What is Koom virus?
Koom virus is a new ransomware that belongs to the family of ransomware called STOP (Djvu). Ransomware is a form of malware that encrypts the victim’s files and demands a ransom for decrypting them. The Koom virus encrypts files, renames them by appending the .koom extension, and creates files named “_readme.txt” containing the ransom demand message. For example, a file named “image.jpg” will be renamed to “image.jpg.koom”, a “document.docx” file to “document.docx.koom”, “invoice.pdf” to “invoice.pdf.koom”, and so on.
Screenshot of files encrypted by Koom virus (‘.koom’ file extension)
QUICK LINKS
- What is Koom virus?
- Remove Koom virus (ransomware)
- Decrypt .koom files
- Restore .koom files
- Video Guide
Koom ransomware is a malware which is a new variant of STOP ransomware. Like other variants, it encrypts all files on the computer and then demands a ransom for decryption. This virus encrypts files using a strong encryption method, which eliminates the possibility of finding a key in any way. For each victim, Koom uses a unique key with a small exception. If the virus cannot establish a connection with its command and control server (C&C) before starting the encryption process, then it uses an offline key. This key is the same for any victims, which makes it possible in some cases to decrypt files that were encrypted during the ransomware attack.
Koom has the ability to encrypt files of any type, regardless of what is in them. But it skips files with the extension: .ini, .dll, .lnk, .bat, .sys and files named ‘_readme.txt’. Thus, the following common file types can be easily encrypted:
.x, .wri, .zif, .zdb, .wpw, .iwi, .vpp_pc, .0, .iwd, .vdf, .jpg, .bay, .p7c, .xll, .ff, .zip, .cfr, .cer, .flv, .wbm, .w3x, .rwl, .icxs, .mdbackup, .wsc, .xdb, .ppt, .itm, .arw, .fos, .mcmeta, .wbmp, .wire, .wgz, .xf, .wsd, .itdb, .tor, .blob, .wma, .arch00, .sis, .ptx, .esm, .odt, .wps, .raw, .odc, .layout, .ai, .sum, .orf, .wdb, .wp7, .mdf, .ntl, .dng, .mdb, .forge, .xlsx, .xbplate, .mp4, .ztmp, .pptm, .wpt, .db0, .wps, .m2, .csv, .pak, .lbf, .accdb, .z3d, .2bp, .py, .itl, .rb, .xar, .hkdb, .cr2, .avi, .wp, .vpk, .png, .wp5, .p12, .xyw, .xml, .bc7, .xlsm, .rofl, .pdf, .sie, .mrwref, .dxg, .wmo, .psd, .mov, .pem, .bc6, .sb, .tax, .bkf, .wotreplay, .epk, .z, .rtf, .zip, .mlx, .wp6, .hplg, .3dm, .kdc, .wbk, .xy3, .fsh, .wdp, .qdf, .t13, .m4a, .wp4, .d3dbsp, .xxx, .zabw, .rar, .desc, .sid, .kf, .css, .wb2, .ybk, .das, .wcf, .xlk, .pfx, .bar, .dmp, .wpl, .dba, .xdl, .big, .sav, .eps, .odm, .pptx, .wmf, .sidd, .p7b, .wpa, .erf, .lvl, .xpm, .nrw, .mddata, .raf, .dbf, .t12, .webp, .crw, .dwg, .ltx, .x3f, .rgss3a, .slm, .doc, .wsh, .yal, .xbdoc, .pkpass, .xls, .xlsb, .xmind, .psk, .mpqge, .dazip, .svg, .srf, .xlgc, .vfs0
Each file that has been encrypted will be renamed. This means the following. If the file was called ‘document.docx’, then after encryption, it will be named ‘document.docx.koom’. Koom virus can encrypt files located on all drives connected to the computer. Therefore, files located in network attached storage and external devices can also be encrypted. It encrypts file by file, when all the files in the directory are encrypted, it drops a new file in the directory, which is called ‘_readme.txt’. Below is the contents of this file.
