Thor virus: how to decrypt .thor files ramsomware

This guide provides the low-down on the newest Locky variant called Thor ransomware and advises on workarounds to decrypt files with the .thor extension.

Yesterday’s edition of Locky ransomware that appended the .shit suffix to one’s files didn’t last. The unexpected news that hit the headlines literally hours later is that a new heir to the vicious throne has been discovered. The successor concatenates the .thor extension instead and renames files to a balderdash of numbers and characters. It goes without saying that a victim’s valuable files also get encrypted, not just renamed. Ultimately, an infected user will be confronted with a change of a random document to something like SU8DRICBA-EG3N-Y5GZ-00BA-A085959612E7.thor. Of course, there exists no regular software that will be able to open this entry. No one but Locky authors have the private decryption key that can revive the skewed information, but they won’t provide it for free.

According to ransom notes called _WHAT_is.html, _[random number]_WHAT_is.html, and _WHAT_is.bmp, the user needs to visit their personal page to purchase the decryption service. The Thor ransomware reiterates the same recommendations in a new desktop background that replaces the original one automatically. The warning claims that all of the victim’s files are encrypted with RSA-2048 and AES-128, two extremely strong cryptosystems that are virtually uncrackable if implemented correctly. The bad news for all those infected is that Locky developers are tech-savvy enough to perform the encryption part of their breach flawlessly.

The whole interaction chain with the cybercrooks takes place in the following way: first, the user is supposed to open one of the above-mentioned _WHAT_is.html/.bmp help files. Locating them is a no-brainer as the ransomware adds them to the desktop and all folders that contain at least one encrypted item. The ransom manual has several, usually two, hyperlinks in it that resolve to the Locky Decryptor Page. A noteworthy nuance is that this page is only accessible with the anonymity-oriented Tor Browser. The resource in question informs the victim about the size of the ransom, which is typically 0.5 BTC ($327), as well as the Bitcoin address to submit it. After the extortionists verify and approve the transaction, they promise to make the automatic decryptor available. There is no certainty that the threat actors will be true to their word, though.

Because there are no weak links in the actual crypto, the .thor extension virus can have a disastrous effect. Under the circumstances, taking efforts to avoid this ransomware is a strongly recommended route. The infection proliferates over phishing, where users receive fake budget forecasts, receipts or invoices. The ZIP archive attached to one of these tricky messages will extract to a .vbs file that furtively downloads a DLL installer of Thor. That being said, it’s a very bad idea to open email attachments like that. Also, performing regular data backups should become everyone’s habit these days. If this variant of Locky has already done its dirty job, start with a few forensic techniques that may be helpful for restoring .thor files.

Thor 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.

Thor 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 Thor infection 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.

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 .thor files

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.

Ransomware Prevention Tips

To avoid the Thor 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.