*.thor Ransomware

Also Known As: Thor virus
Distribution: Low
Damage level: Medium

*.thor ransomware removal instructions

What is *.thor?

*.thor is a new variant of Locky ransomware. Developers spread this ransomware via spam emails. Following infiltration, *.thor encrypts various files using asymmetric cryptography. During encryption, this ransomware renames files using the "[8_random_characters]-[4_random_characters]-[4_random_characters]-[4_random_characters]-[12_random_characters].thor" pattern. For example, the name of an encrypted file might be renamed to "D56F3331-380D-9317-3F9C-6CE2C2BB051.thor". Once files are encrypted, *.thor places two files (.html and .bmp, both named "_WHAT_is") on the desktop and changes the desktop wallpaper.

The .html and .bmp files contain an identical ransom-demand message stating that files are encrypted using RSA-2048 and AES-128 encryption algorithms. The message also states that the files can only be restored using a private key with a decryption tool. As mentioned above, *.thor encrypts files using asymmetric cryptography. Therefore, two keys (public [encryption] and private [decryption]) are generated during encryption. The private key is stored on remote servers owned by cyber criminals. Claims that decryption without this key is impossible are in unfortunately correct. To restore their files, victims must supposedly pay a ransom of 3 Bitcoins (currently equivalent to ~$1952), however, paying does not guarantee that your files will ever be decrypted. Cyber criminals often ignore victims, despite payments made. If you pay, there is a high probability that you will be scammed. Therefore we strongly advise you to ignore all requests to pay or contact these people. Unfortunately, there are currently no tools available to decrypt compromised files free of charge - the only solution is to restore your files/system from a backup.

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

*.thor decrypt instructions

All ransomware-type viruses are virtually identical. As with *.thor, malware such as Cerber, CTB-Locker, and Cry also encrypt files and demand hundreds or even thousands of dollars. There are only two major differences: size of ransom and type of cryptography used (symmetric/asymmetric). Viruses such as *.thor are distributed using spam emails (malicious attachments), peer-to-peer (P2P) networks (for example, Torrent, eMule, etc.), fake software update tools, and trojans. Therefore, be cautious when opening files received from unrecognized/suspicious email addresses and downloading software from unofficial sources. Furthermore, keep your installed software up-to-date - cyber criminals are capable of exploiting software bugs to infiltrate the system. Using a legitimate anti-virus/anti-spyware program is also very important.

Screenshot of *.thor ransomware .bmp file ("_WHAT_is.bmp"):

*.thor ransomware bmp file

Screenshot of *.thor ransomware .html file ("_WHAT_is.html"):

*.thor ransomware html file

Screenshot of *.thor ransomware Tor website:

*.thor ransomware website

Screenshot of files encrypted by *.thor ransomware ("[8_random_characters]-[4_random_characters]-[4_random_characters]-[4_random_characters]-[12_random_characters].thor" pattern):

*.thor ransomware encrypting victim's files

File types targeted by *.thor ransomware:

