SDEN ransomware removal instructions
What is SDEN?
SDEN is a ransomware-type infection discovered by Petrovic and belonging to the Matrix ransomware family. This malware is designed to infiltrate the system and encrypt most stored files using AES-128 and RSA-2048 encryption algorithms. In doing so, SDEN renames each file using the "[developer's_email].[unique_ID].SDEN" pattern. For example, "sample.jpg" might be renamed to a filename such as "[SmartDen@protonmail.com].qpnrZUKL-5Hx3ICAB.SDEN". Once encrypted, data becomes unusable and indistinguishable. This malware also places the "!SDEN_INFO!.rtf" file on the desktop.
The new .rtf file contains a ransom-demand message, which essentially states that data is encrypted using AES-128 and RSA-2048 encryptions and can only be restored using a decryption key/tool. Unfortunately, this information is accurate. Both AES and RSA algorithms generate a unique decryption key for each victim. Recovery without these keys is impossible. Cyber criminals store them on a remote server to blackmail victims - the message states that each victim must pay a ransom (in Bitcoins) to retrieve the files. The cost is not specified - all details are provided via email, however, in most cases, the cost fluctuates between $500 and $1500. Regardless of the cost, do not pay. Research shows that ransomware developers ignore victims, once payments are submitted. Therefore, paying usually gives no positive result and users are scammed. You are advised to ignore all requests to submit payments or contact these people. Unfortunately, there are no tools capable of cracking SDEN encryption and restoring data free of charge. The only solution is to restore everything from a backup.
Screenshot of a message encouraging users to pay a ransom to decrypt their compromised data:
SDEN shares many similarities with dozens of other ransomware-type infections including SadComputer, Browec, and Guvara. Although the developers may differ, most of these infections have identical behavior: they compromise data (typically, by encryption) and make ransom demands in exchange for file recovery. Such infections typically employ cryptographies that generate unique decryption keys. Therefore, unless the virus is not fully developed or has certain bugs/flaws, restoring data manually without involvement of developers (contacting these people is not recommended) is impossible. Ransomware is one of the main reasons why you should maintain regular backups, however, store them on a remote server (e.g., Cloud) or unplugged storage device (Flash drive, external hard drive, or similar). Locally stored backups are damaged together with regular data.
How did ransomware infect my computer?
It is currently unknown exactly how developers proliferate SDEN. Nevertheless, malware of this type is usually proliferated using the following tools/methods: trojans, fake software updaters and 'cracks', spam email campaigns, and unofficial software download sources. Trojans are essentially malicious applications that stealthily infiltrate computers and inject them with additional malware. To infect computers, fake updaters exploit outdated software bugs/flaws or simply download and install malware rather than updates. Cracks work in a similar manner. Although their purpose is to activate paid software free of charge, cyber criminals often use them to proliferate malware, and thus users are much more likely to infect their computers than gain access to paid features. Cyber criminals send hundreds of thousands of email message that contain malicious attachments. The messages encouraging users to open the attachments, which are typically presented as "important documents" (e.g., invoices, bills, receipts, etc.). These claims are merely attempts to give the impression of legitimacy and trick users into opening files, thereby leading to system infection. Finally, unofficial software download sources are used when presenting malicious executables as legitimate software - users are tricked into downloading and installing malware manually.
|Threat Type||Ransomware, Crypto Virus, Files locker.|
|Encrypted Files Extension||.SDEN (this ransomware replaces the entire filename using "[developer's_email].[unique_ID].SDEN" pattern).|
|Ransom Demanding Message||!SDEN_INFO!.rtf file|
|Cyber Criminal Contactfirstname.lastname@example.org, email@example.com, firstname.lastname@example.org|
|Detection Names (m.exe)||Avast (Win32:Trojan-gen), BitDefender (Generic.Ransom.Matrix.CDD86710), ESET-NOD32 (a variant of Win32/Filecoder.LockedFile.I), Kaspersky (HEUR:Trojan-Ransom.Win32.Agent.gen), Full List Of Detections (VirusTotal)|
|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 request payment of a ransom (usually in Bitcoins) to unlock your files.|
|Additional Information||Encrypts data using AES-128 and RSA-2048 encryption algorithms.|
|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)||
To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Malwarebytes.
How to protect yourself from ransomware infections?
The main reasons for computer infections are poor knowledge and careless behavior. Caution is the key to safety. Therefore, pay close attention when browsing the internet and downloading, installing, and updating software. Think twice before opening email attachments. Files/links that are irrelevant and those received from suspicious/unrecognizable email addresses should never be opened. Download software from official sources only, using direct download links. Third party software donwloaders/installers should never be used. Similar rules apply to software updates. It is important to keep installed apps and operating systems up-to-date, however, this should be achieved through implemented functions or tools provided by the official developer. Software piracy is a cyber crime and the risk of infection is extremely high. Therefore, never attempt to crack installed applications. Use a reputable anti-virus/anti-spyware suite. These tools detect and eliminate malware before it damages the system. If your computer is already infected with SDEN, we recommend running a scan with Malwarebytes for Windows to automatically eliminate this ransomware.
The appearance of SDEN ransomware "!SDEN_INFO!.rtf" file (GIF):
Ransom-demand message presented within this file:
HOW TO RECOVER YOUR FILES?
WE HAVE TO INFORM YOU THAT ALL YOUR FILES WERE ENCRYPTED!
PLEASE BE SURE THAT YOUR FILES ARE NOT BROKEN!
Your files were encrypted with AES-128+RSA-2048 crypto algorithms.
* Please note that there is no way to decrypt your files without unique decryption key and special software. Your unique decryption key is securely stored on our server.
* Please note that all the attempts to recover your files by yourself or using third party tools will result only in irrevocable loss of your data!
* Please note that you can recover files only with your unique decryption key, which stored on our server.
HOW TO RECOVER FILES?
Please write us to the e-mail, we will send you instruction how to recover your data.
Our main e-mail: SmartDen@protonmail.com
Our secondary e-mail: SmartDen@tutanota.com
Our secondary e-mail: SmartDen@india.com
Please write to our main e-mail. If you will not receive answer in 24 hours, please write to our secondary e-mails! Please always check SPAM folder!
* Write on English or use professional translator
In subject line write your personal ID: 150938D204D4C59E
For your assurance you can attach up to 3 small encrypted files to your message. We will decrypt and send you decrypted files for free.
* Please note that files must not contain any valuable information and their total size must be less than 5Mb.
Please don't worry, we can help you to RESTORE your server to original
state and decrypt all your files quickly and safely!
You have to pay for our help in Bitcoin Cryptocurrency.
Immidiately after payment we will send you (by e-mail) automatic decryption tool and your unique decryption key. You just have to start decryption tool on your server and all files will be automatically decrypted. All original file names will be restored too.
Screenshot of files encrypted by SDEN ("[developer's_email].[unique_ID].SDEN" filename pattern):
SDEN 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:
- What is SDEN virus?
- STEP 1. Isolating the infected device.
- STEP 2. Identifying the ransomware infection.
- STEP 3. Searching for ransomware decryption tools.
- STEP 4. Restoring files with data recovery tools.
- STEP 5. Creating data backups.
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:
Click the "Change adapter settings" option in the upper-left corner of the window:
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".
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":
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).
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).
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).
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):
Example 2 (.iso [Phobos] ransomware):
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.
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).
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:
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:
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:
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:
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.
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":
Select the files you want to backup. You can also enter a name and description of the backup that will be created:
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:
Select the settings you want to change and click "Save". You can also reset your changes by clicking "Reset to initial settings":
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:
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:
The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups.