Merl virus is a new malware belonging to STOP (Djvu) ransomware family. It encrypts the victim’s files, changes the names of the affected files, adding .merl file extension to their name, creates a file called “_readme.txt” with a ransom demand message. After the files are encrypted, their contents become inaccessible. The authors of Merl virus demand to pay the ransom in exchange for the key and the decryptor necessary for decrypting the files. Fortunately, there is a free Merl decryptor and several other alternative methods that can help victims of the virus decrypt .merl files and restore the encrypted files to their original state.
Ransomware is one of the most dangerous types of computer viruses. What is characteristic of these viruses is that they stealthily encrypt files of the victim without giving themselves away. Most often, the victim does not notice the activity of a virus that encrypts files. Only when all the files are encrypted, it becomes clear that the computer was the victim of a ransomware attack. If you encounter such a situation, your computer was infected with a virus, and the files on it were encrypted with the .merl file extension, know that we created this article for you and other people faced with the same problem. This article contains a guide with important information about Merl virus, how it functions, how to remove the ransomware from a computer. But more importantly, this article contains detailed instructions with information on how to decrypt .merl files, as well as what other methods exist to restore encrypted files without paying a ransom to criminals.
What is Merl virus
Merl virus is a ransomware that was created to encrypt files located on the victim’s computer, and then extort money to decrypt them. Merl virus sneaks into the system without any visible symptoms, which is why users notice that their computer is infected too late, when the files are already encrypted.
Typically, ransomware like Merl can infect a computer when installing programs downloaded from torrent web-sites as well as when running cracked games, freeware, key generators and other similar software. Upon execution, the virus creates a directory in the Windows system directory, copies itself to this directory, changes some OS settings, and also collects information about the infected computer. After that, Merl virus tries to connect to its command server. If this succeeds, the virus sends data on the infected computer to the server, and from it receives a key (so-called ‘online key’) necessary for file encryption. If the connection to the command server has not been established, then the virus uses a fixed key (so-called ‘offline key’).
The main difference between the online and offline keys is that the online key is in the hands of criminals and cannot be determined. Offline key is fixed and can be determined by security researchers. This gives hope that victims of Merl virus will be able to decrypt files without paying ransom.
What is Merl file
A file with extension ‘.merl’ is a file that has been encrypted by Merl virus and therefore the contents of this file are locked. Each file that has been affected by the virus is renamed in such a way that the ‘.merl’ extension is added to its old name on the right. This means the following, if the file was named ‘document.docx’, then after it is encrypted, it will be called ‘document.docx.merl’. Each file on the victim’s computer becomes the target of Merl virus. No matter where the file is located, on the internal drive or network storage, this file will be encrypted. The virus only does not encrypt files in the OS system directories, files with the extension .dll, .lnk, .bat, ini, .sys and files named ‘_readme.txt’. Thus, the following types of files can be encrypted:
.3fr, .mcmeta, .x3f, .mddata, .ibank, .csv, .xxx, .fos, .xld, .xlsb, .cer, .sidn, .orf, .3ds, .wpl, .1st, .vcf, .der, .menu, .crw, .wdb, .cdr, .qic, .zabw, .ybk, .map, .wpw, .odp, .syncdb, .zdb, .lrf, .vdf, .ztmp, .raf, .ltx, .wps, .ws, .wp5, .wri, .wmv, .iwd, .webdoc, .dbf, .p7b, .mdb, .itm, .wbz, .bar, .rb, .gdb, .xll, .wn, .bay, .bkf, .bc6, .mrwref, .xf, .mef, .xyp, .db0, .pem, .vpk, .lvl, .pst, .webp, .xlgc, .xls, .desc, .1, .srw, .xlsx, .pfx, .docm, .wmo, .das, .big, .rim, .snx, .itdb, .sav, .srf, .wma, .sb, .eps, .xmmap, .x3d, .xy3, .wb2, .rwl, .zif, .asset, .yal, .w3x, .3dm, .png, .css, .fsh, .dazip, .m3u, .wdp, .layout, .mov, .epk, .m4a, .py, .dng, .xbdoc, .sum, .odc, .d3dbsp, .erf, .re4, .xx, .bik, .xdl, .svg, .doc, .wot, .pak, .rofl, .xlsm, .sql, .hplg, .xyw, .crt, .cr2, .x3f, .mlx, .bsa, .t13, .ntl, .wgz, .wcf, .xdb, .xlsm, .pdd, .qdf, .ptx, .mp4, .wps, .wbmp, .xpm, .dcr, .odt, .upk, .wsd, .p12, .jpe, .xmind, .avi, .wbm, .x, .wire, .icxs, .7z, .gho, .zw, .jpg, .mdf, .pptx, .dxg, .slm, .pkpass, .cfr, .2bp, .xar, .wp4, .ncf, .dmp, .psk, .tax, .xlk, .kf, .pptm, .zip, .wpd, .sid, .hkdb, .wpa, .wpt, .iwi, .wp6, .wm, .dba, .jpeg, .kdc, .wpb, .vtf, .wpe, .ai, .wav, .mpqge, .accdb, .0
As we said, Merl file is an encrypted file. To decrypt it, you must use the key and the decryptor. This is reported by the authors of Merl virus, in a message that they leave on the infected computer. This message is in a file called ‘_readme.txt’. The criminals place such a file in every directory where there is at least one encrypted file. An example of the contents of this file is given below.
