Geek's Advice

AVYU is a new ransomware variant that seeks to encrypt your computer files

AVYU ransomware is the latest malicious file-encrypting malware to emerge from the STOP/DJVU ransomware family. This highly dangerous virus is notorious for encrypting every available it can find in any computer it infects while also appending .avyu extension to all the file names. E.g., a hitherto saved file called 1.jpg will be automatically renamed 1.avyu. Furthermore, while the cyber-attack continues, copies of notes called _readme.txt will get dropped in all the folders. These notes contain warnings from those behind the cyber-attack who explain what happened and why the victim needs to pay some money to receive the AVYU decryption tool.

They will emphasize that the entire files in the computer have been encrypted by AVYU ransomware virus (including important documents, pictures, and every other data), using a very strong and complex encryption key. Therefore, the only possible way to retrieve them would be to use decryption tools they could make available but only after the victim pays a certain fee as ransom. The cybercriminals would also attach two email addresses, namely, support@sysmail.ch and helpsupportmanager@airmail.cc, to facilitate their communication.

Furthermore, they will notify the victim on how much they’re expected to pay in exchange for the decryption services and terms and conditions of payment. For instance, they will claim that if the victim can pay within 72 hours or 3 days, they would be entitled to a 50% discount. In other words, instead of paying the full amount fixed at $980, they would now pay $490, but once the 3 days window closes, only the full ransom fee would be acceptable.

If the victim decides to contact them, they will state that payment can only be made through the purchase of cryptocurrency of the same amount quoted in dollars, which would be transferred to their wallet address. They usually apply this measure in order to prevent the police or any other law enforcement agency from tracing the money to them. As a way of assuring the victim of their expertise, they sometimes request tidbits of the encrypted files so they can offer free sample decryption.

Our cybersecurity experts’ general advice about dealing with cybercriminals is that victims should never pay ransom. The FBI as well as other reputable law enforcement organizations also share same worldview in their guidelines. There are many reasons why ransom payment is seriously campaigned against but the main ones are listed below:

• There is no guarantee you will recover your encrypted files even after paying huge sums of money as ransom;
• When you pay the ransom, you’re encouraging cybercrimes because those behind it would find it profitable;
• More money in the hands of cybercriminals would make it easy for them to expand their criminal activities, thus enabling them to victimize more people;
• Paying a ransom might be illegal in your country.

AVYU ransomware is also notorious for releasing Trojans such as VIDAR or AZORULT that are infamous for stealing sensitive vital details like cryptocurrency wallets, banking details, computer-saved passwords, software account login details, browsing data etc. Once they extract such sensitive information, it gives them more opportunity to commit more scams.

Unfortunately, your computer has already been infiltrated by this variant of STOP/DJVU, you should expedite actions and remove AVYU ransomware virus ASAP. This can be effectively done by booting your computer in Safe Mode with Networking, the ideal setting for ransomware removal. Then you activate any reliable antivirus on the compromised computer.

Remember it is important to use only genuine antivirus if you want to experience optimal result. Therefore, if you’re not sure of any particular antivirus, we recommend INTEGO Antivirus because it proved to be robust and efficient in detecting malware and protecting the PC system in real-time. In addition to that, you can also download RESTORO to help repair damage inflicted on the Windows OS files.

Ransomware Summary

REMOVE MALWARE & REPAIR VIRUS DAMAGE

Ransomware distribution methods & how to avoid them

From a general perspective, the majority of computers become compromised by STOP/DJVU variants such as AVYU ransomware when their users download software contents from online malicious torrents. These viruses often hibernate in pirated copies of software such as “cracks”, fake utility software, illegal key generators, fake game software, etc. Opening any of such can automatically prompt a ransomware attack. Information gathered from different victims reveal that certain software contents are most commonly used by cybercriminals in luring unsuspecting victims. The ones that feature more often than not in the online torrent platforms are listed below:

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

Therefore, if you’re among those that involve themselves in such unwholesome practices, then you should stop such dangerous habit immediately because you’re putting yourself at significant risk of a ransomware attack. There is no gain in trying to cut corners only to end up losing so much money, time, resources, and peace of mind when you eventually become a victim. In addition to that, remember that obtaining copyrighted software content illegally from online torrent platforms is regarded as stealing and is subject to prosecution based on the existing copyright laws.

Instead of having to go through all these, it is much better to obtain such software needs through legitimate and appropriate channels. By so doing, you will be contributing your own quota in helping the industry to grow. Also, have it at the back of your mind that whatever price tag the original content producers put on them, it will always be insignificant compared to the outrageous fees cybercriminals demand as ransom from their victims, and neither would it put your vital data at risk.

Another distribution channel cybercriminals make use of is malicious email attachments. In this method, cybercriminals would compose genuine-looking but fake emails and attach some documents using formats such as DOCX, PDF, and XLS. They make use of these particular ones most times because they are perfect enablers for macro functions or JavaScript, which are suitable for downloading payloads from external sources and uploading them on random computers.

