RANSOM_CRYONI.A

September 07, 2017
 Analysis by: Byron Jon Gelera
 Modified by: Rheniel Rhay Ramos
 ALIASES:

Trojan-Ransom.Win32.Onion.if (Kaspersky); Gen:Variant.Zusy.243093 (Bitdefender)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This Ransomware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

It encrypts files found in specific folders. It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

196,096 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

21 Jun 2017

Payload:

Encrypts files, Drops files

Arrival Details

This Ransomware 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 Ransomware drops the following files:

  • %User Temp%\qfjgmfgmkj.tmp

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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 drops and executes the following files:

  • %User Temp%\hjkhkHUhhjp.bat -> used to delete itself and the malware

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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 adds the following processes:

  • vssadmin.exe Delete Shadows /Quiet /All -> deletes shadow copies

Other Details

This Ransomware deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

  • All Drives
  • %Desktop%

(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.)

It avoids encrypting files with the following strings in their file path:

  • windows
  • Microsoft
  • Microsoft Help
  • Windows App Certification Kit
  • Windows Defender
  • ESET
  • COMODO
  • Windows NT
  • Windows Kits
  • Windows Mail
  • Windows Media Player
  • Windows Multimedia Platform
  • Windows Phone Kits
  • Windows Phone Silverlight Kits
  • Windows Photo Viewer
  • Windows Portable Devices
  • Windows Sidebar
  • WindowsPowerShell
  • Temp
  • NVIDIA Corporation
  • Microsoft.NET
  • Internet Explorer
  • Kaspersky Lab
  • McAfee
  • Avira
  • spytech software
  • sysconfig
  • Avast
  • Dr.Web
  • Symantec
  • Symantec_Client_Security
  • system volume information
  • AVG
  • Microsoft Shared
  • Common Files
  • Outlook Express
  • Movie Maker
  • Chrome
  • Mozilla Firefox
  • Opera
  • YandexBrowser
  • ntldr
  • wsus
  • Wsus

It avoids encrypting files found in the following folders:

  • A:\

It appends the following extension to the file name of the encrypted files:

  • .oni

It drops the following file(s) as ransom note:

  • {Folder containing encrypted files}\!!!README.html

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.484.03

FIRST VSAPI PATTERN DATE:

21 Jun 2017

VSAPI OPR PATTERN File:

13.485.00

VSAPI OPR PATTERN Date:

22 Jun 2017

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

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.
  • %User Temp%\hjkhkHUhhjp.bat
  • %User Temp%\qfjgmfgmkj.tmp
  • {Folder containing encrypted files}\!!!README.html

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYONI.A. 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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