How to remove CXK NMSL ransomware from the operating system

Also Known As: CXK NMSL virus
Distribution: Low
Damage level: Severe

CXK NMSL ransomware removal instructions

What is CXK NMSL?

Discovered by Germán Fernández, CXK NMSL is a malicious program classified as ransomware. One method used to distribute this malware is via Corona virus-themed email spam campaigns. Additionally, the malicious executable of CXK NMSL (which initiates the infection) can be similarly disguised (e.g. as "important information" concerning the aforementioned virus). CXK NMSL ransomware is designed to encrypt the data of infected systems and demand a ransom to be paid for decryption. During the encryption process, all affected files are appended with the ".cxk_nmsl" extension. For example, a file originally titled "1.jpg" would appear as "1.jpg.cxk_nmsl" following encryption. After this process is finished, a ransom message in Chinese ("CXK-NMSL-README.txt") is created. Furthermore, CXK NMSL displays various error messages, opens the browser, and redirects to a video on the bilibili video sharing website. It also opens a media player and auto-plays a song.

According to a rough translation, the ransom message informs victims that their data has been encrypted. It also clarifies that the files have been encrypted, but not corrupted. The only method to recover the data is apparently to purchase decryption tools/software from the cyber criminals behind CXK NMSL ransomware. The ransom is 100 B coins (the currency used on the bilibili site). The message contains links to pages detailing what B coins are and from where to purchase them. After the payment is transferred to the criminals' bilibili account, victims are to contact them to confirm the transaction. Additionally, the criminals demand 10 screenshots of Cai Xukun (a Chinese celebrity), the ghost animal video (i.e., the video that is force-opened on the browser, and possibly, other similar videos as well) for three consecutive times. Users are informed that the cyber criminals may not respond immediately, however, they promise to do so when they are available. The message ends with warnings - alerting users not to modify the added extension (i.e. ".cxk_nmsl") and/or otherwise tamper with the encrypted files, as that might damage them beyond repair. In many cases of ransomware infections, decryption is impossible without the involvement of the individuals responsible, unless the malware is still in development and/or has bugs/flaws. Whatever the case, you are strongly advised against meeting the ransom demands. Despite paying, users often receive none of the promised decryption tools/software. Therefore, their data remains encrypted and useless, and they also experience financial loss. To prevent further encryption, remove the malicious CXK NMSL program from the operating system. Unfortunately, removal will not restore already compromised files. The only solution is to recover them from a backup, if one was made before the infection and was stored in a separate location.

Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:

CXK NMSL decrypt instructions (CXK-NMSL-README.txt)

PrometeySDfghjklBadutClowns Team, and Onix are some examples of other ransomware programs. This malicious software is designed to encrypt data and demand payment for decryption. There are several significant differences: the cryptographic algorithm used (symmetric or asymmetric) and ransom size. To protect data from data encryption and damaging infections, keep backups in remote servers and/or unplugged storage devices. Ideally, several backup copies should be stored in multiple different locations.

How did ransomware infect my computer?

CXK NMSL ransomware has been observed spreading through Corona virus-themed email spam campaigns. These deceptive emails infect systems via infectious files attached to (or linked inside) them. Virulent files can be in various formats (e.g. Microsoft Office and PDF documents, archive and executable files, JavaScript, etc.). When opened, the infection process starts. The researched sample of CXK NMSL was distributed in an archived file that contained the malicious executable. The executable is disguised as a Microsoft Office Excel file called "2020.1.10-2020.1.23Information on Travelers from Wuhan China to India.xlsx .exe", however, other disguises/filenames and distribution methods are likely. Aside from spam campaigns, ransomware and other malware proliferates through trojans, illegal activation tools ("cracks"), fake updaters and untrustworthy download channels. Trojans are malicious programs capable of causing chain infections (i.e., download/installation of additional malware). Rather than activating licensed products, illegal activation tools can download/install malicious software. Rogue updaters infect systems by exploiting flaws of outdated programs and/or by simply installing malware rather than the promised updates. Untrusted download sources such as unofficial and free file-hosting websites, Pee-to-Peer sharing networks (BitTorrent, eMule, Gnutella, etc.) and other third party downloaders can offer malicious content by presenting malware as ordinary software or packed with it.