Screenshot of the contents of ‘_readme.txt’ file (Koom ransom note)
This file is present in all directories with encrypted files. But the contents of this file are the same everywhere. This file contains a message from Koom creators. In this message, the criminals report that all the files were encrypted and the only way to decrypt them is to buy a decryptor and key. Attackers demand a ransom of $490, if the victim does not pay the ransom within 72 hours, then the ransom will double to $980. Koom authors left two email addresses that the victim must use to contact them. To confirm the possibility of decryption, criminals offer to decrypt one file that does not contain important information for free. But it’s obvious that there is no guarantee that even by paying the ransom, the victim will be able to decrypt all files that have been encrypted.
Text presented in the ransom note:
ATTENTION!
Don’t worry, you can return all your files!
All your files like pictures, databases, documents and other important are encrypted with strongest encryption and unique key.
The only method of recovering files is to purchase decrypt tool and unique key for you.
This software will decrypt all your encrypted files.
What guarantees you have?
You can send one of your encrypted file from your PC and we decrypt it for free.
But we can decrypt only 1 file for free. File must not contain valuable information.
You can get and look video overview decrypt tool:
https://we.tl/t-vtoEIhR0SI
Price of private key and decrypt software is $980.
Discount 50% available if you contact us first 72 hours, that’s price for you is $490.
Please note that you’ll never restore your data without payment.
Check your e-mail “Spam” or “Junk” folder if you don’t get answer more than 6 hours.To get this software you need write on our e-mail:
manager@mailtemp.chReserve e-mail address to contact us:
managerhelper@airmail.ccYour personal ID:
0334xxxxxxxx
Threat Summary
| Name | Koom ransomware, Koom file virus |
| Type | Ransomware, Crypto malware, File locker, Filecoder, Crypto virus |
| File extension | .koom |
| Ransom note | _readme.txt |
| Contact | helpteam@mail.ch, helpmanager@airmail.cc |
| Ransom amount | $980/$490 in Bitcoins |
| Detection Names | Trojan/Win.Glupteba.R421575, Win32:PWSX-gen [Trj], Trojan.GenericKD.46322797, Trojan.PWS.Siggen2.62683, PossibleThreat.PALLAS.H, HEUR:Trojan-Ransom.Win32.Stop.gen, Trojan:Win32/Glupteba.QB!MTB, Trojan.Win32.Save.a, ML.Attribute.HighConfidence, Win32.Trojan.Raas.Auto |
| Symptoms | When you try to open your file, Windows notifies that you do not have permission to open this file. Odd, new or missing file extensions. Files named such as ‘_readme.txt’, ‘READ-ME’, ‘_open me’, _DECRYPT YOUR FILES’ or ‘_Your files have been encrypted” in every folder with an encrypted file. New files on your desktop, with name variants of: ‘HOW_TO_DECRYPT.txt’, ‘DECRYPT.txt’ or ‘README.txt’. |
| Distribution methods | Malicious spam (also known as ‘malspam’). Drive-by downloading (when a user unknowingly visits an infected web-page and then malware is installed without the user’s knowledge). Social media, such as web-based instant messaging applications. USB flash drive and other removable media. |
| Removal | Koom virus removal guide |
| Decryption | Koom File Decrypt Tool |
Koom authors scare victims by saying that encrypted files cannot be decrypted without paying a ransom. And unfortunately this is true, the contents of the files cannot be read while the files are encrypted, and a key and decryptor are needed to decrypt them.
Fortunately, there is a free decryptor (Koom File Decrypt Tool) that can decrypt encrypted files in some cases. It can help each victim to decrypt .koom files for free. But in addition to the decryptor, the key is still necessary. As we reported above, the ransomware can use two types of keys. Only files encrypted with the offline key can be decrypted, and only after security researchers have obtained the offline key. Files that have been encrypted with so called ‘online key’ cannot yet be decrypted. In any case, there are several more universal methods for recovering encrypted files, which will be demonstrated below. It is very important to read the entire instruction manual carefully and make sure to understand it all. We advise you not to skip any steps, each of the steps is very important and must be completed by you. In order not to get confused and not miss an important point in the instructions, we recommend that you print this article or open it on your smartphone.
How to remove Koom virus (ransomware)
Before you start decrypting or recovering .koom files, you need to remove Koom ransomware and its autostart entries. This must be done since otherwise the ransomware may re-encrypt the restored files. You can stop the ransomware from working, as it is not difficult to do. Another option is to perform a full system scan using free malware removal tools capable of detecting and removing ransomware infection.
