This entry provides the low-down on the new ThunderCrypt ransomware, which uses asymmetric cipher to lock files and demands Bitcoins for decryption.
Unfortunately, cryptography isn’t entirely about benign scope of use these days. This domain of applied science was originally meant to secure communication, data transfer and information storage. However, cybercrooks ventured into turning this status quo upside down. They cooked up a type of high-profile malicious code that encrypts users’ files in order to hold them for ransom. Ransomware, which is a term denoting this particular category of computer viruses, became a buzzword since the first samples were discovered in the wild. The infection called ThunderCrypt is one of the latest manifestations of this adverse trend. It is currently stirring up a great deal of fuss in the IT security ecosystem, exhibiting malicious characteristics that are extremely difficult to tackle.
ThunderCrypt leverages the RSA-2048 cryptographic algorithm to make one’s important data inaccessible. This means that a 2048-bit public key is generated for an infected computer and used to scramble the inner structure of files. The filenames themselves stay unaltered, but they cannot be opened or edited. The inaccessibility effect isn’t the only way to find out that the malady is inside. The ransomware displays a warning window that explains what exactly happened and what steps can fix the problem.
Specifically, the ransom note reads, “We have encrypted all your personal files!” It goes on to say, “We did this using hybrid RSA-2048 public key encryption. It basically means there is no way to decrypt your files without the private key. The private key is stored on our server. Indeed, we can recover your files. You just have to pay us before the deadline.” The GUI does indicate the deadline, which is the point in time after which the unencrypt task will become unfeasible.
According to this warning, the victim is bound to redeem the files by paying 0.345 BTC, which is worth about 500 USD at the time of this writing. The ransom note provides the infected user’s unique Bitcoin address to submit this ransom. Once the payment has been made and the transaction has been confirmed, the decryption process will supposedly start automatically. To prove that this whole routine works, the felons can allegedly unencrypt one file for free as long as its size is under 10 MB.
ThunderCrypt is mainly making the rounds via malspam that delivers contagious attachments. It’s a very wrong thing to open every file received this way, because that’s how the overwhelming majority of today’s crypto ransomware samples propagate. If the assault happens to have taken place, make sure you don’t get hustled into paying the ransom right way. First, figure out whether alternative recovery techniques can help.
ThunderCrypt 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.
ThunderCrypt 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 ThunderCrypt 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 recovery of files ransomed by ThunderCrypt
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 ThunderCrypt 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.