromised systems. This threat possesses a wide range of capabilities, including:

• Gathering sensitive data by running malicious software on the victim’s computer.
• Acquiring unauthorized login credentials for Steam, Telegram, and Skype accounts.
• 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 used by STOP/Djvu ransomware is AES-256. Therefore, if your data gets encrypted with an online decryption key, the chances of recovering your files are quite low. The online key is unique for each victim, and finding a suitable one would require an exceptionally significant amount of time.

Obtaining the online decryption key in any other way is also nearly impossible. It is stored on a server owned by the criminals who spread the Oohu infection. To receive the decryption key, victims must make a payment of $980. For payment details, victims should contact the fraudsters via email at ([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

Do not pay the ransom!

Please, try to use the available backups, or Decrypter tool

The _readme.txt file also requires the computer user to contact the hackers within 72 hours from the moment the files were encrypted. If you meet the 72-hour demand, the hackers will grant a 50% discount, reducing the ransom amount to $490.

However, I highly recommend that you stay away from paying the ransom! Do not contact these frauds and do not make the payment. You can effectively retrieve the lost data by using the backups you have or by using the Decrypter tool from Emsisoft.

The peculiarity of such malware is that it employs a similar set of actions to generate the unique decryption key needed to recover the encrypted data. Thus, unless the ransomware is still in the development stage or exhibits some hard-to-track encryption, you cannot perform manual data recovery. The exclusive solution to prevent data loss is to regularly back up your important files.

Remember that even if you maintain such backups regularly, you should store them in a specific location separate from your main workstation. For instance, you can keep the backup on a USB flash drive or some other external hard drive storage. Alternatively, you can rely on online (cloud) information storage for backup.

It’s unnecessary to mention that if you keep your backup data on your common device, it may become encrypted along with other data. For this reason, storing the backup on your computer’s disk is certainly not a wise idea.

How I was infected?

Ransomware has a various methods to built into your system. But it doesn’t really matter what way had place in your case.

Ransomware attack following a successful phishing attempt.

How To Remove Ransomware?

Video Guide

How To Decrypt .oohu Files?

The newest extensions released around the end of August 2019 after the criminals made changes. This includes Oopl, Ooza, Hgew etc.

As a result of the alterations 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.

1. Select folders for decryption.

   Based on the default configurations, the decryptor will by default choose the available directories in order to decode the currently available drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the aid of the “Add” button.

   Decryptors generally propose several options depending on the specific malware family. The present possible options are displayed in the Options tab and can be turned on or turned off there. You may find a comprehensive list of the currently active Options below.

2. 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]

✓ No key for New Variant online ID: [your ID]

Notice: this ID appears to be an online ID, decryption is impossible

✓ Result: No key for new variant offline ID: [example ID]

This ID appears be an offline ID. Decryption may be possible in the future.

✓ Remote name could not be resolved

How to Restore .oohu Files?

In some case ransomware is not doom for your files…

The Oohu ransomware encryption mechanism feature is next: it ciphers every file byte-by-byte, then saves a duplicate, removing (not overriding!) the original file. Thus, the information of the file placement on the disk drive is lost, but the original file is not deleted from the disk. The cell, or the sector where this file was kept, can still hold this file, but it is absent in the file system and can be rewritten by data that has been loaded to this disk after the removal. Hence, it is possible to retrieve your files using special software.

Recovering your files with PhotoRec

PhotoRec is an free program, which is originally created for data recovery from damaged disks, or for files recovery in case if they are unintentionally deleted. However, as time has gone by, this program received the ability to retrieve the files of 400 different extensions. Hence, it can be used for file recovery after the Oohu attack.

First, you need to download this app. It is 100% free, but the developer notifies that there is no warranty that the files will be retrieved. PhotoRec is spread in a pack with another utility of the same developer – TestDisk. The downloaded archive will bear TestDisk name, but don’t worry. PhotoRec files are right inside.

To open PhotoRec, find and open “qphotorec_win.exe” file. No installation process is required – this program has all the files it need inside of the archive, hence, you can mount it on your USB drive, and help your friends/parents/anyone who has been attacked by Oohu ransomware.

After the launch, you will observe the screen showing you the full list of your disk drives. However, this details are probably useless, 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 choose the destination folder for the reclaimed files. This menu is located at the lower part of the PhotoRec window. The best selection is to export them on USB drive or any other type of removable disk.

Then, you need to specify 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 view the screen where the results of the scan and recovery are shown.

Oohu files recovery Video Guide.

Frequently Asked Questions

1. My files are encrypted by ransomware, what should I do now?
2. About DJVU (STOP) Ransomware.

German Japanese Spanish Portuguese (Brazil) French Turkish Chinese (Traditional) Korean Indonesian Hindi Italian