Efji ransomware is a complicated type of virus. It can infect the computer system files but at the same time, it was designed to damage common files like documents, spreadsheet, databases, archives, videos, photos, images, drawings, and so on. When we learned that Efji ransomware is part of the STOP/DJVU malware group, it is not surprising to know how much damage it can cause to infected computer because similar distress were brought by previous variants like Lyli, Kolz, Copa, and hundreds more.
Spread tactics of Efji ransomware
Through spam email campaign, hackers were able to spread Efji ransomware to random targets. With years of infecting and hacking the computers globally, these attackers were able to amass huge amount of email addresses. Now, they are exploiting these gathered contact details to deploy Efji ransomware.
This mass-mailing method is usually in disguise as valid business inquiry conversing about payment, deliveries, invoicing, taxation, partnership, salary, or any queries relevant to office works. Efji ransomware is attached as file that contains the complete details and because of this; recipients were often tricked into opening it. If this happens, Efji ransomware will initiate the attack and starts to drop various malicious files on the computer. A Windows registry entry is likewise added by the virus to ensure that it runs the code on every Windows start-up.
Efji ransomware encryption and decryption
As soon as the virus becomes operational, searching the drive for target files will be the first on its errands. Efji ransomware makes sure that the files are rendered inaccessible by encrypting them with complex algorithm, reason why it is impossible to restore. At the same time, the virus appends the data with .efji files extension. As a result, the simple file abcde.doc will turn into abcde.doc.efji after the encryption.
Attackers are offering ways for effective file recovery, though it requires victims to remit steep amount of payment. This ransom demand must be sent to designated Bitcoin wallet as stated in the ransom note generated by Efji ransomware. Here is an excerpt of the _readme.txt document file.
Don’t worry, you can return all your files!
All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files…
|Threat Name||Efji Ransomware, Stop, DJVU|
|Threat Type||Crypto-virus, File Locker, Encryption Virus|
|Ransom Amount||$490 – $980|
|Ransomware Note File||_readme.txt|
|Virus Alias||Ad-Aware : Trojan.GenericKDZ.70420|
AegisLab : Trojan.Win32.Stop.j!c
Avast : Win32:DropperX-gen [Drp] BitDefender : Trojan.GenericKDZ.70420
ClamAV : Win.Trojan.Tofsee-9770082-1
Emsisoft : Trojan.GenericKDZ.70420 (B)
ESET-NOD32 : A Variant Of Win32/Kryptik.HGLF
Ikarus : Trojan.Win32.Crypt
Kaspersky : HEUR:Trojan-Ransom.Win32.Stop.gen
Malwarebytes : Trojan.MalPack.GS
McAfee : Trojan-FSUC!97F1059D7A6D
Microsoft : Ransom:Win32/StopCrypt.AK!MTB
NANO-Antivirus : Trojan.Win32.Stop.hxumvf
Palo Alto Networks : Generic.ml
Panda : Trj/GdSda.A
Sophos AV : Mal/Generic-S
Symantec : ML.Attribute.HighConfidence
TrendMicro : Ransom_StopCrypt.R002C0DJ320
For complete details including full detection list, hash file, file names, and technical behavior (registry actions, shell commands, and processes) of Efji ransomware, please refer to this VirusTotal page.
Backup your files
One important step before proceeding with the procedures below is to backup your files. Ransomware are not the same. Each has its unique sets of payloads aside from encrypting the files with complex method. Others tend to delete the infected files after certain period, while others keep them concealed on hidden places. In addition, ransomware decryption tools are not guaranteed to be perfect, there are instances that files suffer from damages during the decryption process.
So, create a backup copy of your entire Efji encrypted files right now.
Efji Ransomware Removal Guide
First thing to do is remove the Efji virus before attempting the decryption. Remember that as long as the ransomware is active, it will repeatedly encrypt the files on the compromised computer.
Infection of Efji ransom virus is dangerous to the system because it can inject files that runs each time Windows starts. To prevent the malicious files from loading, Windows operating system must run with minimal process and it can be done through SafeMode With Networking.