It is very important to scan the computer for malware, as security researchers found that spyware could be installed on the infected computer along with the Koom ransomware. Spyware is a very dangerous security threat as it is designed to steal the user’s personal information such as passwords, logins, contact details, etc. If you have any difficulty removing the Koom virus, then let us know in the comments, we will try to help you.
To remove Koom ransomware, follow the steps below:
Kill Koom virus
Press CTRL, ALT, DEL keys together.
Click Task Manager. Select the “Processes” tab, look for something suspicious that is the Koom ransomware then right-click it and select “End Task” or “End Process” option. If your Task Manager does not open or the Windows reports “Task manager has been disabled by your administrator”, then follow the guide: How to Fix Task manager has been disabled by your administrator.
It is not difficult to detect a process related to the Koom ransomware. When looking for a malicious process, pay attention to the process icon and its name. Most often, this ransomware has a process name in the following format: 4-characters.tmp.exe or 4-characters.exe. For example: 7533.tmp.exe, A4b1.exe, CD15.tmp.exe, 19b2.exe. The process name can also contain “(32 bit)”. If you do not find a process with a similar name in the list of processes, then most likely the Koom ransomware has finished working. But keep in mind, if you do not remove the ransomware autostart entries, as demonstrated below, and do not delete its file, then after a while it may start again, and if it finds unencrypted files, immediately encrypt them.
Disable Koom Start-Up
Select the “Start-Up” tab, look for something similar to the one shown in the example below, right click to it and select Disable.
Close Task Manager.
Delete Koom Task
Type “Task Scheduler” in the search bar. Click Task Scheduler app in the search results. Click “Task Scheduler Library” in the left panel. On the right panel, right-click to “Time Trigger Task” and select Delete.
Close Task Scheduler.
Remove Koom virus
Run Task Manager and select the “Start-Up” tab. Right click to the Koom ransomware Start-Up entry and select Open File Location as shown below.
A directory containing one file will open in front of you, this file is the Koom virus. It needs to be removed. If you try to delete it immediately, then you will not succeed, since this file is protected from deletion.
To delete this file, you need to do the following. Right-click on the file, select Properties. In the window that opens, select Security tab. Next, click the Advanced button below. A window will open as shown in the following example.
Click Disable inheritance. In the Block inheritance dialog box that opens, select the first item (Convert inherited permissions…) as shown below.
In the Permission entries list, select “Deny Everyone”, click Remove button and then OK. Close the file properties window. You should now be able to remove the Koom virus. Right-click on the file and select Delete.
Scan computer for malware
Zemana Anti-Malware (ZAM) is a malware removal tool that performs a scan of a computer and displays if there are existing ransomware, adware, spyware, trojans, worms and other malicious software residing on your computer. If malware is found, Zemana can automatically remove it. Zemana Anti Malware does not conflict with other antimalware and antivirus programs installed on your PC.
Visit the following page to download Zemana installer on your PC. Save it to your Desktop.
164029 downloads
Author: Zemana Ltd
Category: Security tools
Update: July 16, 2019
Launch the install package after it has been downloaded successfully and then follow the prompts to install this tool on your PC system.
During install you can change certain settings, but we advise you do not make any changes to default settings.
When install is done, this malicious software removal tool will automatically start and update itself. You will see its main window as displayed in the figure below.
Now press the “Scan” button to perform a system scan for the Koom ransomware, other kinds of potential threats such as spyware and trojans. A scan can take anywhere from 10 to 30 minutes, depending on the number of files on your personal computer and the speed of your computer. While the Zemana program is scanning, you can see count of objects it has identified as threat.
As the scanning ends, Zemana Anti-Malware will open a list of security threats found by the scan. Make sure all threats have ‘checkmark’ and click “Next” button.
Zemana Anti Malware will start to remove Koom ransomware, other malicious software, worms and trojans. Once finished, you can be prompted to restart your device to make the change take effect.
In order to be 100% sure that the computer no longer has the Koom virus, we recommend using the Kaspersky virus removal tool (KVRT). It is free and easy to use. It can scan and remove ransomware, spyware, potentially unwanted applications, worms, trojans, adware and other malware. KVRT is powerful enough to find and uninstall malicious registry entries and files that are hidden on the machine.
