Analysis by: Byron Jon Gelera
ALIASES:

Ransom:MSIL/Ryzerlo.A (Microsoft); Trojan.Cryptolocker.Y (Symantec)

 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.

It gathers certain information on the affected computer.

  TECHNICAL DETAILS

File Size: 212,992 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 19 Aug 2016
Payload: Connects to URLs/IPs, Displays graphics/image, Downloads files, Encrypts 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.

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

  • http://i.imgur.com/{BLOCKED}.jpg

It saves the files it downloads using the following names:

  • %User Profile%\ransom.jpg - image used as wallpaper

Information Theft

This Trojan gathers the following information on the affected computer:

  • Machine Name
  • User Name

Other Details

This Trojan does the following:

  • It connects to the following website to send information:
    • http://www.{BLOCKED}m.hol.es/savekey.php
    • http://www.{BLOCKED}m.hol.es/createkeys.php
  • It encrypts files with the following extensions in the %Desktop%\test sub folders and appends .locked as the new file extension of the encrypted files:
    • .txt
    • .doc
    • .docx
    • .xls
    • .xlsx
    • .ppt
    • .pptx
    • .odt
    • .jpg
    • .png
    • .csv
    • .sql
    • .mdb
    • .sln
    • .php
    • .asp
    • .aspx
    • .html
    • .xml
    • .psd

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.482.04
FIRST VSAPI PATTERN DATE: 22 Apr 2016
VSAPI OPR PATTERN File: 12.483.00
VSAPI OPR PATTERN Date: 23 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.SMILA

[ 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 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 Profile%\ransom.jpg

Step 5

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