Ransom.Win64.RYUK.YXBKC
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops files as ransom note. It avoids encrypting files with the following file extensions.
TECHNICAL DETAILS
Arrival Details
This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This Ransomware drops and executes the following files:
- C:\Windows\Temp\VVS.bat -> deletes shadowcopies
- cmd /c {Malware Path and Filename}.bat -> deletes self
It adds the following processes:
- C:\Windows\system32\rundll32.exe {Malware Path and Filename},Start
Other Details
This Ransomware does the following:
- Does NOT append any extension upon encryption.
- It needs to be executed as a service to proceed to its malicious routine.
- Encrypts removable, fixed, and remote drives
Ransomware Routine
This Ransomware avoids encrypting files with the following strings in their file name:
- README.TXT
- RECOVERY.BMP
- THUMBS.DB
- BOOT.INI
- NTUSER.INI
- BOOTSECT.BAK
- BOOTFONT.BIN
- AUTORUN.INF
- DESKTOP.INI
- NTUSER.DAT.LOG
- NTUSER.DAT
- NTLDR
- ICONCACHE.DB
It avoids encrypting files with the following strings in their file path:
- C\WINDOWS.OLD\
- C:\WINDOWS\
- C:\Program Files\
It drops the following file(s) as ransom note:
- {Encrypted Directory}\ReadMe.txt
- C:\Recovery.bmp
It avoids encrypting files with the following file extensions:
- RTP
- ICL
- THEME
- OCX
- ICNS
- LNK
- DLL
- NLS
- DRV
- EXE
- SCR
- CMD
- MSSTYLES
- HLP
- MSP
- ICS
- IDX
- NOMEDIA
- DIAGPKG
- ICO
- BIN
- DESKTHEMEPACK
- LOCK
- PRF
- LOCK
- DIAGCFG
- 386
- WPX
- MSC
- MSI
- SPL
- MPA
- MSU
- LDF
- CUR
- ROM
- SYS
- SHS
- THEMEPACK
- ADV
- DIAGCAB
- ANI
- COM
- CAB
- CPL
- MOD
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
-
Troj.Win32.TRX.XXPE50FFF050
Step 2
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 3
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 4
Identify and terminate files detected as Ransom.Win64.RYUK.YXBKC
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 5
Search and delete these files
- C:\Windows\Temp\VVS.bat
- {Malware Path and Filename}.bat
- {Encrypted Directory}\ReadMe.txt
- C:\Recovery.bmp
Step 6
Scan your computer with your Trend Micro product to delete files detected as Ransom.Win64.RYUK.YXBKC. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check the following Trend Micro Support pages for more information:
Step 7
Restore encrypted files from backup.
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