The contents of this file are a ransom demand message. Criminals report that all files on the computer are encrypted, and only the key and decryptor can decrypt these files and restore access to their contents. Attackers demand a ransom of $980 in exchange for a key and a decryptor. If the victim is ready to pay the ransom quickly, within 72 hours, the size of the ransom is halved to $490. The authors of the virus offer to decrypt one Merl file for free and thus prove the possibility that the files can be decrypted.
|Type||Crypto virus, Ransomware, Filecoder, Crypto malware, File locker|
|Encrypted files extension||.merl|
|Detection Names||Ransom.Win32STOP, UDSDangerousObject.MultiGeneric, TrojanWin32: Kryptik, FileRep.Malware, TRCryptAgent, MalwareWin32.Ransom, TrojanRansomWin32.Stop, TrojanEncoder, Trojan.RansomCrypted|
|Symptoms||Files won’t open. Files are encrypted with a .merl file extension. Your file directories contain a ‘ransom note’ file that is usually a _readme.txt file. You have received instructions for paying the ransom.|
|Distribution ways||Adware. Malicious spam (also known as ‘malspam’). Drive-by downloads (ransomware virus is able to infect the PC simply by visiting a web-page that is running malicious code). Social media, such as web-based instant messaging programs. Remote desktop protocol (RDP) hacking. Torrents.|
|Removal||Merl virus removal guide|
|Decryption||Free Merl Decryptor|
How to remove Merl virus, Recover, Decrypt .merl files
Security researchers confirm that files with .merl extension are encrypted and to decrypt them you need to use a key and special software – decryptor. Fortunately, Emsisoft created a free decryptor. This program allows everyone to decrypt .merl files completely free. Unfortunately, this decryptor is limited in that it can only decrypt files encrypted with an offline key, files encrypted with an online key cannot yet be decrypted. The reason for this is that only the creators of Merl virus have the online key and this key cannot be determined or cracked. In addition to using the decryptor from Emsisoft, there are several other ways to restore the content of encrypted files.
The instructions below detail how to remove Merl virus, decrypt .merl files, and also how to recover encrypted files if the free decryptor could not decrypt them. Read the entire manual carefully. To make it easier for you to follow the instructions, we recommend that you print it or open it on your smartphone.
To remove Merl virus & Recover, Decrypt .merl files, use the following steps:
Remove Merl virus
Of course, if you become a victim of ransomware, the first thing you need to do is perform a full scan of your computer, find and remove Merl virus. If there is no antivirus on your computer, then you need to install it; if there is an antivirus, update it and then perform a full scan. In addition to antivirus, we strongly recommend that you use free malware removal tools. The utilities below will help you find all the components of the ransomware, and then remove it. Do not use only one utility, at least two, since they use different engines, this will significantly increase the chances that Merl will be completely removed.
Remove Merl ransomware with Zemana Anti Malware
Zemana Anti Malware is a tool to remove various types of malware for free. It can find and delete ransomware, trojans, worms, adware, browser hijackers and other malicious software that most ‘classic’ antivirus software fail to pick up on. Zemana is well suited for any user, as it has a simple interface, small size and quick scan.
Please go to the following link to download the latest version of Zemana AntiMalware (ZAM) for Windows. Save it to your Desktop so that you can access the file easily.
Author: Zemana Ltd
Category: Security tools
Update: July 16, 2019
When the downloading process is complete, close all applications and windows on your personal computer. Open a directory in which you saved it. Double-click on the icon that’s named Zemana.AntiMalware.Setup as shown in the following example.
When the installation begins, you will see the “Setup wizard” which will allow you set up Zemana on your PC system.
Once setup is finished, you will see window as displayed on the screen below.
Now press the “Scan” button . Zemana Free program will scan through the whole PC for Merl ransomware and other security threats. A system scan can take anywhere from 5 to 30 minutes, depending on your PC. While the utility is checking, you can see number of objects and files has already scanned.
When the scan get completed, you can check all threats detected on your PC. Make sure all threats have ‘checkmark’ and click “Next” button.
The Zemana will remove Merl crypto virus, other malware, worms and trojans.