The problem is that trying to sieve out genuine emails from fake malware-carrying ones has increasingly become more difficult in recent times. The reason is that cybercriminals now make their own emails appear exactly like random emails from popular companies/brands such as eBay, DHL, Amazon, and UPS, among others. To make them more compelling, they would attach files with names like Invoice, Order Summary or Tracking Details etc. Sometimes, they even decide to completely obfuscate the actual originating email address, by using email spoofing techniques. Whatever be the situation, we advise everyone to be cautious when opening emails, especially when such email is not expected or out of place.

Lastly, that you’ve become a victim of STOP/DJVU ransomware doesn’t mean you should lose your guards and start experimenting with suspicious websites making dubious claims about having decryption solutions because such hardly exist. Only Emsisoft and DiskTuna currently offer repair tools that have proven to be effective against some variants of this particular ransomware. More reasons why victims should be wary is because some cybercriminals equally spread other types of ransomware disguised as fake STOP/DJVU. Trying to make use of such fake tools can automatically lead to double-file encryption.

More details pertaining to the virus

If you’re curious to know the extent to which your computer was compromised following a ransomware attack, this subsection explains the technical details. The first step the malware takes is to launch build.exe or build2.exe executables followed by winupdate.exe (the update prompt that brings up a fake Windows screen). The next thing it does is to connect with https[:]//api.2ip.ua/geo.json before sending the response to a geo.json file. The malware then proceeds to information gathering stage by storing certain geolocation data such as the computer’s geolocation, time zone, zip code, latitude, and longitude. The screenshot below shows an example of geo.json file.

The virus then creates another file that would contain hardware details, software list available and processes them in information.txt.

The malware would move to the next stage by comparing the country code where the computer is located against a list of encryption-exempted nations they generated. The exempted countries are Russian Federation, Armenia, Tajikistan, Uzbekistan, Ukraine, Kazachstan, Syria, Kyrgyzstan, and Belarus.

If the computer was found to be in any of the aforementioned countries, it will instantly withdraw from any further action. If it passes the geolocation test, the ransomware would then extract the online encryption key from its central server and would merge it with the victim’s ID before saving them on the bowsakkdestx.txt file and to the PersonalID.txt file. Examples of these files are shown in the screenshot below.

Failure to extract an online encryption key (such happens sometimes), it will go for its offline version as a second choice. The difference between the two keys is that the online version is unique to each victim while the offline version is identical to victims on whose computer the virus failed to generate an online encryption key. An indicator of offline ID is the presence of t1 characters appearing at the end of the personal ID and it means there is improved chance of decrypting .avyu files someday. More information about this is provided below.

Full data encryption commences as it scans all the folders while encrypting files with Salsa20. Using RSA-2048, it then locks the encryption key. While this is still going on, the files will be marked with additional extension.

Displayed in the screenshot below is the _readme.txt ransom note the virus drops in all the folders.

The next thing it does is to make use of Command Prompt (vssadmin.exe Delete Shadows /All /Quiet) in deleting all Volume Shadow Copies.

The virus then blacklists certain domains (by modifying Windows HOSTS file) and when the victim tries to access them, an error message DNS_PROBE_FINISHED_NXDOMAIN may pop up.

Remove AVYU Ransomware Virus and Decrypt Your Files

It is very important to urgently remove AVYU ransomware virus with help of genuine AV software. It is advised to boot the computer into Safe Mode with Networking first. It starts the system with limited services and functions, therefore it can stop active malicious processes from hindering with the malware removal procedure. If you do not have an antivirus software yet, consider using our top choice – INTEGO Antivirus.

Once you’ve completed AVYU virus removal, please follow the steps below:

• Inform the appropriate authorities within your country;
• Make use of data back up (if you had one) to restore lost data;
• Learn how to decrypt/repair files affected by STOP/DJVU variants;
• Change all passwords used in the compromised computer as quickly as possible.
• Download RESTORO if you wish to scan and repair virus damage on Windows OS files.

Always ensure you’re using genuine antivirus as well as any other software content at all times and also develop a habit of creating data backups regularly.

OUR GEEKS RECOMMEND

Our team recommends a two-step rescue plan to remove ransomware and other remaining malware from your computer, plus repair caused virus damage to the system:

STEP 1. REMOVE AUTOMATICALLY WITH ROBUST ANTIVIRUS

REMOVE & PROTECT WITH INTEGO

Get INTEGO ANTIVIRUS for Windows to remove ransomware, Trojans, adware and other spyware and malware variants and protect your PC and network drives 24/7.. This VB100-certified security software uses state-of-art technology to provide protection against ransomware, Zero-Day attacks and advanced threats, Intego Web Shield blocks dangerous websites, phishing attacks, malicious downloads and installation of potentially unwanted programs.

Use INTEGO Antivirus to remove detected threats from your computer.

Read full review here.

STEP 2. 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.

GeeksAdvice.com editors select recommended products based on their effectiveness. We may earn a commission from affiliate links, at no additional cost to you. Learn more.

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.