STOP/Djvu ransomware is one of the most widespread ransomware families. First activity of that virus type was detected in 2018, and still its activity is very high. Being targeted mainly on simple users, this ransomware can be a perfect example of a “classic” ransomware.
Let’s check out the specific features of this family. Each family has its own special elements, which allow the virus analysts to distinguish the ransomware into different families.
|File Extenstions||".yqal", ".moia", ".rigj", ".robm", ".pqgs", ".iisa", ".futm", ".utjg", ".qmak", ".qdla", and etc.|
|Ransom||From $490 to $980 (in Bitcoins)|
|Distribution||Third-party downloaders, installers, peer-to-peer networks, RDP exploits, etc.,|
The majority of STOP/Djvu ransomware injections were contributed through the compromised software. Third-party downloaders, keygens, tools that allow to avoid license checking - all these things are exploited heavily. Since a big number of extraneous downloaders and keygens are detected by antivirus programs, users don’t worry about the advice to disable their security tool, or to add the downloaded program to the whitelist. All such programs are often spread through peer-to-peer networks, so you must check each app precisely before running it. The best solution is to scan the downloaded file(s) with anti-malware software.
Another way that is used to public computers is Remote Desktop Protocol (RDP) vulnerabilities. Those security breaches allow the third party to intercept the packets you send to the remote desktop and ones remote desktop sends to you. There is no problem for virus creators to infiltrate the malicious packets into ones you are attempting to receive from a remote desktop. Fortunately, experienced users or system administrators know how to set up the RDP in an appropriate manner, to avoid security breaches.
Exploit kits. It is quite hard to describe all exploits used in STOP/Djvu ransomware distribution. The total number of used ones is massive, and their variety is so big that I can easily compose a separate article. But at all exploit kits are utilities that allow you to use the programs’ vulnerabilities to perform the action you want. Malware injection is just a single action of dozens of possible ones. The only problem is to force the user to get in the situation when the exploit can be used. Such a situation may appear in the web browser, or while making use of programs. You can barely predict the exploiting moment while using the app, but will definitely catch that something is wrong if someone will try to infect you through the web browser. Dubious pages are too hard to disguise, so, being attentive, you will likely understand that something is wrong.
The STOP/Djvu family uses the AES-256 encryption algorithm. That is not the strongest method, but it still provides an overwhelming amount of possible decryption keys. To brute force the 78-digit number of keys, you need 3.5 unvigintillion years (1*10^65), even if you use the most powerful regular PC. Quantum computers can show a bit better results, but it is still too slow to get your files back while you are alive.
The exact algorithm of encryption is next: malware scans each folder for the files it is able to encrypt. Then, when it finds the target, it makes a copy of your file, removes the original one, encrypts the copy and leaves it instead of the removed original. Such a procedure is done to prevent the situation when you have already opened the file, so ransomware is not able to read it because of the Windows restrictions. To each encrypted copy, the virus adds the specific extension - ".yqal" and ".moia". Then, ransomware creates a _readme.txt file in the folder where the encrypted file is located, and goes to the next folder.
Such an encryption method can be exploited for file recovery. Since the original file is deleted, you may try to recover it using the file recovery tools. The less time is passed - the bigger the chance to get your files back, so hurry up!
Another specific moment that can help you to use the files even after the encryption is the fact that STOP/Djvu ransomware encrypts only the first 150KB of each file. Hence, you can try to run a big file, such as video or music, without the encryption. Similar feature also works with other ransomware families - Dharma, Conti and Makop encrypt the same 150KB.
Ransom note: _readme.txt
Ransom note is the same for the whole ransomware family. In fact, it is one of the main signs of to which family the certain ransomware belongs. Here is the typical note for STOP/Djvu family:
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@example.com Reserve e-mail address to contact us: firstname.lastname@example.org Your personal ID: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
|🔗 Remove Yqal Virus Ransomware (+File Recovery)|
|🔗 Remove Moia Virus Ransomware (+File Recovery)|
|🔗 Remove Rigj Virus Ransomware (+File Recovery)|