Windows users infected with the Dharma ransomware are in for a serious security predicament, but there may still be a good chance to decrypt .dharma files.
Dharma ransomware has been in the wild for about four months, and its extortion activities have affected thousands of end users along with hundreds of enterprise networks over this time span. The main fingerprintable property of this sample is the .dharma extension being affixed to ransomed data, hence the generic name of the infection. In the meantime, a few concurrent campaigns leveraging the same malicious code also involve the .wallet, .xtbl and .zzzzz strings labeling victims’ encrypted personal files. Taking after its predecessor called CrySiS, the malady in question employs the Advanced Encryption Standard (AES) to achieve the information lockdown effect. Sometimes cybercrooks implement this symmetric cryptographic algorithm incorrectly and researchers are able to create free decrypt tools, but this isn’t the case with the Dharma virus.
The ransomware under scrutiny contaminates computers in a way that’s hard to call top-notch. It arrives with email spam that delivers ZIP files extracting into contagious JS or VBS objects. The subject of such a message will typically look like a lure, for instance, it may pretend to be an energy bill, some sort of accounting information, a job offer or a receipt. The attached entity is tailored to automatically initiate the infection chain once opened. Then, after downloading the entirety of its components onto the target machine, the Dharma ransomware begins scanning all local, network and removable data repositories for numerous types of user data.
Having encrypted these files, the perpetrating program stains each one with the .[email address].dharma extension, where the part in brackets is variable. The original names of files remain intact. As an illustration of this morphing, a sample “CV.docx” document will be renamed to something like “CV.docx.[email@example.com].dharma”. The email attribute may assume the shape of one of the following strings: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, or email@example.com.
The ransomware also creates a number of ransom manuals to provide the victim with a walkthrough on file recovery. These are called README.txt, README.jpg, and Info.hta. The first two contain the following message, “ATTENTION! At the moment, your system is not protected. We can fix it and restore files. To restore the system write to this address: [email address for campaign]”. The Info.hta ransom note, in its turn, looks different and provides somewhat more information. The common denominator for both types of these how-to’s is that the victim is pressured into sending a message to a specified email address in order to receive a response with further instructions. At the end of the day, the recovery boils down to paying 0.5 Bitcoin or more, depending on the extortionist group.
Fortunately, in an unexpected move, someone released the master decryption keys for Dharma in early March. Kaspersky Lab and ESET picked up this invaluable information and updated their free decryptors to handle this ransomware. However, this only applies to cases when the .dharma string is appended to files. Meanwhile, those who are facing the .wallet, .xtbl or .zzzzz variant of the Dharma virus should try a number of forensic tricks that may work for file restoration.
Dharma ransomware automated removal and data recovery
Owing to an up-to-date database of malware signatures and intelligent behavioral detection, the recommended software can quickly locate the infection, eradicate it and remediate all harmful changes. So go ahead and do the following:
1. Download and install the antimalware tool. Open the solution and have it check your PC for PUPs and other types of malicious software by clicking the Start Computer Scan button
2. Rest assured the scan report will list all items that may harm your operating system. Select the detected entries and click Fix Threats to get the troubleshooting completed.
Data recovery toolkit to the rescue
Some strains of ransomware are known to delete the original files after the encryption routine has been completed. As hostile as this activity appears, it can play into your hands. There are applications designed to revive the information that was obliterated because of malfunctioning hardware or due to accidental removal. The tool called Data Recovery Pro by ParetoLogic features this type of capability therefore it can be applied in ransom attack scenarios to at least get the most important files back. So download and install the program, run a scan and let it do its job.
Dharma ransomware manual removal and file recovery
Some ransomware strains terminate themselves after completing the encryption job on a computer, but some don’t. Furthermore, the Dharma virus may prevent victims from using popular antimalware tools in order to stay on board for as long as possible. Under the circumstances, it may be necessary to utilize the Safe Mode with Networking or System Restore functionality.
- Restart the machine. When the system begins loading back up, keep pressing the F8 key with short intervals. The Windows Advanced Options Menu (Advanced Boot Options) screen will appear.