7zip; .aac; .accdb; .accde; .accdr; .accdt; .ach; .acr; .act; .adb; .adp; .ads; .aes; .agdl; .aiff; .ait; .aoi; .apj; .apk; .ARC; .arw; .asc; .asf; .asm; .asp; .aspx; .asset; .asx; .avi; .awg; .back; .backup; .backupdb; .bak; .bank; .bat; .bay; .bdb; .bgt; .bik; .bin; .bkp; .blend; .bmp; .bpw; .brd; .bsa; .cdf; .cdr; .cdr3; .cdr4; .cdr5; .cdr6; .cdrw; .cdx; .cer; .cfg; .cgm; .cib; .class; .cls; .cmd; .cmt; .config; .contact; .cpi; .cpp; .craw; .crt; .crw; .csh; .csl; .csr; .css; .csv; .CSV; .d3dbsp; .dac; .das; .dat; .db_journal; .dbf; .dbx; .dch; .dcr; .dcs; .ddd; .ddoc; .ddrw; .dds; .der; .des; .design; .dgc; .dif; .dip; .dit; .djv; .djvu; .dng; .doc; .DOC; .docb; .docm; .docx; .dot; .DOT; .dotm; .dotx; .drf; .drw; .dtd; .dwg; .dxb; .dxf; .dxg; .edb; .eml; .eps; .erbsql; .erf; .exf; .fdb; .ffd; .fff; .fhd; .fla; .flac; .flf; .flv; .flvv; .forge; .fpx; .frm; .fxg; .gif; .gpg; .gray; .grey; .groups; .gry; .hbk; .hdd; .hpp; .html; .hwp; .ibank; .ibd; .ibz; .idx; .iif; .iiq; .incpas; .indd; .iwi; .jar; .java; .jnt; .jpe; .jpeg; .jpg; .kdbx; .kdc; .key; .kpdx; .kwm; .laccdb; .lay; .lay6; .lbf; .ldf; .lit; .litemod; .litesql; .log; .ltx; .lua; .m2ts; .mapimail; .max; .mbx; .mdb; .mdc; .mdf; .mef; .mfw; .mid; .mkv; .mlb; .mml; .mmw; .mny; .moneywell; .mos; .mov; .mpeg; .mpg; .mrw; .ms11 (Security copy); .msg; .myd; .MYD; .MYI; .ndd; .ndf; .nef; .NEF; .nop; .nrw; .nsd; .nsf; .nsg; .nsh; .nvram; .nwb; .nxl; .nyf; .oab; .obj; .odb; .odc; .odf; .odg; .odm; .odp; .ods; .odt; .ogg; .oil; .onetoc2; .orf; .ost; .otg; .oth; .otp; .ots; .ott; .pab; .pages; .PAQ; .pas; .pat; .pcd; .pct; .pdb; .pdd; .pdf; .pef; .pem; .pfx; .php; .pif; .plc; .plus_muhd; .png; .pot; .potm; .potx; .ppam; .pps; .ppsm; .ppsx; .ppt; .PPT; .pptm; .pptx; .prf; .psafe3; .psd; .pspimage; .pst; .ptx; .pwm; .qba; .qbb; .qbm; .qbr; .qbw; .qbx; .qby; .qcow; .qcow2; .qed; .raf; .rar; .rat; .raw; .rdb; .rtf; .RTF; .rvt; .rwl; .rwz; .s3db; .safe; .sas7bdat; .sav; .save; .say; .sch; .sda; .sdf; .sldm; .sldx; .slk; .sql; .sqlite; .sqlite3; .SQLITE3; .sqlitedb; .SQLITEDB; .srf; .srt; .srw; .stc; .std; .sti; .stm; .stw; .stx; .svg; .swf; .sxc; .sxd; .sxg; .sxi; .sxm; .sxw; .tar; .tarbz2; .tbk; .tex; .tga; .tgz; .thm; .tif; .tiff; .tlg; .txt; .uop; .uot; .upk; .vbox; .vbs; .vdi; .vhd; .vhdx; .vmdk; .vmsd; .vmx; .vmxf; .vob; .wab; .wad; .wallet; .wav; .wks; .wma; .wmv; .wpd; .wps; .xis; .xla; .xlam; .xlc; .xlk; .xlm; .xlr; .xls; .XLS; .xlsb; .xlsm; .xlsx; .xlt; .xltm; .xltx; .xlw; .xml; .ycbcra; .yuv; .zip

*.thor 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:

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 *.thor 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 *.thor 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 *.thor 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 *.thor 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 *.thor, 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 encrypting ransomware such as this, use reputable antivirus and anti-spyware programs. As an extra protection method, you can use programs called HitmanPro.Alert and Malwarebytes Anti-Ransomware, which artificially implant group policy objects into the registry to block rogue programs such as *.thor ransomware.)

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 *.thor 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 pcrisk.com 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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Removal Instructions in other languages
Malware activity

Global malware activity level today:

Medium threat activity

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

QR Code
Thor 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 Thor virus on your mobile device.
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