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RANSOM_WALTRIX.SMLV

June 02, 2016
 Analysis by: Pearl Charlaine Espejo
 ALIASES:

Ransom:Win32/Exxroute!rfn (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size:

192,512 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

31 May 2016

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 files:

  • {malware path}\svchost.exe - copy of legitimate rundll32.exe
  • %User Startup%\{unique ID}{random character 1}.lnk
  • %User Startup%\{unique ID}{random character 2}.lnk
  • %All Users Profile%\Application Data\Z
  • %All Users Profile%\Application Data\{unique ID}.key
  • %All Users Profile%\Application Data\{unique ID}.html
  • %All Users Profile%\Application Data\{unique ID}.bmp
  • {folders containing encrypted files}\!Recovery_{unique ID}.html
  • {folders containing encrypted files}\!Recovery_{unique ID}.bmp
  • {folders containing encrypted files}\!Recovery_{unique ID}.txt
  • %Desktop%\!Recovery_{unique ID}.bmp
  • %Desktop%\!Recovery_{unique ID}.html
  • %Desktop%\!Recovery_{unique ID}.txt

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %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.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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 Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.187.64:443
  • {BLOCKED}.{BLOCKED}.82.19:443

It renames encrypted files using the following names:

  • {original filename.file extension}.crypt

It is capable of encrypting files in the affected system.

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.553.00

VSAPI OPR PATTERN Date:

27 May 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

Restart in Safe Mode

[ Learn More ]

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.
  • {malware path}\svchost.exe
  • %User Startup%\{unique ID}{random character 1}.lnk
  • %User Startup%\{unique ID}{random character 2}.lnk
  • %All Users Profile%\Application Data\Z
  • %All Users Profile%\Application Data\{unique ID}.key
  • %All Users Profile%\Application Data\{unique ID}.html
  • %All Users Profile%\Application Data\{unique ID}.bmp
  • %Desktop%\!Recovery_{unique ID}.bmp
  • %Desktop%\!Recovery_{unique ID}.html
  • %Desktop%\!Recovery_{unique ID}.txt
  • {folders containing encrypted files}\!Recovery_{unique ID}.html
  • {folders containing encrypted files}\!Recovery_{unique ID}.bmp
  • {folders containing encrypted files}\!Recovery_{unique ID}.txt

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_WALTRIX.SMLV. 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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