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Decrypt .loptr files – Locky ransomware virus variant

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This post provides analysis of the Locky ransomware edition that appends the .loptr extension to encrypted files and leaves loptr-[4_chars].htm ransom note.

Some strains of ransomware surface and quickly vanish to never come back, but some evolve in order not to become stationary targets. The latter trend mainly applies to lineages of crypto malware architected by crooks with lots of resources on their hands. One of such families, referred to as Locky, has been through multiple iterations since it emerged back in February 2016. The latest variant that’s currently in intense rotation features flawless implementation of RSA and AES cryptographic algorithms. By combining the use of 2048-bit and 128-bit keys, this sample thwarts decryption beyond ransom and thus poses a serious risk for integrity of one’s data. There is barely any ambiguity when it comes to identifying this particular specimen – it concatenates the .loptr extension to every locked file and drops a decryption how-to named loptr-[4_random_characters].htm.

Encrypted .loptr files and ransom notes in the folder
Encrypted .loptr files and ransom notes in the folder

The text of the HTM ransom note has remained invariable across all editions of the Locky family. It says, “!!! IMPORTANT INFORMATION !!!! All your files are encrypted with RSA-2048 and AES-128 ciphers. … Decrypting of your files is only possible with the private key and decrypt program, which is on our secret server.” Then go detailed instructions that boil down to installing Tor browser, visiting a personal .onion domain assigned to each victim, and buying the decrypt tool on the payment portal named Locky Decryptor Page. The size of the ransom is in the range of 0.15-1 Bitcoin, which is close to the average amount in today’s extortion ecosystem.

loptr-[4_random_characters].htm ransom note by Loptr ransomware
loptr-[4_random_characters].htm ransom note by Loptr ransomware

While some competing ransomware programs are distributed via multiple channels, Locky has been consistently sticking to a single vector throughout its existence timeline. Powered by the botnet called Necurs, it reaches computers through malspam. The payloads are deposited on computers through contagious ZIP email attachments that unsuspecting recipients open and thus let the virus in. Although there is hardly any diversification of attack vectors in place, the reach of the Loptr virus is quite broad due to professionally tailored spam messages and streamlined payload execution. This particular variant, though, has a flaw that prevents it to contaminate machines running old Windows editions, including XP and Vista.

Having trespassed on a machine, Loptr ransomware deploys some reconnaissance by identifying which files are most likely valuable to the victim. It scans local drives, network drives and removable media for extensions that correlate with popular data formats. Every matching entity is subject to illicit encryption, which may take quite some time depending on the amount of such information spotted. The .loptr string that the virus subjoins to enciphered files isn’t the only external change – it scrambles filenames and replaces them with 36 random hexadecimal characters. Accessing these items is no go, because there’s crypto in the file tweaking mix. So victims are faced with a dilemma: to pay the hefty ransom, or try something alternative first. Unfortunately, the robust encryption of ransomware has yet to be defeated. So the only applicable way to restore .loptr files without meeting the attackers’ demands is to utilize specially crafted data recovery software or take advantage of Shadow Copies unless the infection had deleted them.

Loptr 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

Download .loptr files virus remover

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.

Download Data Recovery Pro

Data Recovery Pro

Loptr 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 .loptr file 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 Loptr ransomware using Safe Mode with Networking

Remove Loptr ransomware using Safe Mode with Networking

Boot into Safe Mode with Networking. The method to do it depends on the version of the infected operating system. Follow the instructions below for your OS build.

  • 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.Boot into Safe Mode with Networking on Windows Vista and 7
  • 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.Boot options on Windows 8, 8.1 and 10
  • 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.

Get rid of Loptr ransomware using System Restore

Get rid of Loptr 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 .loptr extension 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.

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 .loptr file variant of Locky 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 Loptr 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.

Download Loptr ransomware removal tool

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