Threat Summary:
Name CXK NMSL virus
Threat Type Ransomware, Crypto Virus, Files locker.
Encrypted Files Extension .cxk_nmsl
Ransom Demand Message CXK-NMSL-README.txt
Ransom Amount 100 B Coins (bilibili)
Cyber Criminal Contact Via cyber criminals' bilibili account
Detection Names Avast (Win32:Evo-gen [Susp]), BitDefender (Gen:Heur.Zilix.1), ESET-NOD32 (Win32/Packed.ASProtect.AAB), Kaspersky (Packed.Win32.Black.d), Full List Of Detections (VirusTotal)
Rogue Process Name Adobe ® Flash ® Player Utility, Message (process name may vary).
Symptoms Cannot open files stored on your computer, previously functional files now have a different extension (for example, my.docx.locked). A ransom demand message is displayed on your desktop. Cyber criminals demand payment of a ransom (usually in bitcoins) to unlock your files.
Additional Information The malware displays various error messages, force-open a video on the bilibili website and plays a song on a media player.
Distribution methods Infected email attachments (macros), torrent websites, malicious ads.
Damage All files are encrypted and cannot be opened without paying a ransom. Additional password-stealing trojans and malware infections can be installed together with a ransomware infection.
Malware Removal (Windows)

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How to protect yourself from ransomware infections

Do not open suspicious or irrelevant emails, especially those received from unknown/suspicious senders (addresses). Never open any attachments or links found in dubious email, as these files are the potential source of an infection. Use only official and verified download channels. Programs should be activated and updated with tools/functions provided by legitimate developers. To ensure device integrity, have a reputable anti-virus/anti-spyware suite installed and kept up to date. Use this software for regular system scans and removal of detected threats/issues. If your computer is already infected with CXK NMSL, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.

Text presented in CXK NMSL ransomware text file ("CXK-NMSL-README.txt"):

Original text:


---=    CXK NMSL! V3.3    =---
hxxps:// #B%E5%B8%81%E7%9B%B8%E5%85% B3?id=669064f15cb84ca5a9ff48081bf00c99
hxxps:// #%E7%A1%AC%E5%B8%81%E7%9B% B8%E5%85%B3?id=0a9b4e2ca5e942b4a565a83390399d0c
| 0. 注册一个帐号 - hxxps://
| 1. 购买B币
| 2. 支付100B币到hxxps://
      hxxps:// #%E5%85%85%E7%94%B5%E8%AE% A1%E5%88%92?id=14cf474095a44dae9a497fba17fa55d7
      然后点击 注意:电池=硬币
| 3. 支付完成后点击进行联系,确认付款成功,并将给10个蔡徐坤鬼畜视频三连的截图发给我。                        
| 4. 由于我不是时刻在线,所以付款完成和发完消息之后请等待回复。
---=    END    =---


Rough English translation:


--- = CXK NMSL! V3.3 = ---
The files on your computer are encrypted! ------
Documents, pictures, videos, audio, compressed files on your computer ... almost all types of files are extorted by cxk-nmsl!
The software is encrypted and cannot be opened normally. This is fundamentally different from a corrupted file. You can find it online
Find a way to recover files, I can guarantee that without me to help you decrypt, even if Cai Xukun is here, I ca n’t recover your text
How do I decrypt these files? ------
Only I can help you decrypt your files, but there is a fee. You need to buy my decryptor and use it to scan
Trace and decrypt files on your computer.
Price and payment method. ------
I will only accept B coins. If you do not understand what B coins are or do not know how to buy B coins, please go to
hxxps:// #B%E5%B8%81%E7%9B%B8% E5%85%B3?id=669064f15cb84ca5a9ff48081bf00c99
You need to pay 100B coins, and give three consecutive 10 Cai Xukun ghost animal videos on bilibili to decrypt your files.
By the way, Sanlian likes, coins and collects. Putting coins is rewarding coins, which is two concepts with B coin.
If you do n’t understand what a coin is or how to get it, go to
hxxps:// #%E7%A1%AC%E5%B8%81%E7%9B%B8% E5%85%B3?id=0a9b4e2ca5e942b4a565a83390399d0c
Payment methods
| 0. Sign up for an account-hxxps://
| 1. Buy B Coins
| 2. Pay 100B coins to hxxps://
      Note, please pay by "charging", if you do n’t know how to do it, go to
      hxxps:// #%E5%85%85%E7%94%B5%E8%AE%A1% E5%88%92?id=14cf474095a44dae9a497fba17fa55d7
      Then click Note: battery = coin
3. After the payment is completed, click to contact, confirm the payment is successful, and send me screenshots of 10 Cai Xukun ghost animal videos for three consecutive times.
| 4. Since I am not always online, please wait for a reply after the payment is completed and the message is sent.
note! ------
Do not modify the file extension and file content, as this may damage the file.
So please do not try.
--- = END = ---

