Ransom_WALTRIX.SMQ

July 29, 2016
 Analysis by: Cris Nowell Pantanilla
 ALIASES:

Ransom:Win32/Exxroute.C (Microsoft), Trojan-Ransom.Win32.CryptXXX.bkq (Kaspersky)

 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, Dropped by other malware

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:

458,752 bytes

Memory Resident:

Yes

Initial Samples Received Date:

20 Jun 2016

Payload:

Modifies files

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:

  • %User Startup%\!{random}.lnk
  • {malware path}\explorer.exe
  • %Program Data%\!{random}.cfg
  • {path of encrypted file}\!{random}.txt
  • {path of encrypted file}\!{random}.html
  • %Start Menu%\!{random}.txt
  • %Start Menu%\!{random}.html
  • %Start Menu%\!{random}.bmp
  • {path of encrypted file}\!{random}.bmp

(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.. %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu 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.)

It injects threads into the following normal process(es):

  • explorer.exe

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.194.116:443

It renames encrypted files using the following names:

  • {original file name.file extension}.crypz

It is capable of encrypting files in the affected system.

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.603.00

VSAPI OPR PATTERN Date:

21 Jun 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

Restart in Safe Mode

[ Learn More ]

Step 3

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.
  • %User Startup%\!{random}.lnk
  • {malware path}\explorer.exe
  • %Program Data%\!{random}.cfg
  • {path of encrypted file}\!{random}.txt
  • {path of encrypted file}\!{random}.html
  • %Start Menu%\!{random}.txt
  • %Start Menu%\!{random}.html
  • %Start Menu%\!{random}.bmp
  • {path of encrypted file}\!{random}.bmp

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom_WALTRIX.SMQ. 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 5

Restore encrypted files from backup.


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