Geek's Advice

TUID is a ransomware-type virus that encrypts all files on a computer

TUID ransomware is a newly detected malicious and file-encrypting virus that recently emerged from the dangerous STOP/DJVU ransomware family. This virus functions by encrypting all files it can locate in any computer it infects and appends .tuid extension to all the filenames. E.g. a file that was hitherto saved as 1.jpg would automatically be renamed 1.jpg.tuid and so on. During the attack, ransom notes known as _readme.txt will also be dropped in all the folders. These are more or less notifications sent by the cybercriminals informing the victim about the development and why it is necessary for them to pay a certain amount of money as ransom in exchange for TUID decryption tool.

They will claim in the ransom note that TUID ransomware virus was able to encrypt every file contained in the infected computer, including vital documents, pictures, and various data using very strong and unique key. Therefore, the victim is left with no other choice than to pay ransom if they hope to have the encrypted files restored back to normal. To facilitate further discussions between them, two email addresses will also be dropped, namely: support@sysmail.ch and supportsys@airmail.cc.

In addition to that, pricing of the decryption tool will also be explained as well as the accompanying terms of payment. They will state that if the victim is able to pay within 72 hours of being notified, it will enable them to leverage a 50% discount offer. This means instead of paying the normal ransom fee of $980, they would now pay half of it which is $490, but once the “grace period” elapses, only the full payment would be acceptable.

It does not end there, once the victim reaches out to them, more conditions will be reeled out. They will emphasize that payment can only be made through cryptocurrency whereby the victim would have to purchase cryptocurrency that is equivalent to the ransom fee and also send it to a wallet address of their choice. The apparent reason why they avoid conventional payment method is to prevent law enforcement agents from coming after them. To provide the victim a proof of their expertise, they additionally suggest that one of the encrypted files can be sent to them for test decryption.

Regardless of the situation, our cybersecurity experts recommend that victims should follow the FBI’s directive in regards with ransom demand, and it unambiguously stated that RANSOM SHOULD NOT BE PAID. Paying ransom does not guarantee you will recover your lost data; on the contrary, you will only be enriching cybercriminals. It would also encourage them to continue in their criminal acts and even expand their capacity.

The virus is equally notorious for dropping certain information-stealing Trojans like VIDAR and AZORULT on the already infected computer. Such Trojans can surreptitiously steal sensitive information such as cryptocurrency wallets, banking details, software login credentials, passwords etc.

For those whose computers have been infected with any of the STOP/DJVU ransomware variants, particularly the one under review, it is crucial to remove TUID ransomware virus without delay. The recommended way of doing it is to first set up your computer in Safe Mode with Networking before running any genuine antivirus software on it. It is very important to ensure that the antivirus you’re using is reliable. Additionally, we recommend downloading RESTORO to restore damaged Windows OS files.

Ransomware Summary

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Ransomware distribution methods used by cybercriminals

The most common way computer systems become infected with variants of STOP/DJVU ransomware like TUID virus is when their users download software contents from online malicious torrents. Malware are often embedded in such pirated copies, including the so-called “cracks” and key generators. Therefore, trying to make use of such illegal contents can eventually result in severe virus infection. Over the years, there have been reports from several victims about how their computer systems became infected after they downloaded software contents from online torrent libraries. Listed below are some of the pirated software copies often used by cybercriminals in distributing ransomware:

• Adobe Photoshop;
• VMware Workstation;
• Tenorshare 4ukey;
• AutoCad;
• Opera browser;
• Corel Draw;
• Fifa 20;
• Cubase;
• Adobe Illustrator;
• League of Legends;
• KMSPico (illegal Windows activation tool).
• Internet Download Manager.

Computer users that tend to source their software needs from such dangerous platforms should desist from doing so now. Otherwise they risk facing dire consequences. Aside from the risks to your computer and the files contained in it, also note that unauthorized download and use of copyrighted software contents is against the law and thus you could be prosecuted accordingly. Instead of exposing yourself to all those risks, it is a lot better to obtain your software needs strictly from the official pages of the original content producers or their third-party agents. Also have it in mind that whatever price they charge can never be compared to the outrageous amounts cybercriminals usually demand as ransom fees.

Another prolific method used by cybercriminals in spreading malware is through malicious email attachments. In this case, they make use of files such as DOCX, XLS or PDF in crafting believable messages (they prefer these particular ones because they allow JavaScript and other macro functions) that can be attached with payloads that would be triggered when it is opened in any computer.