Screenshot of the video on bilibili opened by CXK NMSL ransomware:

bilibili website opened by CXK NMSL ransomware

Screenshot of the media player playing the song, which is opened by CXK NMSL ransomware:

CXK NMSL ransomware media player

Screenshot of CXK NMSL ransomware process in Windows Task Manager ("Adobe ® Flash ® Player Utility"):

CXK NMSL ransomware process on task manager (Adobe ® Flash ® Player Utilit process)

Screenshot of files encrypted by CXK NMSL ransomware (".cxk_nmsl" extension):

Files encrypted by CXK NMSL ransomware (.cxk_nmsl extension)

Update 20 February 2020 - Criminals have recently released an updated version of CXK NMSL ransomware. The behavior of this version is virtually identical - the only difference is that it now changes the victim's desktop wallpaper.

Screenshot of CXK NMSL desktop wallpaper:

CXK NMSL ransomware desktop wallpaper

Screenshot of this variant's process ("Message") in Windows Task Manager:

CXK NMSL ransomware in Windows Task Manager

CXK NMSL ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Malwarebytes is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
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Quick menu:

Isolating the infected device:

Some ransomware-type infections are designed to encrypt files within external storage devices, infect them, and even spread throughout the entire local network. For this reason, it is very important to isolate the infected device (computer) as soon as possible.

Step 1: Disconnect from the internet.

The easiest way to disconnect a computer from the internet is to unplug the Ethernet cable from the motherboard, however, some devices are connected via a wireless network and for some users (especially those who are not particularly tech-savvy), disconnecting cables may seem troublesome. Therefore, you can also disconnect the system manually via Control Panel:

  • Navigate to the "Control Panel", click the search bar in the upper-right corner of the screen, enter "Network and Sharing Center" and select search result:

Disconnecting computer from the Internet (step 1)

  • Click the "Change adapter settings" option in the upper-left corner of the window:

Disconnecting computer from the Internet (step 2)

  • Right-click on each connection point and select "Disable". Once disabled, the system will no longer be connected to the internet. To re-enable the connection points, simply right-click again and select "Enable".

Disconnecting computer from the Internet (step 3)

Step 2: Unplug all storage devices.

As mentioned above, ransomware might encrypt data and infiltrate all storage devices that are connected to the computer. For this reason, all external storage devices (flash drives, portable hard drives, etc.) should be disconnected immediately, however, we strongly advise you to eject each device before disconnecting to prevent data corruption:

  • Navigate to "My Computer", right-click on each connected device and select "Eject":

Ejecting external storage devices

Step 3: Log-out of cloud storage accounts.

Some ransomware-type might be able to hijack software that handles data stored within "the Cloud". Therefore, the data could be corrupted/encrypted. For this reason, you should log-out of all cloud storage accounts within browsers and other related software. You should also consider temporarily uninstalling the cloud-management software until the infection is completely removed.

Identify the ransomware infection:

To properly handle an infection, one must first identify it. Some ransomware infections use ransom-demand messages as an introduction (see the WALDO ransomware text file below).

Identify ransomware-type infection (step 1)

This, however, is rare. In most cases, ransomware infections deliver more direct messages simply stating that data is encrypted and that victims must pay some sort of ransom. Note that ransomware-type infections typically generate messages with different file names (for example, "_readme.txt", "READ-ME.txt", "DECRYPTION_INSTRUCTIONS.txt", "DECRYPT_FILES.html", etc.). Therefore, using the name of a ransom message may seem like a good way to identify the infection. The problem is that most of these names are generic and some infections use the same names, even though the delivered messages are different and the infections themselves are unrelated. Therefore, using the message filename alone can be ineffective and even lead to permanent data loss (for example, by attempting to decrypt data using tools designed for different ransomware infections, users are likely to end up permanently damaging files and decryption will no longer be possible even with the correct tool).

