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RANSOM_LOCKY.DLDTATG

June 23, 2017
 Analysis by: Byron Jon Gelera
 ALIASES:

Win32/Filecoder.Locky.H (ESET-NOD32); Ransom:Win32/Locky.A (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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 employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.

It is capable of encrypting files in the affected system.

  TECHNICAL DETAILS

File Size:

274,274 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

21 Jun 2017

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:

  • (Folder of Encrypted Files}\loptr-{Random Hex Values}.htm -> Ransom Note

Autostart Technique

This Ransomware employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document
(Default) = "DrawDe Document"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document\DefaultIcon
(Default) = "{Malware Path and Filename},0"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document\shell\open\
command
(Default) = "{Malware Path and Filename} "%1""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document\shell\print\
command
(Default) = "{Malware Path and Filename} /p "%1""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document\shell\printto\
command
(Default) = "{Malware Path and Filename} /pt "%1" "%2" "%3" "%4""

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.kon
(Default) = "DrawDemo.Document"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.kon\ShellNew
NullFile = ""

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
DrawDemo.Document

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
.kon

Other Details

This Ransomware connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.140.170/checkupdate

It is capable of encrypting files in the affected system.

Ransomware Routine

This Ransomware renames encrypted files using the following names:

  • {first 8 characters of ID}--{next 4 characters of ID}--{last 4 characters of ID}--{8 hex characters}--{12 hex characters}.loptr

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.484.07

FIRST VSAPI PATTERN DATE:

21 Jun 2017

VSAPI OPR PATTERN File:

13.489.00

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

Delete this registry key

[ 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\Classes
    • .kon
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • DrawDemo.Document

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.  
  • (Folder of Encrypted Files}\loptr-{Random Hex Values}.htm

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_LOCKY.DLDTATG. 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.


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