Remove Merl with MalwareBytes Free
You can delete Merl virus with a help of MalwareBytes Anti Malware. We suggest this malware removal tool because it can easily remove ransomware, adware software, trojans, worms, spyware and other malicious software with all their components such as files, folders and registry entries.
Installing the MalwareBytes Free is simple. First you will need to download MalwareBytes Anti-Malware on your computer by clicking on the link below.
Category: Security tools
Update: April 15, 2020
After the downloading process is finished, close all programs and windows on your personal computer. Double-click the install file called mb3-setup. If the “User Account Control” dialog box pops up as displayed below, click the “Yes” button.
It will open the “Setup wizard” which will help you install MalwareBytes on your system. Follow the prompts and do not make any changes to default settings.
Once installation is complete successfully, click Finish button. MalwareBytes AntiMalware will automatically start and you can see its main screen as displayed on the image below.
Now click the “Scan Now” button . MalwareBytes AntiMalware program will scan through the whole PC for Merl crypto malware and other security threats. This task can take quite a while, so please be patient. While the MalwareBytes AntiMalware tool is scanning, you may see number of objects it has identified as being affected by malicious software.
Once the checking is complete, MalwareBytes Free will display a list of found items. Once you have selected what you want to delete from your personal computer click “Quarantine Selected” button. The MalwareBytes will remove Merl ransomware virus related folders,files and registry keys and add threats to the Quarantine. Once the process is done, you may be prompted to restart the computer.
We suggest you look at the following video, which completely explains the procedure of using the MalwareBytes to delete adware, hijacker and other malware.
Remove Merl virus with Kaspersky virus removal tool
Kaspersky virus removal tool (KVRT) is a free portable application that scans your PC system for ransomwares like Merl virus, trojans, spyware, worms, malware and allows remove them easily. Moreover, it will also help you remove any other security threats.
Download Kaspersky virus removal tool (KVRT) on your computer by clicking on the following link.
Author: Kaspersky® lab
Category: Security tools
Update: March 5, 2018
Once downloading is finished, double-click on the Kaspersky virus removal tool icon. Once initialization process is finished, you’ll see the KVRT screen like below.
Click Change Parameters and set a check near all your drives. Click OK to close the Parameters window. Next click Start scan button to begin checking your PC system for Merl ransomware and other known infections. A scan may take anywhere from 10 to 30 minutes, depending on the number of files on your personal computer and the speed of your PC system. When a malicious software, adware software or potentially unwanted applications are found, the number of the security threats will change accordingly. Wait until the the scanning is complete.
After that process is complete, Kaspersky virus removal tool will show a screen that contains a list of malware that has been detected as shown in the figure below.
In order to remove all items, simply press on Continue to begin a cleaning process.
How to decrypt .merl files
All files with .merl extension are encrypted and the only way to access their contents is to decrypt them. To decrypt .merl files, you need to use a unique key and decryptor. As we said above, Emsisoft company was able to create a decryptor and found a way in some cases to determine the key that was used to encrypt the files. This allows victims of the virus to decrypt .merl files for free.
To decrypt .merl files, use free STOP (merl) decryptor
- Download STOP (merl) decryptor from the following link.
STOP Djvu decryptor
- Scroll down to ‘New Djvu ransomware’ section.
- Click the download link and save the decrypt_STOPDjvu.exe file to your desktop.
- Run decrypt_STOPDjvu.exe, read the license terms and instructions.
- On the ‘Decryptor’ tab, using the ‘Add a folder’ button, add the directory or disk where the encrypted files are located.
- Click the ‘Decrypt’ button.
This decryptor can decrypt files that were encrypted with an offline key, as Emsisoft found a way to find this key. Unfortunately, files encrypted with an online key cannot yet be decrypted. The online key is unique to each infected computer, and at the moment there is no way to find this key. Of course, criminals have this key, but we do not think that paying a ransom is a way to decrypt .merl files. In the case when the files are encrypted with an online key, there is a chance to restore the encrypted files using alternative methods, which are described below.
How to find out which key was used to encrypt files
Below we show two ways to help you determine what type of key was used to encrypt the files. This is very important, since the type of key determines whether it is possible to decrypt .merl files for free. We recommend using the second method, as it is more accurate.
First of all, you can look at the personal ID that is given in the ‘_readme.txt’ file (ransom note).
Another way, look on disk ‘C’ for ‘SystemID\PersonalID.txt’ file. This is a file in which Merl virus stores the Personal IDs used for encryption.
The ‘Personal ID’ is not a key, it is a set of characters by which everyone can find out which key was used to encrypt files. If the ID ends with ‘t1’, then the files are encrypted with an offline key. If the ID does not end with ‘t1’, then Merl virus used an online key. If you could not understand which key was used to encrypt the files, then we can help you. Just write a request in the comments below.
