Analysis by: Rheniel Rhay Ramos

 ALIASES:

Ransom:Win32/DefrayCrypt.A (Microsoft); Ransom.Wannacry (Symantec); TR/Graftor.xgajj (Avira)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: Yes

  • 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 connects to certain websites to send and receive information.

It drops files as ransom note.

  TECHNICAL DETAILS

File Size: 1,245,184 bytes
Initial Samples Received Date: 26 Aug 2017
Payload: 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 files:

  • {drive}:\test.avg ← deleted right away

It drops and executes the following files:

  • %Temp%\{random name} ← a captured screenshot of the infected system

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 4024

Other Details

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

  • {BLOCKED}thetic-electr.{BLOCKED}hostapp.com
  • {BLOCKED}thetic-electr.{BLOCKED}hostapp.com/i.php

It encrypts files with the following extensions:

  • .001
  • .3ds
  • .7zip
  • .BESR
  • .BIN
  • .CDR
  • .DAA
  • .DMG
  • .DRW
  • .ISO
  • .ISZ
  • .MDF
  • .NRG
  • .PBF
  • .SQLITE
  • .SQLITE2
  • .SQLITE3
  • .SQLITEDB
  • .SVG
  • .UIF
  • .WMF
  • .abr
  • .accdb
  • .afi
  • .arw
  • .asm
  • .bkf
  • .c4d
  • .cab
  • .cbm
  • .cbu
  • .class
  • .cls
  • .cpp
  • .cr2
  • .crw
  • .csh
  • .csv
  • .dat
  • .dbx
  • .dcr
  • .dgn
  • .djvu
  • .dng
  • .doc
  • .docm
  • .docx
  • .dwfx
  • .dwg
  • .dxf
  • .fla
  • .fpx
  • .gdb
  • .gho
  • .ghs
  • .hdd
  • .html
  • .iso
  • .iv2i
  • .java
  • .key
  • .lcf
  • .matlab
  • .max
  • .mdb
  • .mdi
  • .mrbak
  • .mrimg
  • .mrw
  • .nef
  • .odg
  • .ofx
  • .orf
  • .ova
  • .ovf
  • .pbd
  • .pcd
  • .pdf
  • .php
  • .pps
  • .ppsx
  • .ppt
  • .pptx
  • .pqi
  • .prn
  • .psb
  • .psd
  • .pst
  • .ptx
  • .pvm
  • .pzl
  • .qfx
  • .qif
  • .r00
  • .raf
  • .rar
  • .raw
  • .reg
  • .rw2
  • .s3db
  • .skp
  • .spf
  • .spi
  • .sql
  • .sqlite-journal
  • .stl
  • .sup
  • .swift
  • .tib
  • .txf
  • .u3d
  • .v2i
  • .vcd
  • .vcf
  • .vdi
  • .vhd
  • .vmdk
  • .vmem
  • .vmwarevm
  • .vmx
  • .vsdx
  • .xls
  • .wallet
  • .win
  • .xlsm
  • .xlsx
  • .zip

It checks for the presence of the following antivirus and security applications:

  • kaspersky
  • eset
  • avast

Ransomware Routine

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

  • bootsect.bak
  • boot.ini
  • ntldr
  • ntdetect.com
  • ntuser.dat
  • windows

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

  • {folder containing encrypted files}\FILES.TXT
  • {malware path}\HELP.TXT

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

  • Don't panic, read this and contact someone from IT department. Your computer has been infected with a virus known as ransomware. All files including your personal or business documents, backups and projects are encrypted. Encryption is very sophisticated and without paying a ransom you won't get your files back. You could be advised not to pay, but you should anyway get in touch with us. Ransom value for your files is 5000$ to be paid in digital currency called Bitcoin. If you have questions, write us. If you have doubts, write us. If you want to negotiate, write us. If you want to make sure we can get your files back, write us. {BLOCKED}ov@protonmail.ch glushkov@tutanota.de igor.glushkov.83@mail.ru In case we don't respond to an email within one day, download application called BitMessage and reach to us for the fastest response. BitMessage BM-{BLOCKED}Fb5ZRaMuYdryqxsMNxFMudibvnY6 ######################################################################### To someone from IT department This is custom developed ransomware, decrypter won't be made by an antivirus company. This one doesn't even have a name. It uses AES-256 for encrypting files, RSA-2048 for storing encrypted AES-256 password and SHA-2 for keeping the encrypted file integrity. It's written in C++ and have passed many quality assurance tests. To prevent this next time use offline backups. #########################################################################

  SOLUTION

Minimum Scan Engine: 9.850
VSAPI OPR PATTERN File: 13.624.02
VSAPI OPR PATTERN Date: 26 Aug 2017
OPP PATTERN File: 13.625.00
OPP PATTERN Date: 27 Aug 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_DEFRAY.B. 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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