Modified by: Earle Maui Earnshaw
ALIASES:

Trojan:Win32/Occamy.C (Microsoft); Trojan-Ransom.FileCrypter (Ikarus)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

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.

  TECHNICAL DETAILS

File Size: 12,384,840 bytes
File Type: EXE
File Compression: UPX
Memory Resident: Yes
Initial Samples Received Date: 18 Mar 2019
Payload: Displays graphics/image, Plays a Chinese song, Modifies system registry

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 the following files:

  • %Windows%\{Random Characters}.bmp
  • %User Temp%\XiaoBa.mp3
  • %User Temp%\XiaoBa.bmp
  • %System Root%\autoexec.{Random Characters}[{BLOCKED}eng@yeah.net].XiaoBa

It adds the following processes:

  • vssadmin delete shadow /all /quiet -> deletes all shadow copies
  • wmic shadowcopy delete -> deletes all shadow copies
  • bcdedit /set {default} boostatuspolicy ignoreallfailures -> Disables Windows Recovery on Startup
  • bcdedit /set {default} recoveryenabled no -> Disables Windows Recovery on Startup
  • wbadmin delete catalog -quiet -> Clears Windows Server backup history

Other System Modifications

This Ransomware changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %Windows%\{Characters}.bmp

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Temp%\XiaoBa.bmp

It sets the system's desktop wallpaper to the following image:

Other Details

This Ransomware does the following:

  • Displays the following:
  • The window also plays a Chinese song.
  • Shows the message box if the input password is incorrect:
  • Displays the following:
  • Encrypts all files in all drives.
  • Deletes encrypted files if demands are not met.

Ransomware Routine

This Ransomware appends the following extension to the file name of the encrypted files:

  • {File Name}.{Random Characters}[{BLOCKED}eng@yeah.net].XiaoBa

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.878.05
FIRST VSAPI PATTERN DATE: 18 Mar 2019
VSAPI OPR PATTERN File: 14.879.00
VSAPI OPR PATTERN Date: 19 Mar 2019

Step 1

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 2

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 3

Restart in Safe Mode

[ Learn More ]

Step 4

Reset your Desktop properties

[ Learn More ]

Step 5

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.  
  • %Windows%\{Random Characters}.bmp
  • %User Temp%\XiaoBa.mp3
  • %User Temp%\XiaoBa.bmp
  • %System Root%\autoexec.{Random Characters}[{BLOCKED}eng@yeah.net].XiaoBa

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.XIAOBA.AA. 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 this Knowledge Base page for more information.

Step 7

Restore encrypted files from backup.


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