The Teza virus, also known as a ransomware infection, is part of the STOP family. This malware is famous for its malicious file encryption capabilities. Once the Teza virus gets into a system, it targets various types of files, such as documents, videos, photos, and more. It modifies the file structure and appends the “.teza” extension to each file, making them unusable without the decryption key.
Teza Virus Overview
Teza
🤔 Teza malware can be classified as ransomware that belongs to the DJVU/STOP family. Its main target is to encrypt files that are important to you. Then, this ransomware asks its victims to pay the ransom – ($490 – $980) in Bitcoin.
The Teza virus is a malware type that ciphers your files and forces you to pay for their decryption. This malware ciphers various file types. Encrypted files become identifiable by a distinct “.teza” extension. The affected files become inaccessible and unusable.
Subsequently, the ransomware asks for a file decryption payment in Bitcoin from its victims, ranging from $490 to $980. Usually, a text file with ransom payment guidances is named as “_readme.txt“.
Teza Ransomware uses Salsa20 encryption algorithms to cipher the targeted files. Since Teza virus utilizes such a robust encryption method, it becomes incredibly hard, if even possible, to pick the decryption key without cooperating with the attackers.
Once the files are encrypted, the Teza virus displays a ransom note to the victim, asking for a ransom payment for the decryption key. The ransom note provides instructions on how to pay off the bill and also often includes threats of data loss or increased ransom amounts if the demands are not met within a specified timeframe.
I have created a comprehensive list of potential solutions, advice, and practices to disable the Teza ransomware and recover your files. There are situations where you can regain access to the files, but sometimes, it may be impossible.
📌 Important Reminder!
It is essential to say that paying off the ransom is not a guarantee of the successful files recovery. The individuals who stand behind the Teza virus are known for their untrustworthiness. There were the cases where people have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Teza uses a unique key for every victim, with one exception:
The Teza virus is similar to other DJVU ransomware samples like Nzqw, Nzer, Nzoq, and Nztt. This virus encrypts a wide range of common file types and appends its distinct “.teza” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.teza” and “2.png” to “2.png.teza“.
Upon successful encryption, malware creates a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It as well adds this file to the desktop, so the victim will not miss the attack even without opening folders.
The image below provides a visual representation of files with the “teza” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Teza Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .teza |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | MSIL/Filecoder.AFS, Trojan:Win32/Amadey.MZZ!MTB, Win32/Filecoder.Conti.L |
| 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 terrifying notification demanding users to pay off the ransom to decrypt the encrypted data contains these frustrating warnings.
Teza ransomware arrives as a set of tasks that are needed to perform different tasks on a victim’s computer. One of the initial ones being launched is winupdate.exe, a tricky process that shows a fake Windows update pop-up during the attack. That is needed to convince the victim that a sudden computer slowdown is caused by a Windows update.
At the same time, the ransomware runs another process (which name commonly consists of 4 random characters) which commences scanning the computer for target files and encrypting them. Then the ransomware deletes Volume Shadow Copies from the system through the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once removed, it becomes virtually impossible to recover the previous computer state using System Restore Points. The problem 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 hackers modify the Windows HOSTS file by including a list of domains to it and mapping them to the localhost IP. As a result, the victim will see a DNS_PROBE_FINISHED_NXDOMAIN error when trying to open one of the blocked websites.
It has come to our attention that ransomware endeavors to restrict websites that promote various how-to guides for computer users. It is evident that by restricting specific domains, the crooks are attempting to prevent the victim from reaching relevant and helpful ransomware-attack-related information online. The virus also saves two .txt files on the victim’s computer that provide attack-related details – the victim’s public key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.
After all these changes, the malware doesn’t stop. Variants of STOP/DJVU are inclined to install Vidar password-stealing Trojan on compromised systems. This threat possesses an extensive 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 possibility to get your files back without paying the ransom are quite low. Thing is, the key is unique for each victim, and picking it will take exceptionally big amount of time.
Obtaining the online decryption key in another way is also merely impossible. It is kept on a remote server controlled by the hackers who spread the Teza infection. For receiving decryption key the payment should be $980. To obtain the payment details, the victims should contact the fraudsters 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
Do not pay the ransom!
Please, try to use the available backups, or Decrypter tool
_readme.txt file also requests that the system owner must get in touch with the hackers within 72 hours after the attack. If the 72hrs demand is met, hackers grant a 50% off. Thus the ransom amount will be minimized down to $490.
