How to uninstall sepSys from a computer?

Also Known As: sepSys virus
Distribution: Low
Damage level: Severe

sepSys ransomware removal instructions

What is sepSys?

Like most ransomware-type programs, sepSys encrypts files, modifies their filenames and creates a ransom note. This particular ransomware renames files by appending the ".sepsys" extension to their filenames. For example, it renames a file named "sample.jpg" to "sample.jpg.sepsys", and so forth. It creates a ransom note which is a HTML file named "README.html", this note contains details like price of a decryption tool, instructions on how to purchase it, and some other information.

As stated in the ransom note ("README.html"), sepSys encrypts files with a random key and the only way to decrypt them is to use a decryption tool that can be purchased from its developers for $100. A ransom must be paid in Bitcoins, victims have to transfer $100 in Bitcoins to the provided BTC wallet address. After a payment victims supposed to contact cyber criminals (sepSys's developers) via email address and wait for a decryption tool, and instructions on how to use it. Victims are encouraged to contact them as soon as possible because after some time it will not be possible to decrypt encrypted files anymore (encrypted data will permanently corrupted). Unfortunately, there are no other (and free) tools that could decrypt files encrypted by sepSys, at least not at the moment. In other words, its developers are the only ones who can provide victims a decryption tool. However, it is not recommended to pay these or any ransomware developers, quite often they do not send a decryption tool even after a payment. Simply said, victims who pay a ransom often get scammed. Typically, the only way to recover files without having to pay a ransom/use tools that can be provided only by cyber criminals is to restore them from a backup. It is worthwhile to mention even though removal of ransomware is a must, it will not result in data recovery. That will only prevent ransomware from further encryptions.

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

sepSys decrypt instructions (README.html)

Some other examples of ransomware are MaMo434376, Pxj and Jerry_glanville. Programs of this type are designed to prevent victims from accessing, using their files by encrypting them and to create ransom note with instructions on how to contact cyber criminals, pay for a decryption tool, and/or other details. The main variables usually are size of a ransom and cryptographic algorithm (symmetric or asymmetric) that is used to encrypt victim's files. It is very common that programs of this type encrypt files with a strong encryption algorithm and it is impossible to decrypt them without decryption tools that only their developers have. It becomes possible to decrypt files without their tools only if ransomware is still in a development state, has some vulnerabilities. Unluckily, it does not happen often. As mentioned in the previous paragraph, in most cases the only way to recover files for free is to restore them from a backup. Therefore, it is important to always have data backed up and keep it on a remote server (e.g., Cloud) and/or unplugged storage device.

How did ransomware infect my computer?

Typically, cyber criminals spread malicious programs through emails (spam campaigns), untrustworthy file and software download channels, fake software updating tools, Trojans and unofficial activation tools. It is very common that cyber criminals attempt to proliferate malware by sending malicious files via email. Usually they send emails that contain attachments such as Microsoft Office documents, archive files, PDF documents, executable files like .exe, and JavaScript files. They attempt to trick recipients into opening a file that is attached to their email (or can downloaded through a presented link). If opened, those malicious files install malware. Furthermore, quite often cyber criminals use Peer-to-Peer networks (torrent clients, eMule, etc.), free file hosting, freeware download websites, unofficial pages, third party downloaders and other similar channels as tools to distribute, host malicious files. Operating systems get infected when people open a malicious files that were downloaded through those channels, sources. It is worthwhile to mention that uploaded, included malicious files usually are disguised as regular, harmless. Fake software updating tools usually cause damage by installing malware instead of updates or by to exploiting bugs, flaws of some outdated software that is installed on the operating system. Trojan is a type of malicious software that is often designed to cause chain infections. In other words, if a Trojan is installed on the operating system, then it is very likely that it will install some other malware. Software 'cracking' tools are used by people who seek to activate licensed programs for free. However, tools of this type are often designed to spread distribute (install) various malicious programs, including ransomware-type programs.

Threat Summary:
Name sepSys virus
Threat Type Ransomware, Crypto Virus, Files locker
Encrypted Files Extension .sepsys
Ransom Demanding Message README.html
Ransom Amount $100 in Bitcoins
Bitcoin Wallet Address 3BL1TbL96gQFTR9EJFKX7JSp889oj2nJmj
Cyber Criminal Contact
Detection Names Fortinet (W32/Ransom.FVG!tr), Kaspersky (Trojan.Win32.Zudochka.ebg), Microsoft (Ransom:Win32/SepSys!MTB), Sophos AV (Troj/Ransom-FVG), 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 demand payment of a ransom (usually in bitcoins) to unlock your files.
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.

To eliminate malware infections our security researchers recommend scanning your computer with Spyhunter.
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How to protect yourself from ransomware infections?

