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RANSOM_KRYPTA.A

March 28, 2017
 Analysis by: Marvelous Pelin
 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size:

14,848 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

23 Mar 2017

Payload:

Displays windows, Encrypts 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 copies of itself into the affected system:

  • %Start Menu%\Programs\Startup\win32.exe

(Note: %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.)

Other Details

This Ransomware renames encrypted files using the following names:

  • {original filename and extension}.enc

It does the following:

  • This ransomware only encrypts files in the following folders:
    • %User Profile%\Documents
    • %User Profile%\Downloads
    • %User Profile%\Pictures
    • %User Profile%\Videos
    • %User Profile%\Desktop
    • %User Profile%\Music
    • {drive letter}:
  • It avoids encrypting files in the following path:
    • C:\
  • Once the "Entschlüsseln" button is clicked it will decrypt files under the %User Profile%\Music folder.

(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.)

NOTES:

This ransomware displays the following window after execution:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.296.02

FIRST VSAPI PATTERN DATE:

24 Mar 2017

VSAPI OPR PATTERN File:

13.297.00

VSAPI OPR PATTERN Date:

25 Mar 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

Restart in Safe Mode

[ Learn More ]

Step 4

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