Decrypt .loptr files – Locky ransomware virus variant

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.

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.

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

When faced with ransomware like Loptr, 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 Loptr 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.

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 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 .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.

Ransomware Prevention Tips

To avoid Loptr 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 Loptr removal tool