Analysis by: Marcus Ma. Antonio Capistrano

ALIASES:

Ransom:Win32/FileCryptor (MICROSOFT), TR/FileCoder.gndyv (ANTIVIR), Win32/Filecoder.NJO trojan (NOD32)

 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: Downloaded from the Internet, 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 encrypts files with specific file extensions. It encrypts files found in specific folders.

  TECHNICAL DETAILS

File Size: 96,814 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 06 Feb 2018
Payload: Drops files, Deletes files, Displays windows

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 component file(s):

  • {malware file path}\8F185AD69BC908.key

It drops and executes the following files:

  • {malware file path}\8F185AD69BC908.cmd - is a batch file which searches for particular file extensions and launches 8F185AD69BC908.exe which performs encryption on the found files.
  • {malware file path}\8F185AD69BC908.exe - contains the encryption routine

Other System Modifications

This Ransomware deletes the following files:

  • {malware file path}\8F185AD69BC908.cmd
  • {malware file path}\8F185AD69BC908.exe
  • {malware file path}\8F185AD69BC908.key

Other Details

This Ransomware drops the following file(s)/component(s):

  • %Application Data%\{volume serial number}

(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 does the following:

  • If the malware is run on a Windows operating system version lower than Windows 2000, it displays the following message box and exits:
  • It executes the following commands:
    • ping -n 30 127.0.0.1
    • msg "%USERNAME%" "SPORA: LOCAL DECRYPTED"
    • 8F185AD69BC908.exe /key 8F185AD69BC908.key /file "%%~fd"
  • After it gathers files and the encryption routine is performed on those files, it displays the following windows:

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .docxml
  • .dot
  • .doc
  • .docx
  • .docm
  • .xls
  • .xlsx
  • .xlsm
  • .xlsb
  • .xltx
  • .xltm
  • .xlam
  • .odt
  • .rtf
  • .pdf
  • .bpdx
  • .msg
  • .email
  • .pptx
  • .pptm
  • .potx
  • .potm
  • .ppsx
  • .ppsm
  • .psd
  • .dwg
  • .cdr
  • .jpg
  • .jpeg
  • .tiff
  • .wmv
  • .mp4
  • .avi
  • .bmp
  • .cd
  • .1cd
  • .dbf
  • .sqlite
  • .dt
  • .cf
  • .cfu
  • .epf
  • .log
  • .lgf
  • .lgp
  • .elf
  • .cdn
  • .efd
  • .geo
  • .gsf
  • .zip
  • .rar
  • .7z
  • .backup
  • .tib
  • .bak
  • .bak1
  • .bak2
  • .bak3
  • .bak4
  • .002
  • .003
  • .004
  • .005
  • .006
  • .007
  • .008
  • .009
  • .010
  • .wbk
  • .ful
  • .wbcat
  • .backupdb
  • .pdb
  • .mdb
  • .accdb
  • .ace
  • .arj
  • .tar
  • .cab
  • .cfg
  • .dxf
  • .dwf
  • .vbox
  • .vdi
  • .vhd
  • .vhdx
  • .vmdk
  • .vmsd
  • .vmx
  • .vmxf
  • .vob
  • .pfx
  • .cer
  • .key
  • .lic
  • .sql
  • .sql1
  • .sql2
  • .db3
  • .dbs
  • .frm
  • .ldf
  • .sdb
  • .tmd
  • .sdf
  • .iso
  • .mdf
  • .mds
  • .bin
  • .nrg
  • .cue

It encrypts files found in the following folders:

  • {malware directory and its subdirectories}

NOTES:

Though it is able to gather files for encryption, it is not able to encrypt files due to some errors on its encryption routine.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.950.21
FIRST VSAPI PATTERN DATE: 06 Feb 2018
VSAPI OPR PATTERN File: 13.951.00
VSAPI OPR PATTERN Date: 07 Feb 2018

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.  
  • %Application Data%\{volume serial number}

Step 4

Scan your computer with your Trend Micro product to delete files detected as RANSOM_FILECRYPTOR.R046C0DB618. 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 the following Trend Micro Support pages for more information:

Step 5

Restore encrypted files from backup.


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