Download Kaspersky virus removal tool from the following link. Save it to your Desktop.
129055 downloads
Author: Kaspersky® lab
Category: Security tools
Update: March 5, 2018
When downloading is finished, double-click on the Kaspersky virus removal tool icon. Once initialization process is finished, you will see the KVRT screen as shown in the figure below.
Click Change Parameters and set a check near all your drives. Press OK to close the Parameters window. Next click Start scan button . KVRT tool will begin scanning the whole PC to detect the Koom ransomware. This procedure can take some time, so please be patient.
When Kaspersky virus removal tool has completed scanning, it will open the Scan Results like below.
Review the results once the utility has finished the system scan. If you think an entry should not be quarantined, then uncheck it. Otherwise, simply click on Continue to begin a cleaning process.
How to decrypt .koom files
All files with the ‘.koom’ extension are encrypted. Their contents cannot be unlocked simply by removing this extension or completely changing the filename. To decrypt .koom files, you need a decryptor. Fortunately, there is a free Koom File Decrypt Tool that can decrypt .koom files. Below we provide instructions on where to download and how to use Koom File Decrypt Tool.
Koom File Decrypt Tool (STOP Djvu decryptor)
To decrypt .koom files, use Koom File Decrypt Tool
- Download Koom File Decrypt Tool 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.
Koom File Decrypt Tool is a free tool that allows everyone to decrypt .koom files for free. At the moment, the decryptor can only decrypt files that have been encrypted with an offline key. Unfortunately, if the files were encrypted with an online key, then the free decryptor is completely useless. In this case, 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
Since Koom File Decrypt Tool only decrypts files encrypted with the offline key, each Koom’s victim needs to find out which key was used to encrypt the files. Determining the type of key used is not difficult. Below we give two ways. Use any of them. We recommend using the second method, as it is more accurate.
Personal ID is highlighted here
Find out the type of key using ‘_readme.txt’ file
- Open the ransom demand message (‘_readme.txt’ file).
- Scroll down to the end of the file.
- There you will see a line with the text ‘Your personal ID’.
- Below is a line of characters that starts with ‘0334’ – this is your personal id.
Find out the type of key using ‘PersonalID.txt’ file
- Open disk C.
- Open directory ‘SystemID’.
- Open file named ‘PersonalID.txt’. This file lists ‘Personal ID’s that match the keys that the virus used to encrypt files.
The ‘Personal ID’ is not a key, it is an identifier related to a key that 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’, Koom virus used an online key. If you could not figure out how to determine which key was used to encrypt files, then we can help. Just write a request here or in the comments below.
Koom File Decrypt Tool : “No key for New Variant online ID”
If, when you try to decrypt .koom files, Koom File Decrypt Tool reports:
No key for New Variant online ID: *
Notice: this ID appears to be an online ID, decryption is impossible
It means that your files are encrypted with an ‘online key’ and their decryption is impossible, since only the vari authors have the key necessary for decryption. In this case, you need to use alternative methods listed below to restore the contents of encrypted files.
Koom File Decrypt Tool : “No key for New Variant offline ID”
If, during decryption of .koom files, Koom File Decrypt Tool reports:
No key for New Variant offline ID: *t1
Notice: this ID appears be an offline ID, decryption MAY be possible in the future.
It means the following: your files are encrypted with an ‘offline key’, but the key itself has not yet been obtained 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.
If for some reason you were unable to decrypt the encrypted files, then We recommend to follow the news on our Facebook or YouTube channels. So you ‘ll know right away that it ‘s possible to decrypt .koom files.
This video step-by-step guide will demonstrate How to remove Koom virus, Decrypt/Recover .koom files.
How to restore .koom files
As we already said, the Koom File Decrypt Tool can only decrypt files encrypted using the so called ‘offline key’. What to do when files were encrypted with an online key? Even in this case, everyone has a chance to recover the contents of encrypted files. This is possible due to the existence of several alternative ways to restore files. Each of these methods does not require a decryptor and a unique key, which is in the hands of criminals. The only thing we strongly recommend that you perform (if you have not already done so) is to perform a full scan of the computer. You must be 100% sure that Koom ransomware has been removed. To find and remove ransomware, use the free malware removal tools.
