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Ransom_FILEREKT.RY

August 11, 2017
 Analysis by: Ryan Paolo Maglaque
 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.

It deletes itself after execution.

It encrypts files with specific file extensions.

  TECHNICAL DETAILS

File Size:

17,920 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

31 Jul 2017

Payload:

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.

Installation

This Ransomware drops the following copies of itself into the affected system and executes them:

  • %Application Data%\REKT\FileRekt.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 the following files:

  • %Application Data%\REKT\public.key
  • %Application Data%\REKT\private.enc

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 creates the following folders:

  • %Application Data%\REKT

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
FileRekt = %Application Data%\REKT\FileRekt.exe

Other Details

This Ransomware deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .mid
  • .wma
  • .flv
  • .mkv
  • .mov
  • .avi
  • .asf
  • .mpeg
  • .vob
  • .mpg
  • .fla
  • .swf
  • .wav
  • .qcow2
  • .vdi
  • .vmdk
  • .vmx
  • .gpg
  • .aes
  • .ARC
  • .PAQ
  • .tar.bz2
  • .tbk
  • .bak
  • .tar
  • .tgz
  • .rar
  • .zip
  • .djv
  • .djvu
  • .svg
  • .bmp
  • .png
  • .gif
  • .raw
  • .cgm
  • .jpeg
  • .jpg
  • .tif
  • .tiff
  • .NEF
  • .psd
  • .cmd
  • .bat
  • .class
  • .jar
  • .java
  • .asp
  • .brd
  • .sch
  • .dch
  • .dip
  • .vbs
  • .asm
  • .pas
  • .cpp
  • .php
  • .ldf
  • .mdf
  • .ibd
  • .MYI
  • .MYD
  • .frm
  • .odb
  • .dbf
  • .mdb
  • .sql
  • .SQLITEDB
  • .SQLITE3
  • .asc
  • .lay6
  • .lay
  • .ms11 (Security copy)
  • .sldm
  • .sldx
  • .ppsm
  • .ppsx
  • .ppam
  • .docb
  • .mml
  • .sxm
  • .otg
  • .odg
  • .uop
  • .potx
  • .potm
  • .pptx
  • .pptm
  • .std
  • .pot
  • .pps
  • .sti
  • .sxi
  • .otp
  • .odp
  • .wks
  • .xltx
  • .xltm
  • .xlsx
  • .xlsm
  • .xlsb
  • .slk
  • .xlw
  • .xlt
  • .xlm
  • .xlc
  • .dif
  • .stc
  • .sxc
  • .ots
  • .ods
  • .hwp
  • .dotm
  • .dotx
  • .docm
  • .docx
  • .DOT
  • .max
  • .xml
  • .txt
  • .CSV
  • .uot
  • .RTF
  • .pdf
  • .XLS
  • .PPT
  • .stw
  • .sxw
  • .ott
  • .odt
  • .DOC
  • .pem
  • .csr
  • .crt
  • .key
  • wallet.dat

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

  • tmp
  • winnt
  • Application Data
  • AppData
  • Program Files(x86)
  • Program Files
  • temp
  • thumbs.db
  • $Recycle.Bin
  • System Volume Information
  • Boot
  • Windows

It renames encrypted files using the following names:

  • {Random values}

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

  • .REKT

NOTES:
This malware contains an error in encrypting files and might have code issues.

  SOLUTION

Minimum Scan Engine:

9.850

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

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • FileRekt = %Application Data%\REKT\FileRekt.exe

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\REKT

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom_FILEREKT.RY. 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 7

Restore encrypted files from backup.


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