How to Remove Combo13 Ransomware

This post focuses on the notorious ransomware called Combo13. Also included are Removal Steps, potential Recovery of Files that were encrypted by the virus, Computer Protection, as well as Tutorial Video.

Combo13 ransomware is a crypto-virus that intends to deny computer users to their own files by encrypting them with a complex algorithm method. The objective of the ransomware makers is to swindle money from victims by demanding ransom payment in exchange for Combo13 decryption tool and key.

Like most ransomware attack, Combo13 infiltrates the computer through hacking of the remote desktop protocol (RDP), mass mailing campaign, cracked software, serial key generators, fake software update, and drive-by-download techniques.

The moment Combo13 ransomware enters the computer, it explore the hard drive and look for common files like .doc, .xls, .ppt, .jpg, .mov, .pdf, .zip, .html, .dwg, .psd, and so on. Then, the virus encrypts those using AES + RSA technique and subsequently appends a .encrypted file extension. So, the normal write.doc files will turn into write.id-2F821A2F.[xmmh@tutanota.com].combo13 after the encryption process.  Attackers are demanding Bitcoin payment for the decryption tool that supposedly can restore all .encrypted files to their original format. To notify victims, Combo13 drops a FILES ENCRYPTED.TXT ransom note, which was actually patterned from that of other ransomware. Here is an excerpt.

All your files have been encrypted!
All your files have been encrypted due to a security problem with your PC. If you want to restore them, write us to the e-mail supportdata@cock.li
Write this ID in the title of your message (Unique ID)
In case of no answer in 24 hours write us to these e-mails:xmmh@tutanota.com
You have to pay for decryption in Bitcoins. The price depends on how fast you write to us. After payment we will send you the decryption tool that will decrypt all your files.
Free decryption as guarantee
Before paying you can send us up to 1 file for free decryption. The total size of files must be less than 1Mb (non archived), and files should not contain valuable information. (databases, backups, large excel sheets, etc.)
How to obtain Bitcoins
The easiest way to buy bitcoins is LocalBitcoins site. You have to register, click ‘Buy bitcoins’, and select the seller by payment method and price.
Also you can find other places to buy Bitcoins and beginners guide here:
How Can I Buy Bitcoin?
Attention!
Do not rename encrypted files.
Do not try to decrypt your data using third party software, it may cause permanent data loss.
Decryption of your files with the help of third parties may cause increased price (they add their fee to our) or you can become a victim of a scam.

Screenshot of Combo13

In order to avoid ransomware like Combo13, you should equipped the computer with a reliable anti-virus or anti-malware program. Also, avoid downloading executable files from distrusted sources whether it is freeware, software update, tools, or any program that are low in reputation. Same things goes with emails. Never open suspicious attachment especially if the sender is unknown…

Technical Details
Threat Name:Combo13 Ransomware, HiddenTear
Threat Type:Crypto-virus, File Locker, Encryption Virus
File Extension:.combo13
Ransomware Note File:FILES ENCRYPTED.TXT
Attacker’s emailxmmh@tutanota.co
supportdata@cock.li
Discovered by:@Amigo-A
Virus Alias:BitDefender : Gen:Heur.Ransom.HiddenTears.1
ESET-NOD32 : MSIL/Filecoder.AHV
Malwarebytes : Ransom.HiddenTear
Microsoft : Ransom:Win32/Higuniel.A
TrendMicro : TROJ_GEN.R002H09DG21

Backup your files

One important step before proceeding with the procedures below is to backup your files. Ransomware are not the same. Each has its unique sets of payloads aside from encrypting the files with complex method. Others tend to delete the infected files after certain period, while others keep them concealed on hidden places. In addition, ransomware decryption tools are not guaranteed to be perfect, there are instances that files suffer from damages during the decryption process.

So, create a backup copy of your entire Combo13 encrypted files right now.

Combo13 Ransomware Removal Guide

First thing to do is remove the Combo13 virus before attempting the decryption. Remember that as long as the ransomware is active, it will repeatedly encrypt the files on the compromised computer.

Infection of Combo13 ransom virus is dangerous to the system because it can inject files that runs each time Windows starts. To prevent the malicious files from loading, Windows operating system must run with minimal process and it can be done through SafeMode With Networking.

Stage 1 : Temporarily Disable System Restore on Windows OS

Because Combo13 and relevant virus is capable of reinstating itself by exploiting the System Restore of Windows, we suggests that you temporary disable System Restore while executing the steps. This option is also helpful to effectively run a full scan on the computer.

Do not forget to enable back System Restore after completing the removal of Combo13 ransomware. This feature is vital in reinstating the operating system to previous normal working condition in case of problems or conflicts occurs.

