STOP Ransomware (DJVU Ransomware) is officially the most common virus-encrypter in the world. The encryptor operates according to the classical scheme: it encrypts files, adds a new extension to them, and places a ransom note on the infected machine. More than 50% of ransomware-infected computers are infected with STOP Ransomware. It has got second name - DJVU Ransomware, after the extension .djvu, that was appended to the files on first infected computers. With several minor and major modifications virus continues its devastating activity in present days. Recent variation of malware (Ogdo Ransomware) adds .ogdo extension to files. Of course, affected files become inaccessible without special "decrypter", that have to be bought from hackers. Here is _readme.txt ransom note, that ransomware places in every folder and on the desktop.
Back in 2016, KeRanger became the very first ransomware that attacked Mac users. Most users were mind-blown when realized that their data is locked because they downloaded a legitimate BitTorrent Client called Transmission. At that time, cybercriminals managed to hack their website and ingrain a file-encrypting virus into a new version that was about to come out. Therefore, users inadvertently caught a malware attack by updating the previously installed application. Unfortunately, laboratories have not identified the appropriate measure to decrypt the inflicted data. Instead, victims offer a paid solution which is buying a decryption program. The transaction has to be made via the Tor browser by paying 1 BTC (around 407 at that time), now Bitcoin accounts for roughly $5,260. Extortionists also claim that they will answer any of your questions if you are really motivated to pay a ransom. You can also decrypt 1 file via the Tor page linked in the note. As mentioned, third-parties tools are currently unable to decipher the locked data.
Whilst most ransomware developers focus on infecting Windows-based systems, AgeLocker targets Mac and Linux, instead. The ransomware positions itself as a business-oriented virus that spreads on corporative companies, however, attacks on regular users happen as well. The encryption process looks pretty similar to Windows, the only difference is using different extensions and file formats. AgeLocker applies its personal command prompt to run the encryption process. Files that have been impacted by AgeLocker get assigned with personalized extensions based on user's names. It is impossible to identify which file was infected because of AgeLocker ciphers the original name and adds a random extension at the end. Some people reported that their files were added with the .sthd2 extension and the name of encrypted files starts with the age-encryption.org URL-address. Once all files get locked successfully, the virus sends a ransom note (security_audit_.eml) to the victim's e-mail.
AESMewLocker Ransomware is a real menace that targets your data by encrypting it with AES File Format algorithms. It is nothing peculiar to the ransomware world. The virus popped up on multiple forums a couple of days ago and raised a big question around its victims - how to decrypt files? For now, there are no viable ways to unlock files that are getting encrypted with the .locked extension after penetration. All of your files become inaccessible and can be unlocked, only if you meet the swindler's requirements and pay for the decryption key. The key itself is not cheap, you have to spend 0.05 BTC and contact extortionists to get decryption instructions. All of this information is stated in a ransom note (READ_IT.txt) created after successful encryption.
IOCP is a ransomware infection that encrypts personal data and keeps it locked until victims pay a so-called ransom. It uses the random 5-letter extension to replace the original file appearance. Once it gets added, your file will reset its icon and change it to
1.mp4.UAKXC, for example. Some people get wrong saying that IOCP is part of Conti Ransomware. This not true because Conti uses AES algorithms whilst IOCP applies Salsa20 and ChaCha20, instead. After your files get blocked, the virus creates a ransom note (R3ADM3.txt) containing instructions on how to decrypt your data. It is said that you should write an e-mail to one of the attached addresses. No time boundaries are set, however, cybercriminals say that unless you pay for the decryption software, your files will be published around the web. For the moment, because this ransomware is relatively new, experts have not found a viable way to decrypt files for free.
Kasp Ransomware (latest version of STOP or DjVu Ransomware) is extremely harmful and one of the most active encryption viruses. More than half of ransomware submissions to ID-Ransomware (ransomware identification service) are made by victims of STOP Ransomware. Although it has been in circulation for a couple of years, the number of infections caused by the Kasp Ransomware continues to increase. It may be somewhat ironic, but most of the victims (at the moment) are users of pirated software. The version of the virus, that is under consideration today, adds .kasp extension to files. The malicious program also creates a text file (called _readme.txt) in each infected folder, which explains to the user that his computer is infected and he will not be able to access his data until he pays a ransom of $980. Tampering with encrypted files can cause permanent damage, and the chances of guessing the correct decryption key are virtually zero. Alternatively, of course, you can pay the ransom. But keep in mind that you are dealing with criminals who can still increase the size of the ransom.