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RANSOM_SNEKUD.A

July 05, 2017
 Analysis by: Byron Jon Gelera
 ALIASES:

Ransom:Win32/LockCrypt.A!bit (Microsoft); Ransom.DXXD (Symantec)

 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


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 connects to certain websites to send and receive information.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size:

11,776 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

02 Jun 2017

Payload:

Connects to URLs/IPs, Drops files, 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.

Other System Modifications

This Ransomware adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
unlock = "c:\Windows\notepad.exe" c:\ReadMe.TxT

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Hacked = {victim ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
LegalNoticeCaption = "Dear owner, Your server hacked."

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
LegalNoticeText = "Decoding Files 1 Bitcoin, tomorrow 2 Bitcoin . NO money = NO decryption. More info in ReAdMe.TxT"

Other Details

This Ransomware connects to the following website to send and receive information:

  • {BLOCKED}.{BLOCKED}.17.222:21010

Ransomware Routine

This Ransomware avoids encrypting files with the following strings in their file name:

  • ReadMe.TxT

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

  • windows

It renames encrypted files using the following names:

  • {Random characters} ID {victim ID}.lock

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

  • {Path of Encrypted files}\ReadMe.TxT

It leaves text files that serve as ransom notes containing the following text:

NOTES:
It displays the following window during encryption:

By modifying the registry entries for the Legal Notice, It will display the following every time the user will log in:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.446.08

FIRST VSAPI PATTERN DATE:

02 Jun 2017

VSAPI OPR PATTERN File:

13.447.00

VSAPI OPR PATTERN Date:

03 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

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Hacked = {victim ID}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • LegalNoticeCaption = Dear owner, Your server hacked.
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • LegalNoticeText = Decoding Files 1 Bitcoin, tomorrow 2 Bitcoin . NO money = NO decryption. More info in ReAdMe.TxT
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • unlock = "c:\Windows\notepad.exe" c:\ReadMe.TxT

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.
  • {Path of encrypted files}\ReadMe.TxT

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_SNEKUD.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 6

Restore encrypted files from backup.


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