Jaff ransomware / virus (Quick Decryption Solution) - Jul 2021 update

What is Jaff ransomware virus?

Jaff ransomware virus is a threat that can be decrypted and affected files recovered

Jaff ransomware is a crypto-malware that is distributed via Necurs botnet.^[1] The virus targets at least 423 file types and encrypts them with sophisticated ciphers. During this process, the virus adds either .jaff, .wlu, or .sVn file extension after the original file extension. The virus then saves the ReadMe.bmp file and sets it as desktop wallpaper, and drops a ransom note. To determine which version of the ransomware infected your PC, look at the provided list of file extensions and ransom note names used by the virus.

Obfuscated malicious payload arrives as an email that includes a PDF attachment. Once people open this file, it loads an embedded MS Word document (.docm) that asks to enable macros in order to see the content. If a person follows the instruction, malware is dropped and activated on the system. On the affected device, the ransomware starts data encryption procedure and aims at 423 different types of files. It uses a combination of RSA and AES encryption algorithms and appends a particular extension to each of the targeted files.

Following data encryption, it drops ransom notes filled with information about the ransomware attack. The image file (BMP) is set as the affected computer’s wallpaper that informs about Jaff Decryptor System. The other two files include a ransom-demanding message where victims are asked to transfer 2 Bitcoins for data recovery. However, purchasing decryptors from cybercriminals may end up with money loss as well.

After a ransomware attack, you should focus on virus removal. While malware resides on the system, your computer, as well as your privacy, is at risk. Therefore you must remove the ransomware with the help of reputable malware removal programs such as SpyHunter 5Combo Cleaner, Malwarebytes. Only then you should look up data recovery solutions.

IMPORTANT. Victims infected with three initial Jaff versions – .wlu, .jaff, and .sVn file extension viruses can now decrypt files for FREE, thanks to Kaspersky Team. To decrypt files, download the decryption tool using the link provided down in data recovery instructions and let it restore all your files for free.

The virus is executed on the system as soon as a person opens the malicious email attachment.

Jaff ransomware resembles Locky and Dridex viruses because it uses the same Necurs malspam^[2] as the main distribution strategy. However, the structure of the malware indicates that it is not related to these cyber infections, although the payment page is almost identical to Locky's. Cybercriminals just adapted few features of successful ransomware projects.

As we already mentioned, the infected email has an attached PDF file that opens a DOCM file. Once victims click the “Enable Content” button, they activate the malicious script placed in that file and it downloads various files that are necessary to execute and run this malware.

When a file-encrypting virus is executed, it connects to its Command & Control server and informs about a newly attacked device. The C2 server responds with the word “Created” and malware starts the data encryption procedure. It only stays away from system files and other important data that is necessary for running the computer.

Jaff virus is also designed to delete Shadow Volume Copies of the targeted files by executing vssadmin.exe delete shadows /all /Quiet command in order to make data recovery nearly impossible without a particular decryption key. The malware drops ransom notes to each folder that has affected files, where criminals explain how to obtain a decryption key.

Ransom-demanding message also includes a unique victim’s ID and provides a link to the payment website, which can be accessed only using the TOR browser. It includes information on how to buy Bitcoins and how to transfer them to the provided address in order to obtain the decryption key. Once Jaff ransomware has been spotted, it asked to pay 1.82 BTS; however, the newest versions demand to transfer 2 BTC.^[3]

Unfortunately, there are no guarantees that cybercriminals will give you access to the Decryptor. They are interested in getting your money only. Thus, you should not risk losing $3000 and having business with shady people. However, if you have backups, you can call yourself lucky because it’s the only way to restore your files at the moment. Otherwise, chances to get back your files are low, but this situation should not motivate you to pay the ransom.

Instead of risking losing few thousand dollars, you should focus on cyber threat removal procedures. When your computer is virus-free, you can try alternative recovery methods and restore at least some of your files or wait until the official decryptor is released.

An image of the new Jaff ransom note

Detailed analysis of Jaff ransomware distribution methods


Jaff virus uses Necurs botnet to spread malicious spam emails with infected PDF documents. As we already mentioned, this technique has been used in the distribution of Locky. The phishing email has a subject line that has one of these words that are followed by the random numbers, for instance, Copy_0504747, PDF_57583, Scan_15467085, Your Invoice # 87871, or File_2227958. Such letters contain a PDF attachment named “nm.pdf” and might provide numerous reasons why users have to open it.

For instance, one spam campaign simply asks to print two copies of the file.^[4] If a user is tricked into opening it, the PDF file asks to open an embedded DOCM file. Depending on what version of PDF reader is installed on the attacked device, the file might open a DOCM file automatically, or it might ask a user to open it.

Once the Word file is opened, it delivers a message that this document is protected and the user needs to click “Enable Content” button. The button hides a malicious macro command which is designed to contact a malicious domain to download ransomware-related files to execute the Decryption System.

Thus, if you do not expect to receive any document or file, you should not open any suspicious email attachments. Before opening the attached files, you need to make sure that you know the sender and can trust him or her.^[5] Otherwise, delete such email immediately.

