The recent release of STOP/DJVU variant ransomware is called Zida. As usual, the name was derived from the .zida file extension that this malware is appending to all encrypted files. Technically, renaming the file with .zida extension somehow affects why users may not be able to open the infected data. Hence, the major cause for this is that Zida ransomware have encrypted it with a complex method. By encrypting, it only means that the virus has scrambled the core data and decryption tool is needed to restore it to original version.
How Zida Ransomware Spreads
The method of distribution for any kind of ransomware including Zida is always the same. Cyber crooks behind this virus are making use of spam mass-mailing campaign in order to reach computer users randomly. They usually attached Zida ransomware executable on the email and masked it as valid document. Persuading the email recipient is simply accomplished by making the messages attractive and states that further details are in the attached file. Once user accessed it, Zida ransomware initiates the attack.
Other ways to propagate Zida ransomware is through software bundles. Attackers are enclosing the virus to certain cracked programs or freeware and upload them to servers like file-sharing networks, torrents, and software download websites. When user runs the setup, Zida ransomware is likewise executed and will begin to infect the computer.
Zida Ransomware Infection
Right after Zida virus infects a computer; it will locate major files like documents, spreadsheets, presentations, images, photos, drawings, archives, databases, and so on. Then, it processes a sophisticated encryption method to deny victims’s access to their own files. Aside from the encryption, it renames the data with .zida file extension. To give an example, the normal reviewer.doc will transform into reviewer.doc.zida after it was fully encrypted.
After the encryption process of entire target files, Zida ransomware will leave a note containing the procedures it takes in locking the files as well as instructions on how victims can decrypt all Zida files. As usual, attackers are requesting ransom payment amounting to $980 that covers the decryption tool and private key. If victims can contact the threat makers within the given 72 hours period, the ransom demand can be lowered to half than original price. Though, malware researchers do not recommend paying the ransom and instead, they advise to just backup all encrypted files and wait for the official free Zida decryption tool.
How to Remove Zida Ransomware
Ransomware files are placed deeply into the system and on various locations, thus, thorough scanning is vital to totally remove Zida virus. Aside from our suggested tool, you may also run your own security program.
Though affected files may be impossible to decrypt due to complexity of the encryption, you can still try recovery method like alternative tool, Shadow Explorer or Previous Version as described below.
Stage 1: Scan the Computer with Anti-Malware Tool
1. Download free anti-malware scanner called MalwareBytes Anti-Malware.
Malwarebytes Anti-Malware Download Link (this will open a new window)
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 Zida 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 2: Double-check for Zida’s leftover with Microsoft’s Malicious Software Removal Tool
1. Download the free scanner called Malicious Software Removal Tool.
Malicious Software Removal Tool Download Link (this will open a new window)
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 Zida 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 Zida 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 Zida ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.
Stage 3 : Unlocking files with Zida Decryption Tool
Emsisoft Decryptor for STOP Djvu will work only if affected files were encrypted using Offline Keys. Zida ransomware uses the alternate Offline Keys during encryption if there is a problem encountered while communicating to a remote command-and-control server. Follow the guide to start recovering .zida encrypted files.
1. As precautionary measures, we suggest to BACKUP all your .zida encrypted files first on a separate media (USB Drive, Flash Drive, DVD Discs, etc…).
2. Download Emsisoft Decryptor for STOP Djvu from this archive page.
3. Right-click on decrypt_STOPDjvu.exe and click “Run as Administrator“. Windows may prompt “Do you want to allow this app…” just click Yes to continue.
4. By default, the tool will pre-populate the locations where encrypted files were identified. To include other directories, simply click Add Folder button.
5. To start recovering files infected by Zida ransomware, click on Decrypt button to start the procedure. The interface will display status of the current decryption process.
We will update this section once the full decryption tool is on hand. In the meantime, please try other options below if the above procedure is not not effective.
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 Zida ransomware infection. To use this tool and recover files affected by the 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 encrypted files on the computer.
Option 2: Use ShadowExplorer to restore files encrypted by Zida 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 Zida 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 Zida 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.