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RSA-2048/AES-128 virus: “All of your files are encrypted with RSA-2048 and AES-128 ciphers”

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Authors of the Locky ransomware have been using two different cryptographic algorithms to their own advantage, the campaign details being highlighted herein.

Anatomy of the new file-encoding infection called Locky features an advanced take on malicious encryption activity. Its developer chose to blend a public-key cryptographic standard and a completely different symmetric algo in a bid to make the victims’ data recovery plans more of a wishful thinking rather than a realistic prospect. When the malware hits a personal computer or a workstation connected to an enterprise network, the user gets a blackmail message that says, “All of your files are encrypted with RSA-2048 and AES-128 ciphers.” The warning goes on to instruct the victim with the following details of the attack they suffered, “Decrypting of your files is only possible with the private key and decrypt program, which is on our secret server.

Locky virus sells victims their own files for Bitcoins
Locky virus sells victims their own files for Bitcoins

The above-mentioned alert has been observed in two forms: one is an image titled _Locky_recover_instructions.bmp which automatically replaces the user-defined desktop background; and the other is a TXT document with the same name that resides inside every infected data directory. The ransom instructions also contain a number of links pointing to a Tor-backed Locky Decrypter Page, where the user is told to send 0.5 BTC to a specified address. For the target’s ‘convenience’, the website suggests multiple services that can be used to buy Bitcoins. According to the extortionists’ allegations, the infected person will be able to download the decoder after the payment.

The zest of this attack is in the way files are modified. Not only will the user’s spreadsheets, documents and images become encrypted beyond regular restoration, but the names of these files get badly twisted as well. Each one gets the .locky extension at the end, and the preceding string turns into a long, gibberish sequence of random symbols that don’t make sense. This way, the ransomware makes it impossible to discern which items were hit.

The first iteration of the Locky virus circulated via a spam campaign that delivered an unsafe Microsoft Word attachment to a great many potential victims. Masqueraded as an invoice, this document would recommend users to enable macros so that the ransomware process could be remotely executed on machines. The latest edition of the Trojan, however, has come to leverage a hidden JavaScript object. This technique allows the malicious code to evade detection by antiviruses. Moreover, the file is now smaller in size, which makes the contamination process less conspicuous. And yet, the good old spam is still in play.

Those who fell victim to this assault shouldn’t take the whole intimidation effect for granted as there are viable file recovery mechanisms other than the payment that the bad guys ask for.

RSA-2048/AES-128 ransomware automated removal and data recovery

When dealing with the RSA-2048/AES-128 threat, you can get a lot of mileage out of the Malwarebytes automatic security tool that will pinpoint and iron out the infection in minutes. Malwarebytes is one of the big names in the anti-malware industry with an immaculate track record of protecting systems against all prevalent forms of harmful code.

The solution uses artificial intelligence (AI) and machine learning to detect both known and zero-day threats, including potentially unwanted programs (PUPs), ransomware, exploits, and malicious sites. It boasts low system footprint, high scanning speed, and intuitive interface where every module clearly explains what it does. Follow the steps below to come through the malware predicament unscathed:

1. Download and install the latest version of Malwarebytes onto your PC.

As part of this step, you will be prompted to specify where you are installing the program (personal or work computer) and toggle the advanced setup options if you so desire. You can use all the premium features for 14 days free of charge.

Download RSA-2048/AES-128 virus remover

2. Once the application is up and running, go ahead and click on the Scan button in the bottom middle part of the GUI. Click the Scan button

3. Wait until Malwarebytes checks for updates of its proprietary Katana detection engine and scans the memory, startup items, registry, and file system for threats. Malwarebytes scan in progress

4. When the scan is completed, go over the report listing the infections that have been identified. Make sure there are checkmarks next to all the unwanted items and click on the Quarantine button as shown below. Malwarebytes scan results

5. You will be prompted to restart your computer to finish the removal process. Click Yes to do it immediately or close the dialog and restart later on. Restart to complete the removal process

6. As soon as the threats have been moved to Quarantine, they can no longer harm your computer. If you are sure that you won’t need to restore any of those items at a later point, click on the Detection History pane at the bottom left of the Malwarebytes home screen, select the Quarantined items tab, and click Delete. Delete quarantined 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.Stellar Data Recovery main screen
  3. Choose the areas you want the tool to recover from and click the Scan button.Select which PC areas to recover from
  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.Recover files

RSA-2048/AES-128 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 RSA-2048/AES-128 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.

Remove RSA-2048/AES-128 ransomware using Safe Mode with Networking

Remove RSA-2048/AES-128 ransomware using Safe Mode with Networking

Get rid of RSA-2048/AES-128 ransomware using System Restore

Get rid of RSA-2048/AES-128 ransomware using System Restore

System Restore enables Windows users to roll back all changes made to the OS since the latest restore point creation time. This feature can help eliminate the most persistent ransomware. Before going this route, though, make sure System Restore had been enabled prior to the breach, otherwise the method will be inefficient.

  • 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.Safe Mode with Command Prompt
  • In the Command Prompt window, type cd restore and hit Entercd restore command
  • Type rstrui.exe in the new command line and press EnterType rstrui.exe command
  • 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.System Restore window

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 encrypted with RSA-2048 and AES-128 cipher

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.

Backups can make your day

Backups can make your day

Not only are you a lucky person in case you’ve been backing up your most important files, but you’re also a wise and prudent user. This isn’t necessarily a resource-heavy activity these days – in fact, some providers of online services are allocating a sufficient size of cloud storage space for free so that every customer can easily upload their critical data without paying a penny. Having removed the RSA-2048/AES-128 ransomware, therefore, all you have to do is download your stuff from the remote server or transfer it all from an external piece of hardware if that’s the case.

Restore previous versions of encrypted files

Restore previous versions of encrypted files

A positive upshot of using this technique depends on whether or not the ransomware has erased the Volume Shadow Copies of the files on your PC. This is a Windows feature that automatically makes and keeps the backups of data elements on the hard drive as long as System Restore is enabled. The cryptoware in question is programmed to switch off the Volume Shadow Copy Service (VSS), but it has reportedly failed to in some cases.

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.

Shadow Explorer

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.

Previous Versions

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 RSA-2048/AES-128 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. Another benefit of using the antimalware tool is that it will keep ransomware threats from intruding on your computer further on.

Download RSA-2048/AES-128 ransomware removal tool

4 Comments

  1. ali

    April 20, 2016 at 7:23 am

    plissssss : key

    Reply

  2. Mahi

    July 22, 2016 at 2:45 am

    I have been infected by rsa 2048
    Unfortunately i dont have back up
    Any ideas ?

    Reply

    • admin

      September 3, 2016 at 11:24 am

      Mahi,

      Peruse and try the steps above based on Shadow Volume Copies of your files and the use of data recovery software. Hopefully it helps.

      Reply

  3. Jim

    July 28, 2016 at 3:50 am

    Thanks for the help, VERY helpful to restore from .zepto attack.
    Jim

    Reply

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