Decrypt .osiris files and remove Locky-Osiris ransomware virus

A new version of the Locky ransomware is out, which encrypts files using RSA and AES ciphers, appends them with the .osiris extension and demands 0.5 BTC.

The latest update of the Locky ransomware as of December 5, 2016 has brought about a couple of changes to the way this infection manifests itself. The most conspicuous tweak has to do with the new .osiris extension that the perpetrating program affixes to filenames. The threat actors have apparently switched from using Norse mythology to an Egyptian naming theme. The primary attack vector underwent an alteration as well. The payload for Osiris ransomware is delivered with spam emails that contain a malware-tainted .xls file on board. When a user opens this spreadsheet, it turns out blank. The document displays a prompt instructing the victim to “enable content”, which actually translates to activating Microsoft Excel macros. Then, the infection exploits macros to execute the .osiris file ransomware on the targeted computer.

The next phase of the compromise involves a silent scan of the infected PC’s hard drive, removable drives and network shares for personal files. Once the list thereof has been shaped up, the ransomware encrypts the data with a blend of symmetric AES-128 and asymmetric RSA-2048 cryptosystems. Consequently, the victim’s important files can no longer be opened or edited. The private RSA key, which is the critical prerequisite of decryption, is nowhere to be found on the contaminated computer.

The .osiris extension isn’t the only attribute of the new look and feel of one’s affected files. Another problem is that the infection also scrambles filenames according to a brand-new principle. Ultimately, it renames them into long, weird-looking strings of 36 hexadecimal characters similar to F6A7EEC1–F8BA–409E–582A6BCA–85017FD6852D.osiris. This format, obviously, makes it impossible to figure out which file it was before the scrambling.

As opposed to its .aesir and .ZZZZZ file predecessors, the Osiris ransomware leaves a different ransom note. It’s now called OSIRIS-[4 hexadecimal-char ID].htm, where the ID part varies from victim to victim. An actual example is OSIRIS-5b12.htm. This file opens up in the default web browser and provides some preliminary recommendations on restoring the locked data. In particular, it recommends the victim to visit the Locky Decryptor Page using the Tor Browser. The page then tells the user to submit 0.5 BTC to a specific Bitcoin wallet in order to be able to download the automatic decryptor. Be advised, though, that some people never get their private key and decrypt tool even after they pay the ransom. So stick with the recommendations below instead.

Osiris ransomware automated removal and data recovery

When faced with ransomware like Osiris, one of the best shortcuts in terms of removal is to use Combo Cleaner, a lightweight and incredibly effective application with PC security and optimization features under the hood. It detects and thoroughly deletes threats while giving you insights into the overall health of your computer.

This program’s protection power spans modules that forestall all known types of malware, including ransomware and browser hijackers, and take your online security to the next level by blocking phishing sites and other suspicious web pages. Follow these simple steps to eliminate the infection for good:

1. Download Combo Cleaner installer.

Download Osiris remover

^{Combo Cleaner scans your PC with no strings attached, but you’ll have to buy its fully functional version to remove the threats it detects. The disk optimization tools that find large files and duplicates are free to use.}

2. Open the CCSetup.exe file to get started. Several subsequent screens will allow you to make initial customizations so that the program works exactly as you need from the get-go.

3. The installation will be followed by an update of malware signatures. Once this process is through, click the Start Scan button in the left-hand sidebar.

4. Combo Cleaner will then check system locations that are most often polluted by Windows malware. The first scan can take a while to finish.

5. Combo Cleaner will display a system tray notification as soon as the scan is over. Click the Resolve found threats button to view the results.

6. The scan summary shows the names and types of the detected threats as well as their statuses and locations. Click the Remove all threats button and follow further on-screen prompts to get rid of these items.

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 Stellar Data Recovery features this type of a capability and therefore it can be applied in ransom attack scenarios to at least get the most important files back. So use the app to get an idea of what data can be restored and let it do the recovery job. Here is a step-by-step walkthrough:

1. Download and install Stellar Data Recovery.

Download Stellar Data Recovery

2. Open the application, select the types of recoverable files to look for, and click Next.

3. Choose the areas you want the tool to recover from and click the Scan button.

4. Having scanned the specified locations, the program will display a notification about the total amount of recoverable data. Close the dialog and click the Recover button. This will hopefully help you get some of your valuable files back.

Osiris 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 Osiris 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.

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 .osiris 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 Osiris ransomware and other file-encrypting infections in the future, follow several simple recommendations:

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. Another benefit of using the antimalware tool is that it will keep ransomware threats from intruding on your computer further on.

Download Osiris removal tool