Another way to identify a ransomware infection is to check the file extension, which is appended to each encrypted file. Ransomware infections are often named by the extensions they append (see files encrypted by Qewe ransomware below).

Identify ransomware-type infection (step 2)

This method is only effective, however, when the appended extension is unique - many ransomware infections append a generic extension (for example, ".encrypted", ".enc", ".crypted", ".locked", etc.). In these cases, identifying ransomware by its appended extension becomes impossible.

One of the easiest and quickest ways to identify a ransomware infection is to use the ID Ransomware website. This service supports most existing ransomware infections. Victims simply upload a ransom message and/or one encrypted file (we advise you to upload both if possible).

Identify ransomware-type infection (step 3)

The ransomware will be identified within seconds and you will be provided with various details, such as the name of the malware family to which the infection belongs, whether it is decryptable, and so on.

Example 1 (Qewe [Stop/Djvu] ransomware):

Identify ransomware-type infection (step 4)

Example 2 (.iso [Phobos] ransomware):

Identify ransomware-type infection (step 5)

If your data happens to be encrypted by a ransomware that is not supported by ID Ransomware, you can always try searching the internet by using certain keywords (for example, ransom message title, file extension, provided contact emails, cryptowallet addresses, etc.).

Search for ransomware decryption tools:

Encryption algorithms used by most ransomware-type infections are extremely sophisticated and, if the encryption is performed properly, only the developer is capable of restoring data. This is because decryption requires a specific key, which is generated during the encryption. Restoring data without the key is impossible. In most cases, cyber criminals store keys on a remote server, rather than using the infected machine as a host. Dharma (CrySis), Phobos, and other families of high-end ransomware infections are virtually flawless, and thus restoring data encrypted without the developers' involvement is simply impossible. Despite this, there are dozens of ransomware-type infections that are poorly developed and contain a number of flaws (for example, the use of identical encryption/decryption keys for each victim, keys stored locally, etc.). Therefore, always check for available decryption tools for any ransomware that infiltrates your computer.

Finding the correct decryption tool on the internet can be very frustrating. For this reason, we recommend that you use the No More Ransom Project and this is where identifying the ransomware infection is useful. The No More Ransom Project website contains a "Decryption Tools" section with a search bar. Enter the name of the identified ransomware, and all available decryptors (if there are any) will be listed.

Searching for ransomware decryption tools in website

Restore files with data recovery tools:

Depending on the situation (quality of ransomware infection, type of encryption algorithm used, etc.), restoring data with certain third-party tools might be possible. Therefore, we advise you to use EaseUS Data Recovery Wizard Pro. This tool supports over a thousand data types (graphics, video, audio, documents, etc.) and it is very intuitive (little knowledge is necessary to recover data).

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EaseUS Data Recovery Wizard Pro

By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Trial version of EaseUS Data Recovery Wizard Pro is capable of scanning drives and listing recoverable files - to restore them, you must purchase a license.

Step 1: Perform a scan.

  • Hover your mouse over the partition you wish to scan and select "Scan". You can also select a specific folder, or click shortcut icons to scan the Desktop or Recycle Bin:

Scanning the storage drive with EaseUS Data Recovery Wizard PRO (step 1)

  • Wait for EaseUS Data Recovery Wizard Pro to complete the scan. The scanning duration depends on the volume of files (both in quantity and size) that you are scanning (for example, several hundreds gigabytes could take over an hour to scan). Therefore, be patient during the scanning process. We also advise against modifying or deleting existing files, since this might interfere with the scan. If you add additional data (for example, downloading files/content) while scanning, this will prolong the process:

Scanning the storage drive with EaseUS Data Recovery Wizard PRO (step 2)

Step 2: Recover data.

  • Once the process is complete, select the folders/files you wish to restore and simply click "Recover". Note that some free space on your storage drive is necessary to restore data. Note also that the trial version of EaseUS Data Recovery Wizard Pro is only capable of scanning drives and listing recoverable files - to restore them, you must purchase a license:

Recovering data with EaseUS Data Recovery Wizard Pro

Step 3: Save the scan session (optional).

  • We recommend that you save the scanning session once you have completed recovery, in case you decide to recover additional files later. Simply click the "Save Scan Session" icon in the upper-right corner of the screen and choose the location for the file to be saved. This will save a lot of time, since you will not need to re-scan the storage drive the next time you wish to restore something. Bear in mind, however, that data removed after the scanning session has finished will not be listed:

Saving scan session in EaseUS Data Recovery Wizard Pro

Create data backups:

Proper file management and creating backups is essential for data security. Therefore, always be very careful and think ahead.