- Use arrow keys to select Safe Mode with Networking and hit Enter. Log on with the user account infected by the ransomware.
- Click on the Search icon next to the Start menu button. Type msconfig in the search field and select the System Configuration option in the results. Go to the Boot tab in the upper part of the GUI.
- Under Boot options, select Safe boot and click the Apply button. A prompt will appear to reboot the computer so that the changes take effect. Select the Restart option and wait for the system to load into Safe Mode. Again, log on with the ransomware-stricken user account.
In Safe Mode, the ransom Trojan won’t keep security software from running or otherwise thwart troubleshooting. Open your preferred web browser, download and install an antimalware tool of choice and start a full system scan. Have all the detected ransomware components removed in a hassle-free way.
- Open Windows Advanced Options Menu as described in the previous section: hit F8 repeatedly when the PC is starting up. Use arrow keys to highlight the Safe Mode with Command Prompt entry. Hit Enter.
- In the Command Prompt window, type cd restore and hit Enter
- Type rstrui.exe in the new command line and press Enter
- When the System Restore screen pops up, click Next, select a restore point that predates the contamination, and use the application’s controls to roll back the system to this earlier state.
Be advised that even after the ransomware is removed, files will still be encrypted and inaccessible. The malicious code cleanup part, however, is important because it keeps a relapse of the infection from occurring further on and eliminates all opportunistic malware.
Ways of non-ransom file recovery
Cracking the crypto used by this ransom Trojan is more of a science fiction thing rather than an attainable prospect for the masses. This is why the troubleshooting in predicaments of this sort is a matter of two approaches: one is to pay the ransom, which isn’t an option for many victims; and the other is to apply instruments that take advantage of the ransomware’s possible weaknesses. If the latter is your pick, the advice below is a must-try.
Checking one’s options regarding this workaround is doable in two ways: through the Properties menu of each file or by means of the remarkable open-source tool called Shadow Explorer. We recommend the software-based way because it’s automated, hence faster and easier. Just install the app and use its intuitive controls to get previous versions of the encrypted objects reinstated.
Alternatively, you can leverage the Previous Versions feature, which is native to Windows operating system. This method is more cumbersome that the use of ShadowExplorer, but it can help restore the most important individual files on condition that the ransomware failed to disable the Volume Snapshot Service on the computer. Right-click on a file of choice and select Properties. Then, go to the Previous Versions tab as illustrated below.
Go ahead and pick the file’s latest backup version on the list. Use the Copy or Restore buttons to reinstate this object to a new path or to its original folder, respectively.
Ransomware Prevention Tips
To avoid Dharma ransomware and other file-encrypting infections in the future, follow several simple recommendations:
- Toggle your email provider’s anti-spam settings to filter out all the potentially harmful incoming messages. Raising the bar beyond the default protection is an important countermeasure for ransom Trojans.
- Define specific file extension restrictions in your email system. Make sure that attachments with the following extensions are blacklisted: .js, .vbs, .docm, .hta, .exe, .cmd, .scr, and .bat. Also, treat ZIP archives in received messages with extreme caution.
- Rename the vssadmin.exe process so that ransomware is unable to obliterate all Shadow Volume Copies of your files in one shot.
- Keep your Firewall active at all times. It can prevent crypto ransomware from communicating with its C&C server. This way, the threat won’t be able to obtain cryptographic keys and lock your files.
- Back up your files regularly, at least the most important ones. This recommendation is self-explanatory. A ransomware attack isn’t an issue as long as you keep unaffected copies of your data in a safe place.
- Use an effective antimalware suite. There are security tools that identify ransomware-specific behavior and block the infection before it can do any harm.
These techniques are certainly not a cure-all, but they will add an extra layer of ransomware protection to your security setup.
Revise your security status
Post-factum assessment of the accuracy component in malware removal scenarios is a great habit that prevents the comeback of harmful code or replication of its unattended fractions. Make sure you are good to go by running an additional safety checkup.
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