Stage 2 : Start Windows in Safe Mode With Networking

Windows 10 Guide

1. Click on Windows logo and select Power icon when options pop-ups.
2. Select Restart from the options while pressing Shift key on the keyboard.
3. Choose an Option window will appear, select the Troubleshoot button.
4. On next window, please choose Advanced Option.
5. On Advanced Option window, click on Startup Settings and then, click Restart button to reboot the computer.
6. When Windows boot on Startup Settings, press function key F5 or number 5 on keyboard.

A simpler alternative for Windows 10 users is to scan the computer with Microsoft Defender Offline. This will run a virus scan in the recovery environment.

Windows 8 Guide

1. Click Windows Start icon at the lower left section of the screen.
2. Open Search window and type Advanced in the field. It will open General PC Settings.
3. Click on Advanced Startup and then, click on Restart Now button.
4. Once the computer starts in Advanced Startup option menu, select Troubleshoot.
5. Next, click on Advanced Options to reveal the next section.
6. Click Startup settings and then, click Restart button to boot the PC in Startup Settings.
7. Use function key F5 or number key 5 to Enable Safe Mode with Networking.

Stage 3 : Scan the Computer with Sophos Antivirus

Ransomware files are placed deeply into the system and on various locations, thus, thorough scanning is vital to totally remove Combo13 virus. Aside from our suggested tool, you may also run your own security program.

To remove Combo13 automatically, scanning the computer with this efficient anti-malware tool is suggested. This scanner does not just uncover known threats like viruses or malware, it is also effective in discovering hazardous ransomware like Combo13.

1. Download Sophos Virus Removal Tool from the link below. Save the file on your computer where you can easily access it.

2. Once the download completes, browse the location of the file. Double-click to run the program and begin the install process.

Screnshot of Sophos Installer

3. On first windows of installation wizard, click Next to continue. Then, it will display the program’s License Agreement. You need to Accept the terms in order to proceed. If Windows prompts for User Account Control, please click Yes to proceed.

Screenshot of Sophos EULA Page

4. On succeeding windows, click Next or Continue to carry on with the installation. After completing the installation process, Launch Sophos Virus Removal Tool.

5. Internet connection is required when running this virus scanner in order to download important updates. Make sure that everything is up-to-date to effectively remove Combo13 ransomware and other relevant viruses.

6. Click the Start Scanning button to inspect the computer. This will check the system for presence of malicious objects, malware, and viruses. The tool reveals items that were found linked to Combo13 and other suspicious entities. Be sure to remove all identified threats.

Screenshot of Sophos Virus Scan

The above procedures should have totally eliminated Combo13 ransomware. However, if you found that there are still remnants of the virus, please proceed to succeeding procedures below.

Stage 4 : Double-check with Microsoft's Malicious Software Removal Tool

1. Download the free scanner called Malicious Software Removal Tool.

Download MSRT

2. The tool automatically checks the operating system and suggest appropriate download version. Click on Download button to begin. Save the file to a convenient location, preferably on Desktop.

3. After downloading the file, Windows will prompt that download has completed. Click Run to start scanning for Combo13 ransomware. Another option is to browse the location folder and double click on the file to run.

MSRT Icon

4. The tool will display Welcome screen, click Next. Please note the message "This tool is not a replacement for an antivirus product." You must understand that this program is made specifically to find and remove malware, viruses, Trojans, and other harmful elements on the computer. It was not designed to protect the computer.

MSRT Welcome

5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Combo13 ransom virus entities and other harmful files left on the computer will be found and removed. For advanced computer user, you can opt for Customized Scan, if there are other drives or folders you wanted to include in this scan.

MSRT Scan

6. Full scan may take a while, please wait for Malicious Software Removal Tool to complete the tasks. However, you may cancel the scan anytime by clicking on the Cancel button.

MSRT Scan

7. After scanning, the tool will reveal all identified threats. There may be other threats that our first scan fails to detect. Please remove/delete all detected items.

8. When removal procedure is complete, you may now close Malicious Software Removal Tool. We hope that Combo13 ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.

Recover Files from Combo13 Ransomware Infection

On this section, we will provide ways to decrypt files infected with Combo13 ransomware. Aside from dedicated decryption software and common tools, other options for file recovery are provided. As much as we can, we will update this area whenever there is new and more suitable decryption tool was made available.

Decrypting Combo13 infected files with Emsisoft Tools

This service from Emsisoft is helpful in unlocking encrypted files without paying the ransom. It gives three ways to detect the ransomware and provide suitable recovery method:

Upload ransom note – This is usually the .txt or .hta files that was generated by Combo13 ransomware.

