Viruses

If you cannot open your files, and they've got .craa extension added at the end of the filenames, it means your PC is infected with Craa Ransomware, the part of STOP/Djvu Ransomware family. This malware is tormenting its victims since 2017 and has already become the most widespread ransomware-type virus in history. It infects thousands of computers per day using various methods of distribution. It is using a complex combination of symmetric or asymmetric encryption algorithms, removes Windows restore points, Windows previous versions of files, shadow copies and basically leaves only 3 possibilities for recovery. The first is to pay the ransom, however, there is absolutely no guarantee, that malefactors will send the decryption key back. The second possibility is very unlikely, but worth trying – using a special decryption tool from Emsisoft, called STOP Djvu Decryptor. It works only under a number of conditions, that we describe in the next paragraph. The third one is using file-recovery programs, which often act as a workaround for ransomware infection problems. Let's observe the ransom note file (_readme.txt), that the virus places on the desktop and in the folders with encrypted files.

Esxi (ESXiArgs) Ransomware is a malicious infection that targets organizations by exploiting vulnerabilities in VMware ESXi - a virtual machine tool used for managing and optimizing various processes within organizations. Security reports indicate that cybercriminals exploit known vulnerabilities in VMware ESXi to gain access to servers and deploy ESXiArgs ransomware onto the targetted system. Once done, the virus will start looking to encrypt files located on the virtual machine with the following extensions: .vmdk, .vmx, .vmxf, .vmsd, .vmsn, .vswp, .vmss, .nvram, .vmem. For each encrypted file, the ransomware will also create a separate file with .ESXiArgs or .args extension with metadata inside (likely necessary for future decryption).

Being a successor of Djvu Ransomware, Coba is a ransomware-type virus that targets personal data. Just like other malware of this type, Coba runs data encryption to demand monetary ransom from victims. All files attacked by Coba (including pictures, databases, documents, etc.) will be restricted from access and altered visually as well. For example, a file like 1.pdf will change its look to 1.pdf.coba at the end of encryption. Developers of this ransomware variant apply the .coba extension to each of the target files stored on a system. The next thing it does after manipulating data extensions creates a ransom note (_readme.txt) that contains decryption instructions. Once users open it up, they will be presented with text written by cybercriminals. This text provides information on how to return the encrypted data.

SkullLocker is a new ransomware variant. The research indicates it was developed on the basis of Chaos Ransomware – another devastating and well-known infection. Upon successful infiltration, SkullLocker encrypts access to files, adds its own .skull extension, and creates a ransom note (read_it.txt) with decryption instructions written in the Polish language. Here is a full text presented in the note along with its translation to English. Overall, cybercriminals demand users make a payment within 72 hours, otherwise, the data will be permanently lost. Users are asked to familiarize themselves with payment and recovery details via the attached TOR link. In addition, the note advises against trying to recover files manually as doing so may cause permanent damage to files.

Coaq Ransomware is the subtype of STOP Ransomware (or DJVU Ransomware) and has all the characteristics of this family of viruses. Malware blocks access to the data on the victim's computers by encrypting it with the AES encryption algorithm. STOP Ransomware is one of the longest living ransomware. First infections were registered in December 2017. Coaq Ransomware with such suffix is yet another generation of it and appends .coaq extensions to encrypted files. Following the encryption, the malware creates a ransom note file: _readme.txt on the desktop and in the folders with encoded files. In this file, hackers provide information about decryption and contact details, such as e-mails: support@freshmail.top and datarestorehelp@airmail.cc.

New instances of STOP Ransomware (DjVu Ransomware) continue to damage users files all over the world. STOP/Djvu Ransomware is a specific type of ransomware that has been active since 2017. It is a type of file-encrypting malware that encrypts victims' files and demands payment in exchange for the decryption key. This crypto-virus uses a complex AES encryption algorithm to block users' access to their data and extort a ransom of $490 or $980. One of the new variations of extension, that appeared in October 2022, is: .cosw. Corresponding ransomware got the name Cosw Ransomware. The virus adds such suffixes to the end of encrypted files. If your files got such an ending and are not accessible, it means your PC is infected with STOP Ransomware. Malware developers slightly modify the virus technically.

Goba Ransomware, which is actually next generation of STOP Ransomware appeared in the beginning of March 2023. This virus encrypts users' essential files, such as documents, photos, databases, music with AES encryption and adds .goba extensions to affected files. This ransomware is almost identical to numerous previous versions of the malware, that we described earlier, and belongs to the same authors, and uses the same e-mail addresses (support@freshmail.top and datarestorehelp@airmail.cc) and the same Bitcoin wallets. Full decryption is almost impossible, however, partially your data can be restored using instructions in this article. After the virus finishes, it creates _readme.txt file with the ransom note on the desktop and in the folders with affected files.

If your files have been suddenly altered with the .wannasmile extension (for example, 1.pdf.wannasmile) and you are now shown a ransom-demanding message in the pop-up window, then you are likely dealing with WannaSmile Ransomware. Although there is not enough justification for this, WannaSmile could be a new version of another identically named ransomware from 2017 (by Iranian developers), which assigned the .WSmile extension. In general, such malware is typically designed to render data inaccessible (by running encryption) and then extort money from victims for its decryption.