IRFK ransomware maliciously encrypts files on a computer, then tries to extort the user
- IRFK ransomware maliciously encrypts files on a computer, then tries to extort the user
- Viruses under the ransomware type use stealthy techniques to infect computers
- Details about the ransomware infection: what really happened?
- Remove IRFK Ransomware Virus and Recover Your Files
- Decrypt IRFK files
- Frequently Asked Questions
IRFK ransomware virus is part of the infamous STOP/DJVU ransomware family. Once it infects the target computer, it encrypts all data on it using Salsa20+RSA-2048 encryption algorithm and appends .irfk extension to each affected file. To illustrate, a file that’s been originally called 1.jpg becomes 1.irfk after being infected. The virus also drops ransom note called _readme.txt in every folder while damaging victim’s data. The note introduces cybercriminals intentions and explains that all data was locked with intention to extort the computer user. In order to recover all data, the victim is asked to pay a ransom to get IRFK decryption tool.
IRFK ransomware was created by a cybercriminal gang that’s been releasing similar viruses since 2019. The aim of this malware is to lock files on the target system using encryption algorithms. While encryption itself isn’t malicious, the offenders put it to bad use to extort the computer users. After encrypting all data on the computer, the virus leaves ransom notes suggesting that the victim needs to pay up in order to recover files. The note specifies that pictures, databases, videos, documents, projects and archives were locked and in order to get further instructions on how to pay the criminals, the victim needs to write to attackers via email@example.com and firstname.lastname@example.org (both are included in the _readme.txt file).
Further instructions in the ransom note suggest that the price of data decryption depends upon specific timeframe. According to the note, the attackers are willing to provide 50% discount for those victims who write to the attackers within 72 hours (3 days) starting from the infection timestamp. This means the decryption tool and key costs $490. If delayed any longer, there will be no discount and the victim needs to pay full price, which is $980.
Futhermore, to convince the victim to pay up, the ransom note suggests sending one small file for test decryption. The victim would receive a decrypted version, but only if the file sent contains no valuable information.
When contacted via email, the cybercriminals will explain that the ransom needs to be paid in cryptocurrency. They will also give instructions how cryptocurrency can be purchased and transferred to their virtual wallet address. The only reason why the crooks accept this form of payment is because it prevents law enforcement agencies from tracking them down.
Information security experts and FBI advise against ransom payments. In many cases, victims end up not recovering their files despite paying the ransom; moreover, STOP/DJVU variants are known to install information-stealing Trojans like VIDAR or AZORULT on infected systems, which means they can use collected data to blackmail you further. Besides, paying simply fuels this illegal business model. According to reports, operators of such malware collect millions in USD annually, and such large sums attracts other people to join in. Think of it this way – the more money criminals collect, the more skilled developers they can employ and they can also expand their distributors’ network further.
The most important thing to do if you’ve fallen victim to a crypto-virus attack is to remove malware from your computer immediately. To remove IRFK ransomware virus, we recommend using a robust antivirus software. If you do not have one yet, consider using INTEGO Antivirus which can detect nearly 100% of all malware and also provide you with real-time protection. Additionally, we suggest downloading RESTORO, a tool that can repair virus damage on Windows OS files affected by malware. Please see the guidelines below this article on how to boot your computer in Safe Mode with Networking so that all threats could be eradicated safely.
|Name||IRFK Ransomware Virus|
|Type||Ransomware; Crypto-malware; Virtual Extortion Virus|
|Encryption type||RSA 2048 + Salsa20|
|Previous versions||BBYY, BBII, BBZZ, BBII, HKGT, EFVC, EIJY (find full list here)|
|Cybercriminal email@example.com, firstname.lastname@example.org|
|Additional malware dropped||Azorult or Vidar Trojan|
|Damage||The ransomware infects computers by stealth as it typically arrives in a form of a malicious torrent download. Once in the computer, it encrypts all personal files stored on it and marks each of them with additional .irfk extension. Furthermore, it leaves _readme.txt ransom note in every scanned folder. The virus then deletes Volume Shadow Copies to block access to System Restore points. Additionally, the virus modifies Windows HOSTS file by adding a list of websites to block on the host, thus restricting victim’s access to various computer help sites. This ransomware often infects computers with information stealers such as AZORULT Trojan or VIDAR.|
|Ransom demand||$490-$980 in Bitcoin|
|Distribution||Victims often download this ransomware along illegal torrent downloads, cracked software, activators, key generators or tools like KMSPico.|
|Known software cracks to contain this malware||Corel Draw, Tenorshare 4ukey, Adobe Photoshop, Cubase, Adobe Illustrator, Internet Download Manager, Tally, League of Legends.|
|Detection names||Trojan:Win32/Krypter.AA!MTB (Microsoft), Gen:Variant.Fragtor.36858 (B) (Emsisoft), UDS:Trojan.Win32.Scarsi.gen (Kaspersky), Gen:Variant.Fragtor.36858 (BitDefender), MachineLearning/Anomalous.95% (Malwarebytes), Packed.Generic.528 (Symantec) see all detection name variations on VirusTotal|
|Removal||Remove ransomware and related malware from your PC using professional software of your choice. We highly recommend using INTEGO Antivirus. To repair virus damage on Windows OS files, consider scanning with RESTORO.|
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Viruses under the ransomware type use stealthy techniques to infect computers
Ransomware-type viruses can infect your computer in a variety of ways. Most common distribution methods rely on torrent files, fake ads, exploit kits, malicious email attachments or simply deceptive websites serving various downloads. When it comes to STOP/DJVU ransomware variants like IRFK virus or others, we can confirm that the main attack vector is illegal torrents for popular software cracks. Many victims who got their files encrypted state that the ransomware came along a torrent for pirated software version. Some examples of programs that users attempted to download and activate without paying the license fee are:
- Accurate 5;
- Adobe Photoshop;
- Adobe Illustrator;
- Opera browser;
- Fifa 20;
- Tenorshare 4ukey;
- Microsoft Office 365;
- VMware Workstation;
- League of Legends;
- Internet Download Manager;
- KMSPico (illegal Windows activation tool).
Please remember that this list is not finite and you can get infected with this malware after downloading any crack or keygen for popular programs and games for Windows PCs. Cybercriminals know which programs are popular and use their names to prey on potential victims by uploading torrents for such software in various online listings. Therefore, if you have bad habits of downloading pirated software versions, you risk falling a victim to a ransomware attack.
Our suggestion is to support legitimate software developers and download computer programs only from verified websites only. Trying to avoid license fees can only do a lot of harm to your data – either files saved on your computer or login credentials. These torrents hardly ever come clean as they tend to carry all sorts of malware – viruses, Trojans, keyloggers, cryptocurrency miners and so on. It is worth noting that software license tends to cost less than hefty ransoms asked by cybercriminals.
It gets harder and harder to identify malicious emails nowadays since attackers try to make them look as convincing as possible. They may insert logos, spoof the sender’s email address or try to spark your curiosity by stating that there’s information that you need to review as soon as possible. We advice you to learn how to identify spoofed sender’s email address and avoid opening emails that you didn’t wait for or if you have even a slight suspicion that something’s wrong with the email.
You can also get infected by visiting dangerous online websites or clicking on malicious ad. Cybercriminals often use malvertising, a technique that is used to inject malicious code into legitimate ad networks to infect many users at once. Clicking on such ads or even worse, downloading files promoted by them can compromise your operating system in seconds. The best way to protect your PC against such attacks is to have a robust antivirus with real-time protection feature on your computer.
STOP/DJVU ransomware victims should also know that without a backup, there are no magic tools that can help to decrypt your files. The only exceptions are described in this article on decrypting/repairing files affected by STOP/DJVU variants. Please note that attempts to desperately search for a non-existent decryption tool can result in double file encryption. There are other ransomware strains that target potential victims with fake decryption tools. If you happen to download and run one on your computer, your files will get encrypted again. One example of virus using this distribution technique is ZORAB.
Details about the ransomware infection: what really happened?
It is understandable that you feel unsettled because it is unclear what really happened and what the IRFK ransomware virus did to your computer. In this section, we will go through technical details and overview the modus operandi of this threat.
