Ransomware

Chaos is a popular ransomware family that spreads a number of malware versions. Upon its infection, most files stored on a system get readjusted becoming no longer accessible. This is done by cybercriminals to extort the so-called ransom from victims in exchange for unblocking data. At the moment, there are 4 most popular versions propagated by Chaos - Axiom, Teddy, Encrypted, and AstraLocker Ransomware. All 4 assign their own extension whilst blocking access to data. For instance, a file like 1.pdf may change to 1.pdf.axiom, 1.pdf.teddy, 1.pdf.encrypted, or 1.pdf.astralocker depending on which version attacked your network. Initially, Chaos used to be called Ryuk .Net Ransomware, but then upgraded and started getting proliferated by the new name. What is more, Ryuk.Net only mimicked encryption with AES+RSA algorithms, but actually used Base64 coding to damage the structure of files. Not excluded the same can be faced in newer versions as well. It is also possible to see a version of Chaos appending a string of random characters to encrypted files - like 1.pdf.us00, 1.pdf.wf1d, and so forth. As soon as encryption (or fake encryption) gets to a close, the virus creates a text note with instructions on how to recover your data. Here are the names as well as the content of each text note created by different versions (README.txt, read_it.txt, READ_ME_NOW.txt.

Tohnichi stands for a ransomware program that changes extensions of files making them all encrypted. .tohnichi is the name of the new extension assigned to each compromised piece. This means all encrypted files will appear like this 1.pdf.tohnichi at the end of the process. The last piece of the puzzle brought by Tohnichi is How to decrypt files.txt, the text file created by malware to explain decryption instructions. First of all, it is stated your network has been hacked, which allowed extortionists to encrypt your data. Then, cybercriminals say they are the only figures able to perform secure and complete decryption of data. For this, victims are asked to establish communication using the Tor browser link and pay for decryption software. The price is kept secret and depends on how fast you contact developers. After completing the payment, developers promise to send a unique decryption tool to regain the data. In addition to that, ransomware developers say they can decrypt several files (that do not contain valuable information) prior to paying the ransom for free. This is a good offer indeed, but still insufficient to trust cyber criminals on an individual basis.

Zeppelin was discovered by GrujaRS, which is a malicious piece that infects computers and encrypts user's data. Programs of such are typically designed to make money on desperate users who got their files locked. As usual, with the encryption, comes a significant change in the file's extension - it renames them using the hexadecimal numeral system to something like this 1.mp4.126-A9A-0E9. In fact, the extension may vary by symbols since the virus can generate random values. Once the encryption is completed, Zepellin creates a text file called !!! ALL YOUR FILES ARE ENCRYPTED !!!.TXT on your desktop. In this note, extortionists offend you with ransom abuse calling you to contact them and buy a specific key. Unfortunately, there is no proven method that could decrypt your data for free at this point. The only way to do so is by following their instructions which is a huge risk. Although the decision lies on your shoulders, we recommend you to delete Zeppelin Ransomware in the guide below.

MOSN is categorized as a ransomware infection that demands money from victims after encrypting data. Normally, such infections strike all potentially important files like photos, videos, documents, databases, and more that comprise some value to victims. The encryption can be spotted by new extensions that are assigned to each compromised piece. For instance, a file named 1.pdf will change to 1.pdf.MOSN at the end of encryption. The same will be seen with other data according to this pattern. Then, soon after this, MOSN installs new wallpapers stretched out across the entire screen that displays a short ransom summary. It states victims should contact developers via walter1964@mail2tor.com e-mail address and pay 300$ in Bitcoin for data redemption. Additionally, MOSN Ransomware creates a text file called INFORMATION_READ_ME.txt that explains the same but also mentions the number of encrypted files and unique ID that should be attached whilst contacting extortionists.

Divinity, Matafaka, and Army are three ransomware infections released by the development group known as Xorist. After your system becomes successfully infected, a virus forces most of the stored files to change their names. Depending on which version attacked your PC, any image, video, music, or document file like 1.pdf will change to 1.pdf.divinity, 1.pdf.matafaka, or 1.pdf.army. After each file ends up visually changed, the above-mentioned versions display a text message in pop-up windows or notepad files (HOW TO DECRYPT FILES.txt). The text differs for each version. To illustrate, Matafaka and Army show barely any information about data decryption. They mention your PC is hacked, but provide zero information or payment instructions to restore the data. The reason for that may be that these versions are still in development and testing. Not excluded that there are complete versions with full-fledged instructions already circulating around the web. Divinity is the only version out of the list having contact details to pay for the ransom. For this, users are asked to write a direct message to @lulzed Telegram or @dissimilate on Twitter. Note that the Xorist Ransomware family uses XOR and TEA algorithms to encrypt personal data. Data encrypted by such ciphers are less likely to be decryptable without the involvement of cybercriminals. Despite this, it is expressly advised against meeting the demands of fraudulent figures.

Herrco is categorized as a malicious ransomware program. Malware of such type searches for important data stored on a PC and blocks access to it using cryptographic algorithms. The main target of Herrco developers centers around business owners that earn supposedly enough money to pay for the decryption of files. Extortionists behind Herrco Ransomware set up their software to change all relevant data with the .herrco extension. For instance, a file named 1.pdf will change its look to 1.pdf.herrco at the end of encryption. Such a change is therefore followed by the creation of How to decrypt files.txt. This is a text file meant to explain decryption in detail. It is said the only way to recover your data on the infected network is to contact developers and pay the so-called ransom. The price is kept secret and depends on how fast you reach out to cybercriminals. To get the conversation with cybercriminals underway, victims are asked to open the Tor link and fill in their personal ID, which is stated on top of the ransom note. Before doing so, it is also proposed to send a couple of files that do not contain valuable information for free decryption.

Keversen is a ransomware-type virus that targets strong encryption of data. This is meant to tug victims into paying the so-called ransom in order to decrypt the blocked files. All instructions on the recovery process get revealed after your files end up encrypted. The Keversen virus renames a wide range of personal data (photos, videos, documents, databases, etc.) with the .keversen extension. To illustrate, a file like 1.pdf will change to 1.pdf.keversen straight after encryption. All of this happens in a blink of an eye, so there is no way to prevent it unless you have a special anti-ransomware program installed. Then, right after this stage of infection gets to a close, Keversen Ransomware moves next to creating the !=READMY=!.txt note, which sheds some words on how to regain your data.

Infa is an example of ransomware infection, which ciphers different kinds of personal data stored on a system. After this process ends up officially over, victims will no longer be able to access their data. Infa Ransomware assigns one common extension (.infa) to all compromised files. This means a file like 1.pdf will be changed to 1.pdf.infa or similarly depending on the original name. Straight after all files have been renamed, the virus forces a text note called readnow.txt to drop on your desktop. This contains general information on how to recover your data. As stated down the note, files like photos, videos, documents, and other formats have been encrypted. To erase the appended ciphers, victims are desired to contact cyber criminals (via stevegabriel2000@gmail.com) and buy a special decryption key. The price equals 0.0022 BTC, which is about 95$ the time we are writing this article. It is also mentioned there are 2 days allocated for file decryption. Unless you complete the payment in time, your files will be wiped out of the system. Choosing to pay decryption is up to your own decision.