Stage 1 : Temporarily Disable System Restore on Windows OS
Because Efji and relevant virus is capable of reinstating itself by exploiting the System Restore of Windows, we suggests that you temporary disable System Restore while executing the steps. This option is also helpful to effectively run a full scan on the computer.Do not forget to enable back System Restore after completing the removal of Efji ransomware. This feature is vital in reinstating the operating system to previous normal working condition in case of problems or conflicts occurs.
Stage 2 : Start Windows in Safe Mode With Networking
Windows 10 Guide
1. Click on Windows logo and select Power icon when options pop-ups.
2. Select Restart from the options while pressing Shift key on the keyboard.
3. Choose an Option window will appear, select the Troubleshoot button.
4. On next window, please choose Advanced Option.
5. On Advanced Option window, click on Startup Settings and then, click Restart button to reboot the computer.
6. When Windows boot on Startup Settings, press function key F5 or number 5 on keyboard.
Windows 8 Guide
1. Click Windows Start icon at the lower left section of the screen.
2. Open Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup and then, click on Restart Now button.
4. Once the computer starts in Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings and then, click Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.
Stage 3 : Scan the Computer with Anti-Malware Tool
Ransomware files are placed deeply into the system and on various locations, thus, thorough scanning is vital to totally remove Efji virus. Aside from our suggested tool, you may also run your own security program.
To remove Efji automatically, scanning the computer with this efficient anti-malware tool is suggested. This scanner does not just uncover known threats like viruses or malware, it is also effective in discovering hazardous ransomware like Efji.
1. Download free anti-malware scanner called MalwareBytes Anti-Malware.
2. After downloading, install the program. It may run automatically or you have to double-click on the downloaded file MBSetup.exe.
3. Carry out the installation with default setup process.
4. After the installation process, click the Get Started button to launch the program.
5. Continue with the prompts until the main program opens.
6. On the main console, click on Scan to run most complete detection method to find hidden objects associated to Efji ransomware.
7. Scanning may take a while. Please wait until the anti-malware tool is done with the checking.
8. Once the scan has completed, the tool will display the list of detected threats. Remove all identified malicious items and restart the computer if necessary.
Stage 4 : Double-check with Microsoft's Malicious Software Removal Tool
1. Download the free scanner called Malicious Software Removal Tool.
2. The tool automatically checks the operating system and suggest appropriate download version. Click on Download button to begin. Save the file to a convenient location, preferably on Desktop.
3. After downloading the file, Windows will prompt that download has completed. Click Run to start scanning for Efji ransomware. Another option is to browse the location folder and double click on the file to run.
4. The tool will display Welcome screen, click Next. Please note the message "This tool is not a replacement for an antivirus product." You must understand that this program is made specifically to find and remove malware, viruses, Trojans, and other harmful elements on the computer. It was not designed to protect the computer.
5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Efji ransom virus entities and other harmful files left on the computer will be found and removed. For advanced computer user, you can opt for Customized Scan, if there are other drives or folders you wanted to include in this scan.
6. Full scan may take a while, please wait for Malicious Software Removal Tool to complete the tasks. However, you may cancel the scan anytime by clicking on the Cancel button.
7. After scanning, the tool will reveal all identified threats. There may be other threats that our first scan fails to detect. Please remove/delete all detected items.
8. When removal procedure is complete, you may now close Malicious Software Removal Tool. We hope that Efji ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.
Recover Files from Efji Ransomware Infection
On this section, we will provide ways to decrypt files infected with Efji ransomware. Aside from dedicated decryption software and common tools, other options for file recovery are provided. As much as we can, we will update this area whenever there is new and more suitable decryption tool was made available.
Decrypting Efji infected files with Emsisoft Tools
This service from Emsisoft is helpful in unlocking encrypted files without paying the ransom. It gives three ways to detect the ransomware and provide suitable recovery method:
Upload ransom note – This is usually the .txt or .hta files that was generated by Efji ransomware.
Upload the encrypted file – The actual encrypted file. Choose the one that is less than 8MB in size.
Contact information – Enter the email address or any links provided as it appears in the ransom note of Efji virus.