Yet, stay away from paying the ransom! I highly recommend that you do not contact these frauds and do not pay. An efficient solution to recover the lost data is just using the available backups, or using Decrypter tool from Emsisoft.
The peculiarity of all such viruses is the utilization a similar set of actions for decryption key generation. Thus, unless the ransomware is still under the stage of development or possesses with some hard-to-track encryption, manual data recovery is a thing you can’t perform. The exclusive resolution to prevent the loss of your valuable data is to regularly make backups of your crucial files.
Keep in mind that even if you do preserve such backups regularly, they must be stored into a specific location without loitering, not being connected to your main workstation. For instance, the backup may be kept on the USB flash drive or some optional external hard drive storage. Optionally, you may rely to the help of online (cloud) information storage.
It goes without saying, when you store your backup data on your common device, it may be ciphered together with other data. For this reason, placing the backup on your main computer is surely 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.
- Using online free hosting resources as a means to distribute the virus undetected.
- Disguising the virus installer alongside various apps, particularly those offered as freeware or shareware.
- Spreading the virus through spam emails containing deceptive links that lead to its installation.
- Obtaining pirated software from illegal peer-to-peer (P2P) resources, exposing users to potential malware threats.
Instances have been reported when the Teza virus was disguised as a legit thing, for example, the messages demanding to start a browser update or a vastly needed codec for online media playback. This is commonly the way how some online frauds aim to force you into install the ransomware manually, by actually making you directly participate in this process.
Surely, the bogus update alert will not tell that you are going to actually inject the virus. This process will be disguised under some alert stating that you should install an urgent security update or some questionable program whatsoever.
Without a doubt, the cracked apps represent the threat too. Using P2P is both illegal and may result in the injection of severe malware, including the Teza ransomware.
To sum up, what can you do to prevent the penetration of the ransomware into your computer? Even though there is no 100% guarantee to stop your PC from getting infected, there are some tips I want to give you to avert the Teza penetration. You must be careful while setting up free software today.
Make sure you always read what the installation window offers aside from the main free program. Stay away from opening suspicious email attachments. Do not open files from the unknown recipients. Naturally, your current security program must always be updated.
The malware does not show itself openly. It will not appear in the list of your available programs. However, it will be masked under some malevolent process running consistently in the background, that starts at the moment when you boot up your computer.
How To Remove Ransomware?
Video Guide
How To Decrypt .teza Files?
How to restore big files?
Try deleting .teza extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus accessed and did not encrypt the file, or it bugged and did not add the filemarker. If you have files that are very large (2GB+), the latter is most likely. Please, text me in the comments whether this helped you or not.
The newest extensions released around the end of August 2019 after the criminals made changes. This includes Nzqw, Nzer, Nzoq etc.
As a result of the changes made by the criminals, STOPDecrypter is no longer supported. 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 automatically choose the accessible directories in order to decode the currently accessible drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the help of the “Add” button.
Decryptors generally offer several options considering the specific malware family. The existing possible options are displayed in the Options tab and can be enabled or deactivated there. You may discover a detailed 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]
✓ 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.
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
How to Restore .teza Files?
In some case ransomware is not doom for your files…
The Teza ransomware encryption mechanism feature is next: it ciphers every file byte-by-byte, then saves a file copy, deleting (not overriding!) the original file. Hence, the data of the file location on the physical disk is lost, but the original file is not deleted from the disk. The cell, or the sector where this file was stored, can still contain this file, but it is not present in the file system and can be rewritten by data that has been loaded to this drive after the deletion. 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 open-source program, which is originally created for file retrieval from damaged disks, or for files recovery in case if they are unintentionally deleted. However, with time flow, this program adopted the ability to restore the files of 400 different formats. Hence, it can be used for data recovery after the Teza attack.
First, you need to download this app. It is 100% free, but the developer notifies that there is no warranty that your files will be restored. PhotoRec is spread together with another program of the same developer – TestDisk. The downloaded archive will bear 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 setup is needed – 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 Teza ransomware.
Upon the start, you will observe the screen showing you the full list of your disks. However, this details are presumably useless, because the required menu is placed a bit higher. Click this tab, then choose the disk which was attacked by ransomware.
After opting for 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 designate the file formats. This feature is located at the bottom, too. As it was mentioned, PhotoRec can recover the files of about 400 different formats.
Finally, you can begin files restoration by pressing the “Search” button. You will view the screen where the findings of the scan and recovery are shown.
Teza files recovery Video Guide.
Frequently Asked Questions
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