Recover .koom files with ShadowExplorer
The Windows OS (10, 8, 7 , Vista) has one very useful feature, it makes copies of all files that have been modified or deleted. This is done so that the user can recover, if necessary, the previous version of accidentally deleted or damaged files. These copies of the files are called ‘Shadow copies’. One tool that can help you recover files from the Shadow copies is ShadowExplorer. It is very small tool and easy to use. Unfortunately, ransomware often delete Shadow copies, thus blocking this method of recovering encrypted files. Nevertheless, be sure to try this method.
Visit the following page to download the latest version of ShadowExplorer for MS Windows. Save it on your Microsoft Windows desktop or in any other place.
438663 downloads
Author: ShadowExplorer.com
Category: Security tools
Update: September 15, 2019
After the downloading process is done, open a directory in which you saved it. Right click to ShadowExplorer-0.9-portable and select Extract all. Follow the prompts. Next please open the ShadowExplorerPortable folder as shown on the screen below.
Start the ShadowExplorer utility and then choose the disk (1) and the date (2) that you wish to recover the shadow copy of file(s) encrypted by the Koom virus as displayed on the image below.
Now navigate to the file or folder that you wish to recover. When ready right-click on it and click ‘Export’ button like below.
This video step-by-step guide will demonstrate How to recover encrypted files using Shadow Explorer.
Use PhotoRec to recover .koom files
Another alternative way to recover encrypted files is to use data recovery tools. We recommend using a program called PhotoRec. This tool is free and does not require installation. Below we will show in detail how to use it to restore encrypted files.
Download PhotoRec on your Windows Desktop by clicking on the following link.
When downloading is done, open a directory in which you saved it. Right click to testdisk-7.0.win and choose Extract all. Follow the prompts. Next please open the testdisk-7.0 folder as shown in the following example.
Double click on qphotorec_win to run PhotoRec for MS Windows. It’ll open a screen as displayed in the figure below.
Select a drive to recover as shown on the screen below.
You will see a list of available partitions. Select a partition that holds encrypted documents, photos and music as displayed on the screen below.
Click File Formats button and choose file types to recover. You can to enable or disable the restore of certain file types. When this is done, click OK button.
Next, click Browse button to choose where restored photos, documents and music should be written, then click Search. We strongly recommend that you save the recovered files to an external drive.
Count of recovered 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, click on Quit button. Next, open the directory where restored personal files are stored. You will see a contents like 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 restored files by extension and/or date/time.
This video step-by-step guide will demonstrate How to recover encrypted files using PhotoRec.
How to protect your PC from Koom ransomware
Most antivirus apps already have built-in protection system against the ransomware. Therefore, if your personal computer does not have an antivirus program, make sure you install it. As an extra protection, run the HitmanPro.Alert. All-in-all, HitmanPro.Alert is a fantastic tool to protect your computer from any ransomware. If ransomware is detected, then HitmanPro.Alert automatically neutralizes malware and restores the encrypted files. HitmanPro.Alert is compatible with all versions of MS Windows operating system from Windows XP to Windows 10.
Installing the HitmanPro Alert is simple. First you’ll need to download HitmanPro.Alert by clicking on the link below. Save it directly to your Microsoft Windows Desktop.
When the download is done, open the file location. You will see an icon like below.
Double click the HitmanPro Alert desktop icon. When the tool is launched, you will be displayed a window where you can choose a level of protection, as shown on the screen below.
Now press the Install button to activate the protection.
To sum up
This guide was created to help all victims of Koom ransomware virus. We tried to give answers to the following questions: how to remove ransomware; how to decrypt .koom files; how to recover encrypted files; 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 Koom ransomware related issues, go to here.
My recovered files are already corrupted. How do I go from here?
Which utility did you use to recover files?
Hi my laptop got koom ransomware virus. Can you please help me to get rid of virus and recover my data.
Use this instruction, it describes all possible ways to recover data
Buen día, necesito ayuda para recuperar mis archivos, están encriptados con clavé en línea, espero que pronto tengamos una solución, gracias
this guide lists all possible ways to recover files, try each one