Zimba ransomware is a hazardous computer virus that also falls in the classification of File-Coder or Crypto-Virus. The goal of people behind this malware is to block user’s access to their files, make it inoperable and useless. As such, Zimba virus makers will have all the reason to demand ransom money from the victims as payment for the decryption tool and necessary private key. Due to the complex techniques being applied in locking the files, it may be impossible for ordinary computer user to execute a successful file recovery.
Malware researchers DemonSlay335 and JakubKroustek identify Zimba virus as part of the notorious Dharma ransomware family. Therefore, it is expected that this malware could infect huge amount of computers due to wide spread campaign using several deployment techniques like spam emails, web injectors, malicious file installers, dubious online advertisements, and social engineering attacks.
Of all the mentioned strategies for deploying Zimba ransomware, it has a high infection success rate via spam emails. On this scheme, the virus is attached to an email masquerading as inquiry from a prominent organization. Zimba ransomware is embedded and masking as a valid document file. The email messages use inviting content to lure recipients into opening the attached file that will eventually launch the Zimba ransomware attack.
Zimba Ransomware File Encryption
When executed on the computer in any of the above mentioned schemes, the virus starts the attack by establishing a contact to remote command-and-control server (C&C). After learning that Zimba ransomware has successful penetration, the server commands the virus to start the encryption process using the provided public key. This method of file locking is comparable to military-grade encryption and therefore, users own capability is insufficient to decrypt the files. Along the way, target files are appended with email address plus a .zimba file extension. As a result, file like car.doc will become car.doc.id-1A567E00.[email@example.com].zimba. Another example, table.xls will transform into table.xls.id-1A567E00.[firstname.lastname@example.org].zimba after the full encryption process.
As what goes with entire ransomware attack, people behind Zimba ransomware demands ransom money from victims in order to recover all the .zimba files. Unfortunately, it is costly to acquire the Zimba decryption tool and prices may vary depending on the estimation of the attackers on number of files and nature of the victims. They usually demand steep ransom money for businesses and offices and in fact, attackers even threatens to expose confidential data to the public if no ransom payment was received during the allocated period.
Technical Data of Zimba Ransomware
|Threat Name||Zimba Ransomware, Dharma|
|Threat Type||Crypto-virus, File Locker, Encryption Virus|
|Encryption Method||AES + RSA|
|File Extension||.id-(unique id).[email@example.com].zimba|
|Virus Alias||Avast : Win32:RansomX-gen [Ransom]|
Avira : TR/Dropper.Gen
BitDefender : Trojan.Ransom.Crysis.E
Comodo : TrojWare.Win32.Crysis.D@6sd9xy
DrWeb : Trojan.Encoder.3953
Emsisoft : Trojan.Ransom.Crysis.E (B)
ESET-NOD32 : A Variant Of Win32/Filecoder.Crysis.P
F-Secure : Trojan.TR/Dropper.Gen
Kaspersky : Trojan-Ransom.Win32.Crusis.to
Malwarebytes : Ransom.Crysis
McAfee : Ransom-Dharma!717C8741579F
Microsoft : Ransom:Win32/Wadhrama!hoa
Panda : Trj/GdSda.A
Sophos AV : Troj/Criakl-G
Symantec : Ransom.Crysis
TrendMicro : Ransom.Win32.CRYSIS.SM
For complete details including full detection list, hash file, file names, and technical behavior (registry actions, shell commands, and processes) of Zimba 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 Zimba encrypted files right now.
Zimba Ransomware Removal Guide
First thing to do is remove the Zimba 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 Zimba 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 Zimba 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 Zimba 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.
A simpler alternative for Windows 10 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.
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 Zimba virus. Aside from our suggested tool, you may also run your own security program.
To remove Zimba 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 Zimba.
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 Zimba 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 Zimba 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 Zimba 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 Zimba ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.
Recover Files from Zimba Ransomware Infection
On this section, we will provide ways to decrypt files infected with Zimba 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 Zimba 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 Zimba 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 Zimba 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 Zimba 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 Zimba. Instead, it restores files from backup copy.
Option 2: Use ShadowExplorer to restore files encrypted by Zimba 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 Zimba 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 Zimba 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 Zimba 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 Zimba ransomware was able to infect the computer. To minimize the possible infection, staying away from the common sources of this virus is crucial.
How Zimba ransomware can infect your computer?
The method of infecting the computers was found to be similar as other common viruses. Though, ransomware like Zimba 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, Zimba 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, Zimba 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 Zimba 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 Zimba 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 Zimba. 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.