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RANSOM_WALTRIX.B

April 27, 2016
 ALIASES:

Trojan:Win32/Dynamer!ac (Micorosft); a variant of Win32/Kryptik.EUSG (ESET); Trojan.Cryptolocker.AN (Symantec); Ransom.CryptXXX (Malwarebytes);

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet

This Trojan 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:

Varies

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

25 Apr 2016

Payload:

Encrypts files, Connects to URLs/IPs, Steals information

Arrival Details

This Trojan 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 Trojan drops the following non-malicious files:

  • %All Users Profile%\Application Data\{random file name}.dat

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
Pattern = ""

(Note: The default value data of the said registry entry is "{User Preference}".)

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = "0"

(Note: The default value data of the said registry entry is "{User Preference}".)

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%System Root%\Python{version}\tcl\tk{version}\demos\images\de_crypt_readme.bmp"

(Note: The default value data of the said registry entry is "{User Preference}".)

Other Details

This Trojan encrypts files with the following extensions:

  • .mp4
  • .psd
  • .mp3
  • .mid
  • .wma
  • .flv
  • .mkv
  • .mov
  • .avi
  • .asf
  • .mpeg
  • .vob
  • .mpg
  • .wmv
  • .fla
  • .swf
  • .wav
  • .qcow2
  • .vdi
  • .vmdk
  • .vmx
  • .gpg
  • .aes
  • .ARC
  • .PAQ
  • .tar
  • .bz2
  • .tbk
  • .bak
  • .tar
  • .tgz
  • .rar
  • .zip
  • .djv
  • .djvu
  • .svg
  • .bmp
  • .png
  • .gif
  • .raw
  • .cgm
  • .jpeg
  • .jpg
  • .tif
  • .tiff
  • .NEF
  • .cmd
  • .bat
  • .class
  • .jar
  • .java
  • .asp
  • .brd
  • .sch
  • .dch
  • .dip
  • .vbs
  • .asm
  • .pas
  • .cpp
  • .php
  • .ldf
  • .mdf
  • .ibd
  • .MYI
  • .MYD
  • .frm
  • .odb
  • .dbf
  • .mdb
  • .sql
  • .SQLITEDB
  • .SQLITE3
  • .asc
  • .lay6
  • .lay
  • .ms11
  • .sldx
  • .ppsm
  • .ppsx
  • .ppam
  • .docb
  • .mml
  • .sxm
  • .otg
  • .odg
  • .uop
  • .potx
  • .potm
  • .pptx
  • .pptm
  • .std
  • .sxd
  • .pot
  • .pps
  • .sti
  • .sxi
  • .otp
  • .odp
  • .wks
  • .xltx
  • .xltm
  • .xlsx
  • .xlsm
  • .xlsb
  • .slk
  • .xls
  • .doc
  • .xlw
  • .xlt
  • .xlm
  • .xlc
  • .dif
  • .stc
  • .sxc
  • .ots
  • .ods
  • .hwp
  • .dotm
  • .dotx
  • .docm
  • .docx
  • .DOT
  • .max
  • .xml
  • .txt
  • .CSV
  • .uot
  • .RTF
  • .pdf
  • .XLS
  • .PPT
  • .stw
  • .sxw
  • .ott
  • .odt
  • .DOC
  • .pem
  • .csr
  • .crt
  • .key
  • .eml
  • .dcu
  • .obj

It renames encrypted files using the following names:

  • {original file name}.crypt

It does the following:

  • It checks if it is being run in a virtual environment by querying the registry entry:
    HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString
  • It prevents to encrypt files containing any of the strings in its full pathname:
    • \Canon\
    • Roaming\Apple
    • Antivirus
    • plugscan
    • Microsoft
    • Windows
    • Google\Chrome
    • Plugins
    • Microsoft\Windows
    • winnt
    • Application Data
    • AppData
    • Program Files
    • temp
    • thumbs.db
    • Recycle Bin
    • System Volume Information
    • Boot
    • Windows

NOTES:

This malware drops the following files whenever it is able to encrypt files:

de_crypt_readme.txt

de_crypt_readme.html

de_crypt_readme.bmp

It steals the following information from the following programs:

  • BulletProof FTP
  • CuteFTP 6 Homec
  • CuteFTP 6 Professional
  • CuteFTP 7 Homec
  • CuteFTP 7 Professional
  • CuteFTP 8 Home
  • CuteFTP 8 Professional
  • Digsby
  • Far
  • Far2
  • FileZilla
  • FlashFXP 3
  • FlashFXP 4
  • FTP Explorer
  • FTPClient
  • FTPRush
  • FTPWare COREFTP
  • Google Talk
  • Internet Account Manager
  • Ipswitch WS_FTP
  • MySpace
  • Outlook
  • Outlook Express
  • Paltalk
  • Pidgin
  • Scribe
  • SmartFTP
  • SoftX.org FTPClient
  • Sota FFFTP
  • Total Commander
  • Trillian
  • TurboFTP
  • VanDyke
  • Windows Commander
  • Windows Live Mail

It also steals information from cookies, Google Chrome User Data, and Bitcoin wallet files containing the following in their file name:

  • WALLET
  • _WALLET
  • .WALLET

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.480.05

FIRST VSAPI PATTERN DATE:

21 Apr 2016

VSAPI OPR PATTERN File:

12.481.00

VSAPI OPR PATTERN Date:

22 Apr 2016

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 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

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: Pattern = ""
      To: Pattern = "{User Preference}"
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: TileWallpaper = "0"
      To: TileWallpaper = "{User Preference}"
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: Wallpaper = "%System Root%\Python{version}\tcl\tk{version}\demos\images\de_crypt_readme.bmp"
      To: Wallpaper = "{User Preference}"

Step 4

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.  
  • %All Users Profile%\Application Data\{random file name}.dat
  • de_crypt_readme.bmp
  • de_crypt_readme.html
  • de_crypt_readme.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_WALTRIX.B. 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 6

Restore encrypted files from backup.


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