After being launched on the target system, the ransomware unwraps its processes that may be named as build.exe, build2.exe, build3.exe and similar. Before actually encrypting one’s files, the virus performs a couple of initial checks, for instance, if the victim’s computer’s geolocation is eligible for data encryption. The virus connects to https[:]//api.2ip.ua/geo.json and as a response, geo.json file is saved to the computer. This file contains information such as computer’s IP address, time zone, country code, zip code, latitude and longitude.
The virus then compares the retrieved country code with its exception list, and stops the attack if one of the following countries is detected: Russian Federation, Belarus, Armenia, Tajikistan, Kazachstan, Kyrgyzstan, Ukraine, Uzbekistan or Syria. The reason why the virus avoids infecting victims from these countries are unknown, although it can be explained that users from these countries hardly ever pay ransoms or that the cybercriminals are based in this region themselves.
If the infected computer is based in other country, the virus also runs commands to gather details about the infected system. It saves hardware and software related details in information.txt file. A screenshot of such file contents is shown down below.
Before starting the file encryption process, the ransomware tries to connect to its Command&Control server and get unique encryption key (also known as online key) for the victim along with Personal ID string. The virus then saves these details to bowsakkdestx.txt and PersonalID.txt files. In case the server is unreachable or there are problems with victim’s Internet connection, the virus uses a hardcoded encryption key instead (also known as the offline key). At this point, it is worth mentioning that there are no hopes to decrypt files affected with online key, whereas offline key encryption leaves some chances to recover your data. You can spot offline encryption type by checking the last two characters in your ID in PersonalID.txt file located in C:/SystemID. If these are t1, it means that offline key was used.
The ransomware then runs a fake Windows update prompt called winupdate.exe which shows a progess bar for the victim. This is done in order to convince the computer user that the system slowdown is caused by ongoing legitimate operating system updates. In the meantime, the ransomware uses Salsa20 encryption to lock files and secures this encryption with RSA-2048 public key. To make affected files distinguishable, the malware appends .irfk extensions to original full filenames and drops _readme.txt notes in each data folder.
Below, you can see a screenshot of _readme.txt file used in the latest STOP/DJVU ransomware attacks.
The next step taken by ransomware operators is ensuring that the victim can no longer use System Restore points to recover some of the files. Therefore, the virus deletes Volume Shadow Copies by entering the following command in Command Prompt:
vssadmin.exe Delete Shadows /All /Quiet
You may also notice that you can no longer reach specific websites online. The reason behind this is that the criminals do not want you to find relevant information or help online, therefore they’ve designed the ransomware to add a list of domain names to Windows HOSTS file and map them to localhost IP. This causes DNS resolution problem and causes DNS_PROBE_FINISHED_NXDOMAIN error to appear in web browsers.
In the end, to cause even more damage, the ransomware drops information stealer on the system, either AZORULT or VIDAR Trojan. These threats can be used to access victim’s computer via command line and run commands to steal login credentials for software or web browser-saved accounts, banking details, Skype chat history, cryptocurrency wallets and more. The criminals might use such information for further blackmail.
Remove IRFK Ransomware Virus and Recover Your Files
The most important task after being with such notorious ransomware is to remove it from your computer system. We recommend using an up-to-date antivirus that can automatically detect all malicious files and safely delete them for you. This must be done after booting the computer in Safe Mode with Networking. If you do not have AV software yet, consider using INTEGO Antivirus to remove IRFK ransomware virus. This AV is approved by our team, has excellent malware detection rate and provides real-time monitoring to block attempts to infect your computer. Additionally, we advise downloading RESTORO to repair damage caused for Windows OS files.
If you have already completed IRFK virus removal, now it is time to restore your files from a backup. If you do not have it, follow these guidelines on how to decrypt/repair files locked by STOP/DJVU variants. Additionally, we suggest reporting cybercrime incident to your local law enforcement agencies and changing passwords for all browser-saved accounts as well as for profiles for software installed on your computer.
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IRFK Ransomware Virus Removal Guidelines
Method 1. Enter Safe Mode with Networking
Step 1. Start Windows in Safe Mode with Networking
Before you try to remove IRFK Ransomware Virus virus, you must start your computer in Safe Mode with Networking. Below, we provide the easiest ways to boot PC in the said mode, but you can find additional ones in this in-depth tutorial on our website – How to Start Windows in Safe Mode. Also, if you prefer a video version of the tutorial, check our guide How to Start Windows in Safe Mode on Youtube.