After submitting any of the appropriate data, Emsisoft will attempt to identify the ransomware and provide keys if there are available.
Option 1: Windows Previous Version Tool
Windows Vista and Windows 7 have a feature called Previous Versions. However, this tool is only usable if restore point was made prior to ransomware infection. To use this tool as "recovery option" for files encypted by Efji virus, please follow these steps:
1. Open My Computer or Windows Explorer.
2. Right-click on the affected files or folders. From the drop-down list, please click on Restore previous versions.
3. New window will open display all backup copy of files and folders you wanted to recover. Choose the appropriate file and click on Open, Copy, or Restore. Restoring selected files overwrites the current locked files on the computer. The tool is not actually recovering files encrypted by Efji. Instead, it restores files from backup copy.
Option 2: Use ShadowExplorer to restore files encrypted by Efji Ransomware
Just like Previous Version tool, ShadowExplorer is taking advantage of shadow copy created by Windows. This tool allows you to retrieve older version of files before it was encrypted by Efji ransomware.
1. Download ShadowExplorer from the official web site.
2. Install the program with the default settings.
3. The program should run automatically after installation. If not, double-click on ShadowExplorer icon.
4. You can see the drop-down list on top of the console. Please select proper drive and the most recent point-in-time shadow copies of files you wish to restore prior to Efji ransomware infection.
5. Right-click on the Drive, Folder, or File you wish to restore and click Export...
6. Lastly, ShadowExplorer will prompt for location where you want to save the copy of recovered files.
How to protect the computer from Efji ransomware?
After the removal of the ransomware, it is important to prevent similar incident from happening again. In order to protect the computer effectively, computer user must know how Efji ransomware was able to infect the computer. To minimize the possible infection, staying away from the common sources of this virus is crucial.
How Efji ransomware can infect your computer?
The method of infecting the computers was found to be similar as other common viruses. Though, ransomware like Efji is seen to have efficient deployment via spam email messages, web injectors, malicious software installers, misleading online advertisements, and through another virus infection.
Once the virus is executed, it immediately infects the system. Then, Efji ransomware communicates to remote server so that unique key can be generated for the specific computer. After acquiring the key, it starts to decrypt target files using a complex method that is almost unbreakable. On the last stage of the attack, Efji ransomware demands for ransom money as payment for the decryption tool. To further understand the attack scheme, we have included an infographic below.
Securing the computer against ransomware attack
Do a Regular File Back-up - Always backup your data on a separate storage devices such as external hard drives, optical discs, or online backup services.
Keep Your Software Updated - Make sure that you have the latest software updates especially on the operating system. Recent updates often contain vital security patches to help protect the computer against all forms of threats.
Install a Security Program - Protect the computer with effective anti-virus application using efficient real-time scanning. Regularly run a complete scan to check the computer for presence of malware.
Protect your files with Controlled Folder Access (Windows 10)
For Windows 10 users, aside from protecting the computer using anti-virus or anti-malware programs, one way to protect against ransomware attack is by using Controlled Folder Access. This feature of Windows Defender Security Center may not prevent the Efji ransomware infection, but it can protect the folder and files in general. Follow the steps to enable Controlled Folder Access in Windows 10.
1. Go to Windows 10 Taskbar and search for Windows Defender Security Center.
2. Open Windows Defender Security Center and click on Virus & Threat Protection icon.
3. On next window, please click on Ransomware Protection.
4. Under Controlled Folder Access section, switch the slider to On. That will enable the feature and protect the folder against Efji or any type of ransomware.
5. Click on Protected Folderslink to include additional folders. Make sure that folders where important files are located should be included in the list.
Certain programs maybe blocked by Controlled Folder Access feature. To fix the issue, simply have the specific program to be white listed.
1. Under Protected Folders, click Allow an app through controlled folder access.
2. Next, click the Add an allowed app and include the target executable file.
This Controlled Folder Access feature is one way to protect files against Efji. Other important things to do in keeping files safe against ransomware is through early prevention like keeping programs updated, install an efficient security program, an do regular file backup on a separate media drive.