The aim of this ransomware is to temporarily lock victim’s files and restrict access to them, hoping to force the victim to do whatever it takes to recover the files. The _readme.txt note specifies that all files, such as documents, photos, videos, databases and other format data were encrypted. The attackers explain that all files have been encrypted with the strongest encryption and unique key, so to decrypt .nusm files, the victim needs to purchase the special decryption tools from the cybercriminals. The ransom note suggests that the cybercriminals are the only ones who can restore encrypted files back to their original condition. They even suggest “test decryption” service for the victim. The victim can send one encrypted file to the attackers and expect to receive a decrypted version in return. In addition, the criminals provide the decryption software price conditions: if the victim writes to the provided emails within 72 hours (3 full days) from the initial infection timestamp, the criminals offer the decryption software for $490 in Bitcoin. Otherwise, the price jumps to $980. Bear in mind that cybercriminals cannot be trusted and paying the ransom isn’t recommended by cybercriminals and even FBI. There are more than enough reasons not to pay:

The criminals might not provide the decryption tool, even if you decide to pay up.The tool provided by the criminals might be faulty and might be useless in data decryption;Paying the ransom might be considered illegal in your country;Listening to cybercriminals’ hefty demands and transferring money to them is exactly what makes this illegal industry attractive for other people, convincing them to join in. The fact that ransomware operators collect millions in ransoms each year simply proves they rake up more than enough by extorting computer users;STOP/DJVU variants are known to install variant of AZORULT Trojan on infected systems. Therefore, think twice before you make your decision, because these attackers not only try to extort you, but also install an information and password stealer and do not mention a word about it.

Damage caused by ransomware: what has been done to your computer?

NUSM ransomware begins the attack by bypassing Windows security measures and then starts scanning the entire computer system for target file formats to encrypt. It sure bypasses some folders to ensure that the computer continues to function. The algorithm used to encrypt victim’s files is called RSA Salsa 20, a very secure method and the virus applies it only on the first 150KB of the file. While this can entirely corrupt some file formats, visual files such as images/videos can be repaired in certain conditions. To prevent the victim from recovering data using Windows in-built tools, it deletes Volume Shadow Copies. Additionally, the ransomware modifies Windows HOSTS file by adding a set of domains that publish various computer-related information and might provide ransomware-related help for the victim. This is done to confuse the victim and possibly make one panic, thinking that there are a lot of problems with the compromised computer. As stated previously, NUSM virus also drops AZORULT Trojan on the system. This malware is capable of working as a remote access tool and can be used to view, download or delete files from the target system as well as steal various login credentials from applications like Steam and Telegram, also grab browsing history, saved passwords and cookies from them. Finally, this malware is capable of stealing cryptocurrency wallets from the compromised PC. Needless to say, the list of malicious activities performed by the ransomware and the Trojan is lenghty. Therefore, we recommend you to stop the malicious processes in your computer and remove NUSM ransomware virus without any hesitations and as soon as possible. You can use malware removal software of your choice. We recommend using RESTORO to repair virus damage on Windows OS files afterward.

Ransomware Summary

Tricks used for ransomware distribution

Since NUSM ransomware is part of STOP/DJVU virus family, the technique used for its distribution matches all previous variants (such as IGVM‘s or REJG’s). The operators behind this ransomware pack malicious scripts into various illegal downloads, such as software cracks, keygens, KMSPico and others. Once launched, the malicious script connects to an external domain, downloads the ransomware and executes it on the victim’s computer. Often times, the ransomware even displays a fake Windows update prompt. This is done to convince the victim that the update is to be blamed for a sudden system slowdown, while actually the data encryption process is the culprit. Cybercriminals know that there are many computer users who head to various torrent-sharing websites to get paid software for free. Typically, there are a few kinds of software that interests computer users the most – it’s various games and video or photo editing software. However, attempts to get these paid programs for free almost always lead to silent computer installation. For this reason, we recommend you to avoid shady downloads and only look for desired software on their official developer’s or distributors’ sites. What is even worse is that computer users who look for illegal software activation means tend to ignore security software’s warnings about a potentially malicious file, thinking that these are simply false positive detections. Another popular technique used to spread malware is email spam. This is where the attackers get very creative and come up with various topics when targeting potential victims. The one scheme that’s used most frequently is pretending to be a well-known company representative who is sending an important document, such as invoice, payment information or other file that needs to be overviewed by the victim. Unfortunately, opening such email simply starts the malicious script that’s meant to fire the trigger and drop the malicious payload on victim’s PC. The worst part is that these scam emails can be hard to identify nowadays, because the attackers often use email spoofing techniques that allows sender’s email appear legitimate. In other words, the email sender’s email that appears above the message can be different from the one that was actually used to send the email. All STOP/DJVU ransomware victims should beware of new scam technique circulating around: operators of other ransomware strains, such as ZORAB, are advertising fake STOP/DJVU ransomware decryption tools that actually are ransomware in disguise. In this situation, opening such file will result in double file encryption.

Remove NUSM ransomware virus and decrypt or repair your files

If you’ve fallen victim to the described malware, you should remove NUSM ransomware virus as soon as possible. Luckily, it won’t be hard because we provide a free and easy-to-follow virus removal guide below. We strongly recommend using RESTORO to repair virus damage on your system as well. If you have any questions, do not hesitate and get in touch with our team or leave a question down below in the comments section. Once NUSM virus removal is completed, we recommend doing the following steps:

Report Internet crime incident to an authority responsible of handling such cases in your country. You can find some links down below.Look for data backups and, if you have them, use them to recover your files;Follow the guide to decrypt or repair STOP/DJVU files given down below or in this separate post.

