RANSOM_GANDCRAB.THDCOAH

This Ransomware steals certain information from the system and/or the user.

It connects to certain websites to send and receive information. It deletes itself after execution.

It encrypts files found in specific folders.

Installation

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

• %Application Data%\Microsoft\{Random Characters}.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 adds the following mutexes to ensure that only one of its copies runs at any one time:

• Global\pc_group={Machine Workgroup}&ransom_id={16 hex values generated by the malware}

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
{Random Characters} = %Application Data%\Microsoft\{Random Characters}.exe

Information Theft

This Ransomware steals the following information:

• Machine Workgroup
• Anti Virus Software
• System Language
• Public IP Address
• Username
• Machine Name
• Machine Keyboard Layout
• OS Version and Platform
• Drive letters of drives, type, capacity, and free space

Stolen Information

This Ransomware sends the gathered information via HTTP POST to the following URL:

• http://{BLOCKED}r.bit/{"action"=result&e_"files"=%d&e_"size"=%I64u&e_"time"="time executed"}

Other Details

This Ransomware connects to the following URL(s) to get the affected system's IP address:

• Ipv4bot.whatismyipaddress.com

It connects to the following website to send and receive information:

• http://{BLOCKED}der.bit/
• http://{BLOCKED}ware.bit/

It does the following:

• It checks for the presence of the following antivirus and security applications:
  • AVP.EXE
  • ekrn.exe
  • avgnt.exe
  • ashDisp.exe
  • NortonAntiBot.exe
  • Mcshield.exe
  • avengine.exe
  • cmdagent.exe
  • smc.exe
  • persfw.exe
  • pccpfw.exe
  • fsguiexe.exe
  • cfp.exe
  • msmpeng.exe
• The malware does not proceed to its encryption routine if it detects a Russian keyboard layout and if it fails to communicate with the server
• This malware restarts the system using the following command:
  • shutdown -r -t 60 -f
• It changes the wallpaper of the victim after restarting the system.
  • 
    
• It avoids encrypting files found in the following folders:
  • ProgramData
  • IETldCache
  • Boot
  • Program Files
  • Tor Browser
  • Ransomware
  • All Users
  • Local Settings
  • Windows
  • Local AppData
• It avoids encrypting the following files:
  • desktop.ini
  • autorun.inf
  • ntuser.dat
  • iconcache.db
  • bootsect.bak
  • boot.ini
  • ntuser.dat.log
  • Thumbs.db
  • CRAB-DECRYPT.txt
• It encrypts all files except files with the following extensions:
  • .ani
  • .cab
  • .cpl
  • .cur
  • .diagcab
  • .diagpkg
  • .dll
  • .drv
  • .hlp
  • .ldf
  • .icl
  • .icns
  • .ico
  • .ics
  • .lnk
  • .key
  • .idx
  • .mod
  • .mpa
  • .msc
  • .msp
  • .msstyles
  • .msu
  • .nomedia
  • .ocx
  • .prf
  • .rom
  • .rtp
  • .scr
  • .shs
  • .spl
  • .sys
  • .theme
  • .themepack
  • .exe
  • .bat
  • .cmd
  • .CRAB
  • .crab
  • .GDCB
  • .gdcb
  • .gandcrab
  • .yassine_lemmou
• It deletes shadow copies by executing the following command:
  • cmd.exe /C WMIC.exe shadowcopy delete
• It executes the following commands to pop up the ransom note of the malware on Internet Explorer after restarting by executing the following commands:
  • iexplore.exe /C iexplore.exe SCODEF:3124 CREDAT:14337
  • iexplore.exe /C ie4uinit.exe -ShowQLIcon
• It disables the access of Internet Explorer homepage by executing the following commands:
  • {Malware File Name}.exe /C iexplore.exe -nohome

It performs DNS requests to the following sites:

• {BLOCKED}.{BLOCKED}servers.ru
• {BLOCKED}.{BLOCKED}.238.18
• {BLOCKED}.{BLOCKED}.214.39
• {BLOCKED}.{BLOCKED}.225.249

It deletes itself after execution.

Ransomware Routine

This Ransomware encrypts files found in the following folders:

• It will check the drive type of all drives from A to Z and will only encrypt the ones with the following drive type:
  • Removable Drives
  • Fixed Drives
  • Network Drives
  • Ramdisk Drives

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

• .CRAB

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

• {Encrypted Directory}\CRAB-DECRYPT.txt
  • 
    

NOTES: