The Lper virus, known as a ransomware, is part of the STOP/DJVU family. This malware family is notorious for file encryption and extortion. When the Lper virus infects a computer system, it scans the system for files like videos, photos, documents, and more. It alters the file structure and appends the “.lper” extension to each encrypted file, making them inaccessible and unusable without the decryption key.
Lper Virus Overview
Lper
🤔 Lper virus can be classified as ransomware that originates from the DJVU/STOP ransomware family. Its main target is to cipher files that are important to you. After that ransomware virus asks its victims for a ransom fee – ($490 – $980) in Bitcoin.
The Lper virus is a malware type that encrypts your files and coerces you into paying for their restoration. This ransomware ciphers various file types. Encrypted files can be identified by a distinct “.lper” extension. The affected files become inaccessible and unusable.
Then, the ransomware demands a ransom payment in Bitcoin from the victims, ranging from $490 to $980. Usually, a ransom text file is named as “_readme.txt“.
Lper Ransomware uses Salsa20 encryption algorithms to scramble the contents of the targeted files. Since Lper virus uses such a robust ciphering method, it becomes incredibly hard, if not impossible, to find the decryption key without the assistance of the attackers.
Once Lper malware finishes the encryption, it shows a ransom note to the victim, asking for a ransom payment for the decryption key. The ransom note contains instructions on how to make the payment and often contains threats of permanent data loss or increased ransom amounts if the demands are not met within a specified timeframe.
I have compiled an all-encompassing list of potential solutions, tips, and practices to stop the Lper virus and recover your files. There are cases where you can recover the files, while sometimes, it may be impossible.
📌 Important Reminder!
It is critical to say that paying off the ransom is not a guarantee of the successful files recovery. The individuals who stand behind the Lper virus are known for their untrustworthiness. There were the cases where people have paid the ransom, only to be denied by the cybercriminals with the decryption key provision.
Lper uses a unique key for every victim, with one exception:
The Lper virus is similar to other DJVU ransomware samples like Cdpo, Cdtt, Cdwe, and Cdaz. This virus encrypts a wide range of common file types and appends its distinct “.lper” extension to all files. For instance, a file named “1.jpg” would be altered to “1.jpg.lper” and “2.png” to “2.png.lper“.
Upon successful encryption, malware creates a special text file named “_readme.txt” and places it in every folder containing the encrypted files. It as well adds this file to the desktop, so the victim will not miss the attack even without opening folders.
The image below provides a visual representation of files with the “lper” extension:
Encrypted Files by STOP/DJVU Ransomware
| Name | Lper Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .lper |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Win32/Injector.CWKU, Ransom:Win32/Egregor.UX!MTB, Trojan:Win64/BumbleBee.EM!MTB |
| Symptoms |
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| Fix Tool |
To remove possible malware infections, scan your PC:
6-day free trial available. |
This message asking payment is for restore files via decryption key:
_readme.txt (STOP/DJVU Ransomware) – The terrifying warning insisting users to pay off the ransom to unlock the encoded data contains these frustrating warnings.
Lper ransomware arrives as a set of actions that are meant to perform certain activities on a victim’s computer. One of the first processes being launched is winupdate.exe, a sneaky process that shows a fake Windows update alert during the attack. That is needed to convince the victim that their PC has become slow because of a Windows update.
Meanwhile, the ransomware runs another process (which name commonly consists of 4 random characters) which commences scanning the disk for target files and ciphering them. Next, the ransomware deletes Volume Shadow Copies from the disk using the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once deleted, it becomes virtually impossible to recover the previous computer state using System Restore Points. The issue is, ransomware operators are eliminating any built-in Windows methods that could aid the victim to restore files for free. In addition, the hackers modify the Windows HOSTS file by adding a list of domains to it and mapping them to the localhost IP. As a result, the victim will witness a DNS_PROBE_FINISHED_NXDOMAIN error when trying to access one of the blacklisted websites.
We’ve observed that ransomware endeavors to restrict websites that post various how-to guides for computer users. It is clear that by hindering specific domains, the crooks are seeking to prevent the victim from accessing relevant and helpful ransomware-attack-related information online. This malware also saves two .txt files on the victim’s computer that provide attack-related information – the victim’s public key and personal ID. These two files are named bowsakkdestx.txt and PersonalID.txt.
After all these modifications, the malware doesn’t cease. Variants of STOP/DJVU have a tendency to install Vidar password-stealing Trojan on compromised systems. This threat has an extensive list of capabilities, including:
- Stealing Steam, Telegram, Skype login / password;
- Stealing cryptocurrency wallets;
- Downloading other malware to the computer and running it;
- Stealing browser cookies, saved passwords, browsing history, and more;
- Viewing and manipulating files on victim’s computer;
- Allowing the hackers to perform other tasks on the victim’s computer remotely.
