Remove Usam Ransomware (Decryption Method)

By Chona Esjay | Posted on June 16, 2020 |

According to malware researcher Michael Gillespie, there is a new variant of DJVU/STOP malware and it is called Usam ransomware. So far, this is the 233rd variant and this family of threat shows no sign of receding with the attack. Clearly, developers behind this STOP malware specifically Usam virus are generating money by selling their decryption tool to victims.

As ransomware, Usam starts the operation by searching the infected drive for common user’s files including docx, xlsx, pptx, .zip, pdf, jpg, png, pdf, dwg, html, and many more. Then, it will use a complex algorithm method to scramble its core data that will prevent computer users from opening it. Afterwards, Usam ransomware appends the infected object with .usam file extension. To site an example, a simple mypic.jpg will turn into mypic.jpg.usam after it was fully encrypted by the virus.

As usual, attackers will take this opportunity to swindle money from victims by asking them to send $980 if they wish to restore back all infected files to its previous format. This demand is fully documented on the ransom note file called _readme.txt, which states the following:

ATTENTION!
Don’t worry, you can return all your files!
All your files like photos, 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:
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.

As of this point, people behind Usam ransomware are certain that the entire .usam files are encrypted and only them have the ability to decrypt it. However, the Usam decryption tool they are offering is too expensive that not all victims can afford. Most importantly, dealing with online crooks is too risky. There is no assurance that both Usam decryption tool and private key will be transmitted to rightful person after paying the ransom demand.

Usam Virus

As suggested by computer security experts, it is much safer to have a backup copy of all Usam encrypted files and wait for the free official decryption tool from legitimate security vendors and malware researchers. For now, cleaning the computer and removing Usam ransomware is the best thing to do in order to prevent new files from getting infected.

How to Remove Usam Ransomware

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

Though affected files may be impossible to decrypt due to complexity of the encryption, you can still try recovery method like alternative tool, Shadow Explorer or Previous Version as described below.

Stage 1: Scan the Computer with Anti-Malware Tool

1. Download free anti-malware scanner called MalwareBytes Anti-Malware.
Malwarebytes Anti-Malware Download Link (this will open a new window)

2. After downloading, install the program. It may run automatically or you have to double-click on the downloaded file MBSetup.exe.

3. Carry out the installation with default setup process.

4. After the installation process, click the Get Started button to launch the program.

5. Continue with the prompts until the main program opens.

6. On the main console, click on Scan to run most complete detection method to find hidden objects associated to Usam ransomware.

7. Scanning may take a while. Please wait until the anti-malware tool is done with the checking.

MBAM-threatscan

8. Once the scan has completed, the tool will display the list of detected threats. Remove all identified malicious items and restart the computer if necessary.

Stage 2: Double-check for Usam’s leftover with Microsoft’s Malicious Software Removal Tool

1. Download the free scanner called Malicious Software Removal Tool.
Malicious Software Removal Tool Download Link (this will open a new window)

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 Usam 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.

msrt1

5. Next, you will see Scan Type. Please choose Full Scan to ensure that all Usam 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.

msrt2

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.

msrt3

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 Usam ransomware have been completely deleted from the computer. Please restart Windows to proceed with the normal operation.

Stage 3 : Unlocking files with Usam Decryption Tool

Emsisoft Decryptor for STOP Djvu will work only if affected files were encrypted using Offline Keys. Usam ransomware uses the alternate Offline Keys during encryption if there is a problem encountered while communicating to a remote command-and-control server. Follow the guide to start recovering .usam encrypted files.

1. As precautionary measures, we suggest to BACKUP all your .usam encrypted files first on a separate media (USB Drive, Flash Drive, DVD Discs, etc…).

2. Download Emsisoft Decryptor for STOP Djvu from this archive page.

3. Right-click on decrypt_STOPDjvu.exe and click “Run as Administrator“. Windows may prompt “Do you want to allow this app…” just click Yes to continue.

4. By default, the tool will pre-populate the locations where encrypted files were identified. To include other directories, simply click Add Folder button.

5. To start recovering files infected by Usam ransomware, click on Decrypt button to start the procedure. The interface will display status of the current decryption process.

decrypt_STOPDjvu.exe

We will update this section once the full decryption tool is on hand. In the meantime, please try other options below if the above procedure is not not effective.

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 Usam ransomware infection. To use this tool and recover files affected by the 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 encrypted files on the computer.

Option 2: Use ShadowExplorer to restore files encrypted by Usam 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 Usam 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 Usam 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.