Partition management: We recommend that you store your data in multiple partitions and avoid storing important files within the partition that contains the entire operating system. If you fall into a situation whereby you cannot boot the system and are forced to format the disk on which the operating system is installed (in most cases, this is where malware infections hide), you will lose all data stored within that drive. This is the advantage of having multiple partitions: if you have the entire storage device assigned to a single partition, you will be forced to delete everything, however, creating multiple partitions and allocating the data properly allows you to prevent such problems. You can easily format a single partition without affecting the others - therefore, one will be cleaned and the others will remain untouched, and your data will be saved. Managing partitions is quite simple and you can find all necessary information on Microsoft's documentation web page.

Data backups: The most reliable backup method is to use an external storage device and keep it unplugged. Copy your data to an external hard drive, flash (thumb) drive, SSD, HDD, or any other storage device, unplug it and store it in a dry place away from sun and extreme temperatures. This method is, however, quite inefficient, since data backups and updates need to be made regularly. You can also use a cloud service or remote server. Here, an internet connection is required and there is always the chance of a security breach. Therefore, you should consider using an application to create data backups locally.

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EaseUS Todo Backup

By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for EaseUS Todo Backup. 30 days free trial available.

We recommend using the EaseUS Todo Backup application. The "Home" edition of EaseUS Todo Backup is usually more than adequate for regular users, however, the "Business" edition is more suitable for companies and large computer networks. The EaseUS Todo Backup application provides extensive data protection features. You can easily create backups, and encrypt and compress them for enhanced protection and storage saving purposes. It also allows you to set backup schedules, create bootable devices, and restore the system if a crash occurs. You can easily choose where to store the created backup: locally; uploaded to an external drive; FTP; cloud storage, or elsewhere. In summary, EaseUS Todo Backup is an all-in-one tool, which provides all features required to properly backup your data.

Creating a data backup:

The backup process is virtually identical regardless of the item (file, partition, entire system) you wish to backup. Taking the File Backup feature as an example:

Step 1: Choose which item to backup.

  • Click on the "Menu" icon in the upper-left corner of the screen to reveal the menu and select "File Backup":

Creating data backups with EaseUS Todo Backup tool (step 1)

  • Select the files you want to backup. You can also enter a name and description of the backup that will be created:

Creating data backups with EaseUS Todo Backup tool (step 2)

Step 2: Change the default settings.

The EaseUS Todo Backup application provides a variety of additional options that can be added/modified while creating the backup. For example, you can encrypt data (add a password), select the compression rate (how much the backup should be compressed), performance (how many system resources should be allocated), add an email notification (you receive an email once the process is complete) and so on.

  • To open the options window, click the "Backup options" button in the lower-left corner of the screen:

Creating data backups with EaseUS Todo Backup tool (step 3)

  • Select the settings you want to change and click "Save". You can also reset your changes by clicking "Reset to initial settings":

Creating data backups with EaseUS Todo Backup tool (step 4)

Step 3: Select the backup destination.

As mentioned above, EaseUS Todo Backup allows you to choose where backups are saved - locally or externally.

  • Click the "Browse..." button and select the location you want the backup to be saved:

Creating data backups with EaseUS Todo Backup tool (step 5)

Step 4: Safety measures and process completion.

Depending on the location you have chosen, there are a number of measures you should or should not take. If you are uploading to an internet-connected location (for example, Cloud storage, FTP, etc.), be sure to maintain your internet connection, otherwise you will have to start again. The same applies to external storage devices - do not unplug them until the process is complete.

  • The progress bar displays estimated time remaining until completion. Large backups (hundreds of gigabytes) can take hours to create (depending on storage device speed, internet connection, etc.). Therefore, the application also allows you to optionally choose what the system should do (shut down, sleep or hibernate) once the process has finished:

Creating data backups with EaseUS Todo Backup tool (step 6)

The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups.

About the author:

Tomas Meskauskas

Tomas Meskauskas - expert security researcher, professional malware analyst.

I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats. Contact Tomas Meskauskas.

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Malware activity

Global malware activity level today:

Medium threat activity

Increased attack rate of infections detected within the last 24 hours.

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