Instructions for Windows XP/Vista/7 users
- First of all, turn off your PC. Then press the Power button to start it again and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. This launches the Advanced Boot Options menu.
- Use arrow keys on the keyboard to navigate down to Safe Mode with Networking option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Open Windows Start menu, then press down the Power button. On your keyboard, press down and hold the Shift key, and then select Restart option.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Networking. In this case, it is the F5 key.
Step 2. Remove files associated with the virus
Now, you can search for and remove IRFK Ransomware Virus files. It is very hard to identify files and registry keys that belong to the ransomware virus, Besides, malware creators tend to rename and change them repeatedly. Therefore, the easiest way to uninstall such type of a computer virus is to use a reliable security program such as INTEGO Antivirus, which also includes data recovery software. For virus damage repair, consider using RESTORO.
Compatibility: Microsoft Windows
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Method 2. Use System Restore
In order to use System Restore, you must have a system restore point, created either manually or automatically.
Step 1. Boot Windows in Safe Mode with Command Prompt
Instructions for Windows XP/Vista/7 users
- Shut down your PC. Start it again by pressing the Power button and instantly start pressing F8 button on your keyboard repeatedly in 1-second intervals. You will see Advanced Boot Options menu.
- Using arrow keys on the keyboard, navigate down to Safe Mode with Command Prompt option and press Enter.
Instructions for Windows 8/8.1/10/11 users
- Launch Windows Start menu, then click the Power button. On your keyboard, press down and hold the Shift key, and then choose Restart option with the mouse cursor.
- This will take you to Windows Troubleshoot screen. Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Tip: If you can't find Startup Settings, click See more recovery options.
- In Startup Settings, press the right key between F1-F9 to enter Safe Mode with Command Prompt. In this case, press F6 key.
Step 2. Start System Restore process
- Wait until system loads and command prompt shows up.
- Type cd restore and press Enter, then type rstrui.exe and press Enter. Or you can just type %systemroot%system32restorerstrui.exe in command prompt and hit Enter.
- This launches System Restore window. Click Next and then choose a System Restore point created in the past. Choose one that was created before ransomware infection.
- Click Yes to begin the system restoration process.
After restoring the system, we recommend scanning the system with antivirus or anti-malware software. In most cases, there won't be any malware remains, but it never hurts to double-check. In addition, we highly recommend checking ransomware prevention guidelines provided by our experts in order to protect your PC against similar viruses in the future.
Alternative software recommendations
Removing spyware and malware is one step towards cybersecurity. To protect yourself against ever-evolving threats, we strongly recommend purchasing a Premium version of Malwarebytes Anti-Malware, which provides security based on artificial intelligence and machine learning. Includes ransomware protection. See pricing options and protect yourself now.
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Decrypt IRFK files
Fix and open large IRFK files easily:
It is reported that STOP/DJVU ransomware versions encrypt only the beginning 150 KB of each file to ensure that the virus manages to affect all files on the system. In some cases, the malicious program might skip some files at all. That said, we recommend testing this method on several big (>1GB) files first.
- Create a copy of encrypted file to a separate folder using Copy > Paste commands.
- Now, right-click the created copy and choose Rename. Select the IRFK extension and delete it. Press Enter to save changes.
- In the prompt asking whether you want to make the changes as file might become unusable, click OK.
- Try opening the file.
STOP/DJVU decryption tool usage guide
STOP/DJVU ransomware versions are grouped into old and new variants. IRFK Ransomware Virus is considered the new STOP/DJVU variant, just like BBYY, BBII, BBZZ, BBII, HKGT, EFVC, EIJY (find full list here). This means full data decryption is now possible only if you have been affected by offline encryption key. To decrypt your files, you will have to download Emsisoft Decryptor for STOP DJVU, a tool created and maintained by a genius security researcher Michael Gillespie.
Note! Please do not spam the security researcher with questions whether he can recover your files encrypted with online key - it is not possible.
In order to test the tool and see if it can decrypt IRFK files, follow the given tutorial.
- Download the decryption tool from Emsisoft.
- Click the little arrow next to your download and choose Show in Folder.
