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RANSOM_CRYPTEAR.SM

June 15, 2016
 Analysis by: Rhena Inocencio
 ALIASES:

Ransom:MSIL/Ryzerlo.A (Microsoft), a variant of MSIL/Filecoder.Z (ESET)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

This is the Trend Micro detection for files that exhibit certain behaviors.

  TECHNICAL DETAILS

File Size:

212,480 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 Apr 2016

Payload:

Encrypts files, Displays message/message boxes

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 copies of itself into the affected system:

  • %User Profile%\AppData\svchost.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It adds the following processes:

  • It executes the dropped copy %User Profile%\AppData\svchost.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Other System Modifications

This Trojan modifies the following file(s):

  • It encrypts files and appends the extension .locked

Other Details

This Trojan encrypts files with the following extensions:

  • .doc
  • .docx
  • .xls
  • .xlsx
  • .ppt
  • .pptx
  • .mp3
  • .jpg
  • .png
  • .hwp
  • .pdf
  • .exe

It drops the following file(s)/component(s):

  • %Desktop%\Your files are locked!!.txt - ransom note
  • {malware path}\adobe.txt - contains computer name and username
  • %User Profile%\winsys.txt

(Note: %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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

This is the Trend Micro detection for:

  • Variants of Hidden Tear ransomware

NOTES:

The dropped ransom note contains the following message:

  SOLUTION

Minimum Scan Engine:

9.800

VSAPI OPR PATTERN File:

12.453.00

VSAPI OPR PATTERN Date:

07 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

Identify and terminate files detected as RANSOM_CRYPTEAR.SM

[ Learn More ]
  1. 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.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete this file

[ 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}\adobe.txt
  • %User Profile%\winsys.txt
  • Your files are locked!!.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYPTEAR.SM . 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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