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: 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. 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. 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.

Method 1. Enter Safe Mode with Networking

Before you try to remove NUSM ransomware virus virus, you must start your computer in Safe Mode with Networking. Below, we provide the easiest ways to boot PC in the said mode, but you can find additional ones in this in-depth tutorial on our website – How to Start Windows in Safe Mode. Also, if you prefer a video version of the tutorial, check our guide How to Start Windows in Safe Mode on Youtube. Instructions for Windows XP/Vista/7 users Instructions for Windows 8/8.1/10/11 users Now, you can search for and remove NUSM ransomware virus files. It is very hard to identify files and registry keys that belong to the ransomware virus, Besides, malware creators tend to rename and change them repeatedly. Therefore, the easiest way to uninstall such type of a computer virus is to use a reliable security program such as INTEGO Antivirus. For virus damage repair, consider using RESTORO.

Method 2. Use System Restore

In order to use System Restore, you must have a system restore point, created either manually or automatically. Instructions for Windows XP/Vista/7 users Instructions for Windows 8/8.1/10/11 users After restoring the system, we recommend scanning the system with antivirus or anti-malware software. In most cases, there won’t be any malware remains, but it never hurts to double-check. In addition, we highly recommend checking ransomware prevention guidelines provided by our experts in order to protect your PC against similar viruses in the future.

Alternative software recommendations

Malwarebytes Anti-Malware Removing spyware and malware is one step towards cybersecurity. To protect yourself against ever-evolving threats, we strongly recommend purchasing a Premium version of Malwarebytes Anti-Malware, which provides security based on artificial intelligence and machine learning. Includes ransomware protection. See pricing options and protect yourself now.

System Mechanic Ultimate Defense If you’re looking for an all-in-one system maintenance suite that has 7 core components providing powerful real-time protection, on-demand malware removal, system optimization, data recovery, password manager, online privacy protection and secure driver wiping technology. Therefore, due to its wide-range of capabilities, System Mechanic Ultimate Defense deserves Geek’s Advice approval. Get it now for 50% off. You may also be interested in its full review.

Disclaimer. This site includes affiliate links. We may earn a small commission by recommending certain products, at no additional cost for you. We only choose quality software and services to recommend.

Decrypt NUSM files

Fix and open large NUSM files easily:

It is reported that STOP/DJVU ransomware versions encrypt only the beginning 150 KB of each file to ensure that the virus manages to affect all files on the system. In some cases, the malicious program might skip some files at all. That said, we recommend testing this method on several big (>1GB) files first.

STOP/DJVU decryption tool usage guide

STOP/DJVU ransomware versions are grouped into old and new variants. NUSM ransomware virus is considered the new STOP/DJVU variant, just like BPTO, ISWR, ISZA, BPSM, ZOUU, MBTF, ZNSM (find full list here). This means full data decryption is now possible only if you have been affected by offline encryption key. To decrypt your files, you will have to download Emsisoft Decryptor for STOP DJVU, a tool created and maintained by a genius security researcher Michael Gillespie. Note! Please do not spam the security researcher with questions whether he can recover your files encrypted with online key - it is not possible. In order to test the tool and see if it can decrypt NUSM files, follow the given tutorial.

Meanings of decryptor’s messages

The NUSM decryption tool might display several different messages after failed attempt to restore your files. You might receive one of the following messages: Error: Unable to decrypt file with ID: [example ID] This message typically means that there is no corresponding decryption key in the decryptor’s database. No key for New Variant online ID: [example ID]Notice: this ID appears to be an online ID, decryption is impossible This message informs that your files were encrypted with online key, meaning no one else has the same encryption/decryption key pair, therefore data recovery without paying the criminals is impossible. Result: No key for new variant offline ID: [example ID]This ID appears to be an offline ID. Decryption may be possible in the future. If you were informed that an offline key was used, but files could not be restored, it means that the offline decryption key isn’t available yet. However, receiving this message is extremely good news, meaning that it might be possible to restore your NUSM extension files in the future. It can take a few months until the decryption key gets found and uploaded to the decryptor. We recommend you to follow updates regarding the decryptable DJVU versions here. We strongly recommend backing up your encrypted data and waiting.

Victims of NUSM ransomware virus should report the Internet crime incident to the official government fraud and scam website according to their country:

In the United States, go to the On Guard Online website.In Australia, go to the SCAMwatch website.In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.In Ireland, go to the An Garda Síochána website.In New Zealand, go to the Consumer Affairs Scams website.In the United Kingdom, go to the Action Fraud website.In Canada, go to the Canadian Anti-Fraud Centre.In India, go to Indian National Cybercrime Reporting Portal.In France, go to the Agence nationale de la sécurité des systèmes d’information.

If you can’t find an authority corresponding to your location on this list, we recommend using any search engine to look up “[your country name] report cyber crime”. This should lead you to the right authority website. We also recommend staying away from third-party crime report services that are often paid. It costs nothing to report Internet crime to official authorities. Another recommendation is to contact your country’s or region’s federal police or communications authority.