Upload the encrypted file – The actual encrypted file. Choose the one that is less than 8MB in size.

Contact information – Enter the email address or any links provided as it appears in the ransom note of Combo13 virus.

Emsisoft Tools

After submitting any of the appropriate data, Emsisoft will attempt to identify the ransomware and provide keys if there are available.

Option 1: Windows Previous Version Tool

Windows Vista and Windows 7 have a feature called Previous Versions. However, this tool is only usable if restore point was made prior to ransomware infection. To use this tool as "recovery option" for files encypted by Combo13 virus, please follow these steps:

1. Open My Computer or Windows Explorer.

2. Right-click on the affected files or folders. From the drop-down list, please click on Restore previous versions.

3. New window will open display all backup copy of files and folders you wanted to recover. Choose the appropriate file and click on Open, Copy, or Restore. Restoring selected files overwrites the current locked files on the computer. The tool is not actually recovering files encrypted by Combo13. Instead, it restores files from backup copy.

Option 2: Use ShadowExplorer to restore files encrypted by Combo13 Ransomware

Just like Previous Version tool, ShadowExplorer is taking advantage of shadow copy created by Windows. This tool allows you to retrieve older version of files before it was encrypted by Combo13 ransomware.

1. Download ShadowExplorer from the official web site.

2. Install the program with the default settings.

3. The program should run automatically after installation. If not, double-click on ShadowExplorer icon.

4. You can see the drop-down list on top of the console. Please select proper drive and the most recent point-in-time shadow copies of files you wish to restore prior to Combo13 ransomware infection.

shadow3

5. Right-click on the Drive, Folder, or File you wish to restore and click Export...

6. Lastly, ShadowExplorer will prompt for location where you want to save the copy of recovered files.

How to protect the computer from Combo13 ransomware?

After the removal of the ransomware, it is important to prevent similar incident from happening again. In order to protect the computer effectively, computer user must know how Combo13 ransomware was able to infect the computer. To minimize the possible infection, staying away from the common sources of this virus is crucial.

How Combo13 ransomware can infect your computer?

The method of infecting the computers was found to be similar as other common viruses. Though, ransomware like Combo13 is seen to have efficient deployment via spam email messages, web injectors, malicious software installers, misleading online advertisements, and through another virus infection.

Once the virus is executed, it immediately infects the system. Then, Combo13 ransomware communicates to remote server so that unique key can be generated for the specific computer. After acquiring the key, it starts to decrypt target files using a complex method that is almost unbreakable. On the last stage of the attack, Combo13 ransomware demands for ransom money as payment for the decryption tool. To further understand the attack scheme, we have included an infographic below.

Infographic image of ransomware attack stages
You can print, download, or share the infographic by clicking the image.

Securing the computer against ransomware attack

Do a Regular File Back-up - Always backup your data on a separate storage devices such as external hard drives, optical discs, or online backup services.

Keep Your Software Updated - Make sure that you have the latest software updates especially on the operating system. Recent updates often contain vital security patches to help protect the computer against all forms of threats.

Install a Security Program - Protect the computer with effective anti-virus application using efficient real-time scanning. Regularly run a complete scan to check the computer for presence of malware.

Protect your files with Controlled Folder Access (Windows 10)

For Windows 10 users, aside from protecting the computer using anti-virus or anti-malware programs, one way to protect against ransomware attack is by using Controlled Folder Access. This feature of Windows Defender Security Center may not prevent the Combo13 ransomware infection, but it can protect the folder and files in general. Follow the steps to enable Controlled Folder Access in Windows 10.

1. Go to Windows 10 Taskbar and search for Windows Defender Security Center.

2. Open Windows Defender Security Center and click on Virus & Threat Protection icon.

Virus and Threat Protection

3. On next window, please click on Ransomware Protection.

4. Under Controlled Folder Access section, switch the slider to On. That will enable the feature and protect the folder against Combo13 or any type of ransomware.

Controlled Folder Access

5. Click on Protected Folderslink to include additional folders. Make sure that folders where important files are located should be included in the list.

Add Protected Folder

Troubleshooting Guide

Certain programs maybe blocked by Controlled Folder Access feature. To fix the issue, simply have the specific program to be white listed.

1. Under Protected Folders, click Allow an app through controlled folder access.

2. Next, click the Add an allowed app and include the target executable file.

This Controlled Folder Access feature is one way to protect files against Combo13. Other important things to do in keeping files safe against ransomware is through early prevention like keeping programs updated, install an efficient security program, an do regular file backup on a separate media drive.

Tutorial video to remove Combo13

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