If a received email contains attachment (and/or website link), it is sent from unknown and/or suspicious address, then its contents should not be opened. At least not without being sure that it is safe. It is worthwhile to mention such emails often are irrelevant, disguised as important, official. All installed software should be updated only with implemented functions and/or tools that are designed by official software developers. None of the third party updaters should be used for that. Software and files should be downloaded from trustworthy, official websites and via direct links. Third party downloaders, installers, questionable pages and other similar sources, tools are often used to distribute unwanted, potentially malicious software. Unofficial activation ('cracking') tools can lead to installation of malware too. Besides, it is not legal to activate/register licensed software with tools of this type. One more way to keep computers safer is to regularly scan them with a reputable anti-spyware or antivirus software and always remove detected threats as soon as possible. If your computer is already infected with sepSys, we recommend running a scan with Spyhunter for Windows to automatically eliminate this ransomware.

Text presented in sepSys ransomware's ransom note ("README.hmtl"):

ATTENTION! Your computer has been infected by sepSys!
Your files have been encrypted with a random key and no decryption tool can save them

To regain access to your files, please make a $100 donation to Silicon Venom

We only accept payments in Bitcoin (BTC). Check this out to learn more: hxxps://

Your donation should be sent to the following BTC wallet address: 3BL1TbL96gQFTR9EJFKX7JSp889oj2nJmj

Once you have paid, contact us at to receive your unique password and instructions on how to use it

The sooner you pay the better! Your files will be permanently corrupted over time, so act quickly

We appreciate your cooperation.

Screenshot of files encrypted by sepSys (".sepsys" extension):

Files encrypted by sepSys ransomware (.sepsys extension)

sepSys ransomware removal:

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Spyhunter is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
▼ DOWNLOAD Spyhunter By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. Free scanner checks if your computer is infected. To remove malware, you have to purchase the full version of Spyhunter.

Quick menu:

Step 1

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Safe Mode with Networking

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup. Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings". Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Windows 8 Safe Mode with networking

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options". In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

windows 10 safe mode with networking

Video showing how to start Windows 10 in "Safe Mode with Networking":

Step 2

Log in to the account infected with the sepSys virus. Start your Internet browser and download a legitimate anti-spyware program. Update the anti-spyware software and start a full system scan. Remove all entries detected.

If you cannot start your computer in Safe Mode with Networking, try performing a System Restore.

Video showing how to remove ransomware virus using "Safe Mode with Command Prompt" and "System Restore":

1. During your computer start process, press the F8 key on your keyboard multiple times until the Windows Advanced Options menu appears, and then select Safe Mode with Command Prompt from the list and press ENTER.

Boot your computer in Safe Mode with Command Prompt

2. When Command Prompt mode loads, enter the following line: cd restore and press ENTER.

system restore using command prompt type cd restore

3. Next, type this line: rstrui.exe and press ENTER.

system restore using command prompt rstrui.exe

4. In the opened window, click "Next".

restore system files and settings

5. Select one of the available Restore Points and click "Next" (this will restore your computer system to an earlier time and date, prior to the sepSys ransomware virus infiltrating your PC).

select a restore point

6. In the opened window, click "Yes".

run system restore

7. After restoring your computer to a previous date, download and scan your PC with recommended malware removal software to eliminate any remaining sepSys ransomware files.

To restore individual files encrypted by this ransomware, try using Windows Previous Versions feature. This method is only effective if the System Restore function was enabled on an infected operating system. Note that some variants of sepSys are known to remove Shadow Volume Copies of the files, so this method may not work on all computers.

To restore a file, right-click over it, go into Properties, and select the Previous Versions tab. If the relevant file has a Restore Point, select it and click the "Restore" button.

Restoring files encrypted by CryptoDefense

If you cannot start your computer in Safe Mode with Networking (or with Command Prompt), boot your computer using a rescue disk. Some variants of ransomware disable Safe Mode making its removal complicated. For this step, you require access to another computer.

To regain control of the files encrypted by sepSys, you can also try using a program called Shadow Explorer. More information on how to use this program is available here.

shadow explorer screenshot

To protect your computer from file encryption ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and EasySync CryptoMonitor, which artificially implant group policy objects into the registry to block rogue programs such as sepSys ransomware.

Note that Windows 10 Fall Creators Update includes a "Controlled Folder Access" feature that blocks ransomware attempts to encrypt your files. By default, this feature automatically protects files stored in the Documents, Pictures, Videos, Music, Favorites, and Desktop folders.

Controll Folder Access

Windows 10 users should install this update to protect their data from ransomware attacks. Here is more information on how to get this update and add an additional protection layer from ransomware infections.

HitmanPro.Alert CryptoGuard - detects encryption of files and neutralises any attempts without need for user-intervention:

hitmanproalert ransomware prevention application

Malwarebytes Anti-Ransomware Beta uses advanced proactive technology that monitors ransomware activity and terminates it immediately - before reaching users' files:

malwarebytes anti-ransomware

  • The best way to avoid damage from ransomware infections is to maintain regular up-to-date backups. More information on online backup solutions and data recovery software Here.

Other tools known to remove sepSys ransomware:

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.

PCrisk security portal is brought by a company RCS LT. Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.

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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.

QR Code
sepSys virus QR code
A QR code (Quick Response Code) is a machine-readable code which stores URLs and other information. This code can be read using a camera on a smartphone or a tablet. Scan this QR code to have an easy access removal guide of sepSys virus on your mobile device.
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