What to do if STOP (merl) decryptor says “Error: Unable to decrypt file with ID”
If during decryption of .merl files the decryptor reports ‘Error: Unable to decrypt file with ID’, skips files without decrypting them, then two cases are possible why this happens:
- files are encrypted with an ‘online key’, in this case, you need to use alternative methods to restore the contents of encrypted files;
- files are encrypted with an ‘offline key’, but the key itself has not yet been found by security researchers, in this case, you need to be patient and wait a while, in addition, you can also use alternative ways for recovering encrypted data;
How to restore .merl files
If your files were encrypted with .merl extension, then there is a chance that you can recover the files without decryption. We recommend using PhotoRec and ShadowExplorer that are designed to find and recover lost and deleted data. Mostly such programs are paid, but these tools can restore your files for free. Each of these tools has helped many times to recover files after ransomware infection in what would seem to be the most hopeless cases. We want to remind you that before you try to recover files, you need to check your computer for malware, find and remove Merl ransomware.
Use ShadowExplorer to restore .merl files
Modern versions of the Windows OS have one very useful feature. The Windows automatically makes copies of the files you use. These copies are called ‘Shadow Volume Copies’ and are not directly visible to the user. ShadowExplorer will allow you to get easy access to these files, and thus restore the original state of encrypted files. Of course, not everything is so simple, unfortunately very often ransomware deletes these copies, thus preventing the simple recovery of encrypted files. But in some cases, copies of the files remain and allow for quick file recovery. Therefore, our opinion, you need to try this method.
Download ShadowExplorer from the following link.
Category: Security tools
Update: September 15, 2019
When the downloading process is finished, extract the downloaded file to a directory on your machine. This will create the necessary files as shown in the following example.
Start the ShadowExplorerPortable program. Now choose the date (2) that you wish to recover from and the drive (1) you wish to restore files (folders) from as shown below.
On right panel navigate to the file (folder) you wish to recover. Right-click to the file or folder and click the Export button as shown in the figure below.
And finally, specify a directory (your Desktop) to save the shadow copy of encrypted file and press ‘OK’ button.
Restore .merl files with PhotoRec
There is another very good way to recover .merl files – use a tool that finds and restores deleted files. We recommend using PhotoRec. This is one of the few programs that allows you to do this for free. The reason that allows you to recover encrypted files using this method is simple – when you or any program, including the ransomware, deletes the file, this file is not deleted, the Windows OS marks it as deleted and hides it. PhotoRec finds such deleted files and restores them. Thus, at the output, you get files in an unencrypted state. The only thing I want to draw your attention to is that the less you used your computer after ransomware infection, the higher your chance of recovering encrypted files.
Download PhotoRec from the following link. Save it on your Desktop.
Category: Security tools
Update: March 1, 2018
Once the download is complete, open a directory in which you saved it. Right click to testdisk-7.0.win and select Extract all. Follow the prompts. Next please open the testdisk-7.0 folder as shown on the screen below.
Double click on qphotorec_win to run PhotoRec for Windows. It’ll show a screen as on the image below.
Choose a drive to recover like below.
You will see a list of available partitions. Select a partition that holds encrypted files as on the image below.
Click File Formats button and specify file types to restore. You can to enable or disable the restore of certain file types. When this is finished, press OK button.
Next, click Browse button to choose where restored photos, documents and music should be written, then click Search.
Count of restored files is updated in real time. All restored personal files are written in a folder that you have chosen on the previous step. You can to access the files even if the restore process is not finished.
When the recovery is finished, press on Quit button. Next, open the directory where restored photos, documents and music are stored. You will see a contents as on the image below.
All recovered files are written in recup_dir.1, recup_dir.2 … sub-directories. If you’re looking for a specific file, then you can to sort your recovered files by extension and/or date/time.
How to protect your personal computer from Merl ransomware
Most antivirus programs already have built-in protection system against the ransomware. Therefore, if your computer does not have an antivirus program, make sure you install it. As an extra protection, use the HitmanPro.Alert. It is a small security tool that can detect, remove, and reverse ransomware effects. HitmanPro.Alert can check the system integrity and alerts you when critical system functions are affected by malware.
Visit the page linked below to download HitmanPro Alert. Save it on your Desktop.
Category: Security tools
Update: March 6, 2019
After the downloading process is done, open the file location. You will see an icon like below.
Double click the HitmanPro.Alert desktop icon. Once the utility is started, you will be displayed a window where you can select a level of protection, as displayed below.
Now click the Install button to activate the protection.
This guide was created to help all victims of Merl ransomware virus. We tried to give answers to the following questions: how to remove ransomware; how to decrypt .merl files; how to recover files, if STOP (merl) decryptor does not help; what is an online key and what is an offline key. We hope that the information presented in this manual has helped you.
If you have questions, then write to us, leaving a comment below. If you need more help with Merl related issues, go to here.