- Now, right-click the file and choose Run as Administrator. If asked, enter administrator's password.
- In UAC window, click Yes.
- Click Yes to agree to software terms in both windows.
- The tool will automatically include C:// disk as a location to decrypt. The file recovery tool will prepopulate the locations to scan, including connected data storage drives or network drives. Click Add folder if you wish to add additional locations.
In Options tab, you can choose to keep encrypted file copies. We recommend leaving this option selected, especially if you do not know if the decryption tool will work.
- Click Decrypt to start restoring IRFK files. You will see the progress in the Results tab. Here, you can see messages from the tool, such as whether the decryption procedure is successful, or you need to wait for an update.
You might also be informed that online key was used to encrypt your files. In such case, the decryption tool won't work for you, and the only way to recover your files is to use a data backup.
Meanings of decryptor's messages
The IRFK decryption tool might display several different messages after failed attempt to restore your files. You might receive one of the following messages:
Error: Unable to decrypt file with ID: [example ID]
This message typically means that there is no corresponding decryption key in the decryptor's database.
No key for New Variant online ID: [example ID]
Notice: this ID appears to be an online ID, decryption is impossible
This message informs that your files were encrypted with online key, meaning no one else has the same encryption/decryption key pair, therefore data recovery without paying the criminals is impossible.
Result: No key for new variant offline ID: [example ID]
This ID appears to be an offline ID. Decryption may be possible in the future.
If you were informed that an offline key was used, but files could not be restored, it means that the offline decryption key isn't available yet. However, receiving this message is extremely good news, meaning that it might be possible to restore your IRFK extension files in the future. It can take a few months until the decryption key gets found and uploaded to the decryptor. We recommend you to follow updates regarding the decryptable DJVU versions here. We strongly recommend backing up your encrypted data and waiting.
Report Internet crime to legal departments
Victims of IRFK Ransomware Virus should report the Internet crime incident to the official government fraud and scam website according to their country:
- In the United States, go to the On Guard Online website.
- In Australia, go to the SCAMwatch website.
- In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.
- In Ireland, go to the An Garda Síochána website.
- In New Zealand, go to the Consumer Affairs Scams website.
- In the United Kingdom, go to the Action Fraud website.
- In Canada, go to the Canadian Anti-Fraud Centre.
- In India, go to Indian National Cybercrime Reporting Portal.
- In France, go to the Agence nationale de la sécurité des systèmes d’information.
If you can't find an authority corresponding to your location on this list, we recommend using any search engine to look up "[your country name] report cyber crime". This should lead you to the right authority website. We also recommend staying away from third-party crime report services that are often paid. It costs nothing to report Internet crime to official authorities.
Another recommendation is to contact your country's or region’s federal police or communications authority.
Frequently Asked Questions
You can only open IRFK files if you have the decryption key, or if you were affected by offline encryption type.
To figure out whether you were affected by offline encryption, please go to C:/SystemID/PersonalID.txt and see if the string inside of it ends in t1. You can also try using Emsisoft Decryptor for STOP/DJVU.
Please follow the guidances provided by the official IRFK decryption tools and believe what they say. If they say it is impossible to decrypt, it really is so. There is no magic tool or human capable of decrypting your files hiding somewhere. Encryption is a technique created to be nearly impossible to decrypt without a special private key (held by the criminals).
We advise scanning with anti-virus, anti-malware, malware removal tools or software like RESTORO to eliminate virus damage on the system. If you do not trust using a single tool, try running one after another. However, we do not recommend keeping several security programs on a computer at once as they can interfere with each other's work.
Beware of fake IRFK decryption tools circulating around the web. Cyber criminals are uploading them to various shady websites, also might be promoting them via suspicious Youtube videos. These programs can infect your computer even more heavily (Trojans, miners, etc.). We suggest being extremely cautious around the web. If there will be an official STOP/DJVU decryption tool available, it will be widely discussed in public media.
Norbert Webb is the head of Geek’s Advice team. He is the chief editor of the website who controls the quality of content published. The man also loves reading cybersecurity news, testing new software and sharing his insights on them. Norbert says that following his passion for information technology was one of the best decisions he has ever made. “I don’t feel like working while I’m doing something I love.” However, the geek has other interests, such as snowboarding and traveling.