The worrisome aspect of it is the fact that it can be quite difficult trying to differentiate a malware-carrying email and from a genuine one. The reason is because cybercriminals go as far as impersonating others. Also, they would give the attachments compelling tags like Invoice, Tracking Details or Order Summary etc. Alternatively, they may even use email spoofing techniques to hide the actual address the email is emanating from. Therefore, it is very important not to open emails indiscriminately; instead you should be sure of its source before opening it.

Before we conclude, it is necessary to inform victims of STOP/DJVU ransomware to always avoid those websites that claim to provide decryption solutions because such hardly exist. So far, only tools from DiskTuna and Emsisoft have proven to be reliable. You can follow this link for more details about them.

Further details about the virus

This section dwells more about the technical aspect of the virus and what happens to your computer during TUID ransomware attack. The first thing this piece of malware does is launching build.exe or build2.exe as well as winupdate.exe. Once that is done, the ransomware will fetch a response from https[:]//api.2ip.ua/geo.json and saves the result in the geo.json file. This way, the virus gathers information about your computer, including the computer’s geolocation, time zone, zip code, longitude and latitude. Shown below is a screenshot of some geo.json file samples.

Other important details like the installed software list and hardware details would be processed into information.txt.

The malware will now profile the country code of wherever the computer is located against their list of encryption-protected countries (Russia, Syria, Belarus, Armenia, Tajikistan, Kazachstan, Kyrgyzstan, Ukraine and Uzbekistan). If it discovers that the computer is situated in any of these countries, it would instantly abort its mission. However, if not, the ransomware will now extract online encryption key from their server and then save it along victim’s ID in bowsakkdestx.txt file. The ID will be also separately saved into a file named PersonalID.txt file. Examples of the files are shown below.

In situations whereby the virus couldn’t get any online encryption key from their server, it will instead use a hardcoded offline key for autonomous functionality. You can decipher if an offline key was used if it has t1 characters appended to the victim’s personal ID. The implication of this is that your chances of decrypting .tuid just got brighter. Please check below for more details on this.

Full data encryption will now commence with the scanning of all folders as well as the encryption of files using Salsa20 before eventually using RSA-2048 in locking it. The virus also marks each encrypted file with an additional extension.

Shown in the image below is the _readme.txt ransom note left in all the folders.

To complete the circle, the malware will blacklist certain domains in Windows HOSTS file also map them on the localhost IP, thereby effectively blocking the victim from having access to them. Any attempt to browse them will bring up DNS_PROBE_FINISHED_NXDOMAIN error message. This is a cunning move by the cybercriminals in ensuring the victim doesn’t get any help from online support forums.

Remove TUID Ransomware Virus and Recover Lost Files

Victims of any type of ransomware, including the variant being discussed should endeavor to report the incident to any relevant government agency vested to handle such issues, and also remove TUID ransomware virus as quickly as possible. For more detailed action plan on what to do following a ransomware attack, please go through the steps outlined below. Meanwhile, remember that the best way to remove a virus from an infected computer is to boot such computer using Safe Mode with Networking option before making use of a strong antivirus software. You can also make use of (download link) in identifying and repairing Windows system files damaged by the virus.

Now that TUID ransomware virus has been removed, here are the steps to follow:

• Report the cyber-attack to relevant local authorities responsible for handling such issues.
• Make use of any available data backup device in restoring lost data. However, you should ensure the virus is completely removed before plugging any external device.
• Learn possible ways files damaged by STOP/DJVU ransomware variants can be repaired/decrypted.
• Change all passwords that were directly used on the compromised computer.

OUR GEEKS RECOMMEND

Our team recommends removing malware using a professional antivirus software and then using the following tool to repair virus damage to Windows system files:

REPAIR VIRUS DAMAGE TO YOUR COMPUTER

DOWNLOAD RESTORO

RESTORO provides a free scan that helps to identify hardware, security and stability issues and presents a comprehensive report which can help you to locate and fix detected issues manually. It is a great PC repair software to use after you remove malware with professional antivirus. The full version of software will fix detected issues and repair virus damage caused to your Windows OS files automatically.

RESTORO uses AVIRA scanning engine to detect existing spyware and malware. If any are found, the software will eliminate them.

Read full review here.

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Norbert Webb

Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.