The cryptography algorithm used by DJVU/STOP virus is AES-256. So, if your data got encrypted with an online decryption key, the chances to get your files back are quite low. Thing is, online key is unique for each victim, and picking it will take too much time.
Obtaining the online key in any other way is also nearly impossible. It is stored on a command server controlled by the crooks who promote the Lper malware. For receiving decryption key the payment should be $980. To see the payment details, the victims should contact the hackers by email ([email protected]).
The message by the ransomware states the following information:
ATTENTION! Don't worry, you can return all your files! All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key. The only method of recovering files is to purchase decrypt tool and unique key for you. This software will decrypt all your encrypted files. What guarantees you have? You can send one of your encrypted file from your PC and we decrypt it for free. But we can decrypt only 1 file for free. File must not contain valuable information. You can get and look video overview decrypt tool: https://we.tl/t-WJa63R98Ku Price of private key and decrypt software is $980. Discount 50% available if you contact us first 72 hours, that's price for you is $490. Please note that you'll never restore your data without payment. Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours. To get this software you need write on our e-mail: [email protected] Reserve e-mail address to contact us: [email protected] Your personal ID: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
How To Remove STOP/Djvu Ransomware?
Video Guide
How To Decrypt .lper Files?
How to restore big files?
Try removing .lper extension on a few big files and opening them. This malware has issues with large files encryption. Either the virus accessed and did not lock the file, or it bugged and did not add the filemarker. If your files are very large (2GB+), such a situation is highly probable. Please, let me know in comments if that will work for you.
The newest extensions released around the end of August 2019 after the criminals made changes. This includes Cdpo, Cdtt, Cdwe etc.
As a outcome of the alterations made by the criminals, STOPDecrypter is no longer backed. It has been replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft.
You can download free decryption tool here: Decryptor for STOP Djvu.
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Select folders for decryption.
Based on the default configurations, the decryptor will automatically choose the available directories in order to decode the currently accessible drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the help of the “Add” button.
Decryptors typically propose several options depending on the specific malware family. The existing possible options are displayed in the Options tab and can be activated or disabled there. You may locate a detailed list of the currently active Options below.
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Click on the “Decrypt” button.
As soon as you add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.
Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:
The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.
The Emsisoft Decryptor might display different messages after a failed attempt to restore your files:
✓ Error: Unable to decrypt file with ID: [your ID]
There is no corresponding decryption key in the Emsisoft decryptor’s database.
✓ No key for New Variant online ID: [your ID]
Notice: this ID appears to be an online ID, decryption is impossible
Your original files were encrypted with an online key. So no one else has the same encryption/decryption key pair. File recovery is only possible through paying the ransom. 🙁
✓ Result: No key for new variant offline ID: [example ID]
This ID appears be an offline ID. Decryption may be possible in the future.
An offline key was used, but files could not be restored (the offline decryption key isn’t available yet). Nonetheless, this message is a good news for you, since it is possible to restore your files in the future. 🙂
It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.
✓ Remote name could not be resolved
This stands for a DNS issue present in your system. Consider resetting your HOSTS file to default.
How to Restore .lper Files?
In some case ransomware is not doom for your files…
The Lper ransomware encryption mechanism is next: it ciphers every file byte-by-byte, then saves a file copy, removing (not overriding!) the original file. Hence, the information of the file location on the physical disk is lost, but the original file is not erased from the physical disk. The cell, or the sector where this file was stored, can still hold this file, but it is not present in the file system and can be rewritten by data that has been loaded to this disk after the removal. Hence, it is possible to retrieve your files using special software.
Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected, or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage.
When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data.
As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I was transferring some files from my backup.
Hopefully, this can help some other people in my situation.
Jamie NewlandRecovering your files with PhotoRec
PhotoRec is an free program, which is originally created for file retrieval from damaged disks, or for file retrieval in case if they are unintentionally deleted. However, with time flow, this program got the ability to restore the files of 400 different formats. Hence, it can be used for data recovery after the Lper attack.
First, you need to download this app. It is 100% free, but the developer states that there is no assurance that the files will be retrieved. PhotoRec is spread together with other program of the same developer – TestDisk. The resulting archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.
To launch PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation is required – this program has all the files it need inside of the archive, hence, you can mount it on your USB drive, and help your friends/parents/anyone who has been attacked by Lper ransomware.
Upon the start, you will witness the screen showing you the full list of your disk drives. However, this data is presumably unhelpful, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.
After choosing the disk, you need to choose the destination folder for the retrieved files. This menu is located at the lower part of the PhotoRec window. The best choice is to export them on USB drive or any other type of removable disk.
Then, you need to specify the file formats. This choice is located at the bottom, too. As it was mentioned, PhotoRec can retrieve the files of about 400 different formats.
Finally, you can initiate files retrieval by pressing the “Search” button. You will observe the screen where the results of the scan and recovery are shown.
Lper files recovery Video Guide.
Frequently Asked Questions
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