The explained technique was used to push .jaff and .wlu ransomware variants. However, since June 13, 2017, the ransomware developers slightly altered the distribution technique and started pushing the malspam containing the .sVn file extension virus. This time the malicious actors use such and similar subject lines for the malicious messages: Invoice PIS1314074, Invoice PIS8938690.

The emails contain a ZIP file entitled invoicepis8938690.zip, invoicepis9587975.zip, or similarly. This ZIP attachment contains another ZIP attachment called HF4YIDIIL.zip, B9UHRNO5.zip, or similarly. Extracting the second folder places a Windows Script File on the system called identically as the previous ZIP folder – B9UHRNO5.wsf, HF4YIDIIL.wsf, and similarly. Launching the .wsf file activates a script that connects to a malicious domain and downloads the malicious payload.

Jaff ransomware might also be distributed via social networks and file-sharing sites. Thus, you might receive a link from a friend (or unfamiliar person) that suggests watching a video or picture. Before clicking on such links, you should always make sure that it’s safe to open. For instance, you can ask your friend whether he or she sent it or not.

What is more, malware might also be promoted as a useful program on various P2P networks. If you need to install a particular program, you should avoid using unknown download sites. Always choose official developers’ or publishers’ websites in order to prevent the installation of malicious programs.

Update May 2017: New design and .wlu file extensions used

The second wave of the virus has hit the web, and this time the malware seems to have undergone some adjustments. First of all, the latest virus version looks completely different from the original. The criminals have labeled this new virus “Jaff Decryptor” instead of the original “ decryptor system” and made changes to the overall design of the ransom note and ransom payment site.

The malware now looks much more professional than it appeared in the beginning. Besides, the changes were not carried out only on the visual level. The virus has undergone modifications in its source code as well: the new .WLU extension has been added to the list of unusual file endings that this virus appends to indicate encrypted files.

What hasn’t changed, though, is the method of ransomware distribution. It still spreads around through malicious spam campaigns and tries to trick users into downloading it on their computers as a supposed invoice file. The subjects of these files will feature titles such as Copy of Invoice 99483713 or Invoice(58-0710). Please note that the numbers may change which each individual attack. So, be careful and don’t download any files received from unfamiliar senders or generally untrusted sources.

Update June 2017: New variant uses .sVn extension

“New month, new extension” seems to be the motto of the Jaff ransomware developers. The researchers have found a new variant of ransomware that appends encrypted files with .sVn extensions. The discovery has been made by Derek Knight, a security researcher who has been investigating spoofed spam emails supposedly received from copy machines in the companies of its potential victims.

These emails arrive under subject names such Message from KM_C224e. Inside them comes an attached file called SKM_C224e54955163156.zip which carries a malicious executable. When activated the executable would download the virus on the computer and start encrypting files, marking the already affected documents with .sVn extensions. New extensions in ransomware typically indicate a new virus version.

In this case, this is justified by the renamed ransom note and image which replaces the desktop background after the ransomware infection. Now, these files are called !!!!README_FOR_SAVE FILES.txt and !!!SAVE YOUR FILES.bmp. Unfortunately, this virus version is not decryptable either. However, the recovery methods below are always there for you to try out.

Update June 15, 2017: Jaff ransomware decryptor is available

The infamous ransomware that seemed to be undefeatable at first appeared to be not as sophisticated as it seemed at first. Of course, it did take a lot of time and patience for Kaspersky experts to analyze the samples of the ransomware and go step-by-step to create an all-in-one decryptor for Jaff file virus family.

The new tool was released on June 14, 2017, and it is capable of restoring .wlu, .jaff, .sVn file extension files back to their original condition. Remember that before using this tool, you must get rid of the ransomware and all of its components. Use a powerful malware remover to eliminate the ransomware before using the decryptor.

Remove Jaff ransomware completely before running the decryption tool

The only safe way to remove the infection from the device is to run a full system scan with a reputable malware removal program. We want to discourage you from trying to delete ransomware manually because it might have injected legitimate system processes and modified Windows Registry.

Thus, you can easily cause more damage by unintentionally stopping important processes or deleting crucial entries. Do not hesitate and install Malwarebytes, SpyHunter 5Combo Cleaner, or other malware removal programs.

If you cannot do that, restart your computer to the Safe Mode with networking as shown in the instructions below. Then you should be able to install a security program and perform automatic Jaff virus removal. Once the computer is virus-free, you can restore your files from backups or try alternative recovery solutions.

Kaspersky Labs have updated their RakhniDecryptor, a tool capable of decrypting various types of ransomware. Download RakhniDecryptor and make sure you have the 1.21.2.1. version (or higher).

• Click Start scan and select a particular folder to find files locked by the ransomware.
• The decryptor will ask you to select a ransom note. Once you select it, hit the Open button and then wait until the decryptor decrypts files. Be patient – this might take a while.
• Repeat with all folders that contain important encrypted files.