RANSOM_GANDCRAB.THACOH

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 modifies the Internet Explorer Zone Settings.

It steals certain information from the system and/or the user.

It connects to certain websites to send and receive information. It is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It drops files as ransom note.

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:

• %Application Data%\Microsoft\{6 random character}.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={generated 16 hex values}

Autostart Technique

This Ransomware modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{11 random characters} = %Application Data%\Microsoft\{6 random character}.exe

Process Termination

This Ransomware terminates the following processes if found running in the affected system's memory:

• msftesql.exe
• sqlagent.exe
• sqlbrowser.exe
• sqlservr.exe
• sqlwriter.exe
• oracle.exe
• ocssd.exe
• dbsnmp.exe
• synctime.exe
• mydesktopqos.exe
• agntsvc.exeisqlplussvc.exe
• xfssvccon.exe
• mydesktopservice.exe
• ocautoupds.exe
• agntsvc.exeagntsvc.exe
• agntsvc.exeencsvc.exe
• firefoxconfig.exe
• tbirdconfig.exe
• ocomm.exe
• mysqld.exe
• mysqld-nt.exe
• mysqld-opt.exe
• dbeng50.exe
• sqbcoreservice.exe
• excel.exe
• infopath.exe
• msaccess.exe
• mspub.exe
• onenote.exe
• outlook.exe
• powerpnt.exe
• steam.exe
• sqlservr.exe
• thebat.exe
• thebat64.exe
• thunderbird.exe
• visio.exe
• winword.exe
• wordpad.exe

Web Browser Home Page and Search Page Modification

This Ransomware modifies the Internet Explorer Zone Settings.

Information Theft

This Ransomware steals the following information:

• IP address
• Username
• Machine name
• Machine workgroup
• Anti Virus Software
• System language
• Machine keyboard type
• OS version
• Current Windows version
• Active Drive/s and its type

Stolen Information

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

• {IP Address of domain}/curl.php?token=1019

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:

• {BLOCKED}ransom.bit
• {BLOCKED}ngcomputer.bit
• {BLOCKED}ft.bit
• {BLOCKED}d32.bit
• {BLOCKED}ab.bit

It is capable of encrypting files in the affected system.

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

Ransomware Routine

This Ransomware encrypts files with the following extensions:

• .1cd
• .3dm
• .3ds
• .3fr
• .3g2
• .3gp
• .3pr
• .7z
• .7zip
• .aac
• .ab4
• .abd
• .acc
• .accdb
• .accde
• .accdr
• .accdt
• .ach
• .acr
• .act
• .adb
• .adp
• .ads
• .agdl
• .ai
• .aiff
• .ait
• .al
• .aoi
• .apj
• .apk
• .arw
• .ascx
• .asf
• .asm
• .asp
• .aspx
• .asset
• .asx
• .atb
• .avi
• .awg
• .back
• .backup
• .backupdb
• .bak
• .bank
• .bay
• .bdb
• .bgt
• .bik
• .bin
• .bkp
• .blend
• .bmp
• .bpw
• .bsa
• .c
• .cash
• .cdb
• .cdf
• .cdr5
• .cdr6
• .cdr4
• .cdr5
• .cdr6
• .cdrw
• . cdx
• .ce1
• .ce2
• .cer
• .cfg
• .cfn
• .cgm
• .cf
• .class
• .cls
• .cmt
• .config
• .contact
• .cpi
• .cpp
• .cr2
• . craw
• .crt
• .crw
• .cry
• .cs
• .css
• .csv
• .d3dbsp
• .dac
• .das
• .dat
• .db
• .db_journal
• .db3
• .dbf
• .dbx
• .dc2
• .dcr
• .dcs
• .ddd
• .ddoc
• .ddrw
• .dds
• .def
• .der
• .des
• .design
• .dgc
• .dgn
• .dit
• .djvu
• .dng
• .doc
• .docm
• .docx
• .dot
• .dotm
• .dotx
• .drf
• .drw
• .dtd
• .dwg
• .dxb
• .dxf
• .dxg
• .edb
• .eml
• .eps
• .erbsql
• .erf
• .exf
• .fdb
• .ffd
• .fff
• .fh
• .fhd
• .fla
• .flac
• .flb
• .flf
• .flv
• .flvv
• .forge
• .fpx
• .fxg
• .gbr
• .gho
• .gif
• .gray
• .grey
• .groups
• .gry
• .h
• .hbk
• .hdd
• .hpp
• .html
• .ibank
• .ibd
• .ibz
• .idx
• .iif
• .iq
• .incpas
• .indd
• .info
• .info_
• .ini
• .iwi
• .jar
• .java
• .jnt
• .jpe
• .jpeg
• .jpg
• .js
• .json
• .k2p
• .kc2
• .kdbx
• .kdc
• .key
• .kpdx
• .kwm
• .laccdb
• .lbf
• .lck
• .ldf
• .lit
• .litemod
• .litesql
• .lock
• .log
• .ltx
• .lua
• .m
• .m2ts
• .m3u
• .m4ts
• .m4p
• .m4v
• .ma
• .mab
• .mapimail
• .max
• .mbx
• .md
• .mdb
• .mdc
• .mdf
• .mef
• .mfw
• .mid
• .mkv
• .mlb
• .mmw
• .mny
• .money
• .moneywell
• .mos
• .mov
• .mp3
• .mp4
• .mpeg
• .mpg
• .mrw
• .msf
• .msg
• .myd
• .nd
• .ndd
• .ndf
• .nef
• .nk2
• .nop
• .nrw
• .ns2
• .ns3
• .ns4
• .nsd
• .nsf
• .nsg
• .nsh
• .nvram
• .nwb
• .nx2
• .nxl
• .nyf
• .oab
• .obj
• .odb
• .odc
• .odf
• .odg
• .odm
• .odp
• .ods
• .odt
• .ogg
• .oil
• .omg
• .one
• .orf
• .ost
• .otg
• .oth
• .otp
• .ots
• .ott
• .p12
• .p7b
• .p7c
• .pab
• .pages
• .pas
• .pat
• .pbf
• .pcd
• .pct
• .pdb
• .pdd
• .pdf
• .pef
• .pem
• .pfx
• .php
• .pif
• .pl
• .plc
• .plus_muhd
• .pm!
• .pm
• .pmi
• .pmj
• .pml
• .pmm
• .pmo
• .pmr
• .pnc
• .pnd
• .png
• .pnx
• .pot
• .potm
• .potx
• .ppam
• .pps
• .ppsm
• .ppsx
• .ppt
• .pptm
• .pptx
• .prf
• .private
• .ps
• .psafe3
• .psd
• .pspimage
• .pst
• .ptx
• .pub
• .pwm
• .py
• .qba
• .qbb
• .qbm
• .qbr
• .qbw
• .qbx
• .qby
• .qcow
• .qcow2
• .qed
• .qtb
• .r3d
• .raf
• .rar
• .rat
• .raw
• .rdb
• .re4
• .rm
• .rtf
• .rvt
• .rw2
• .rwl
• . .sd
• .s3db
• .safe
• .sas7bdat
• .sav
• .save
• .say
• .sd0
• .sda
• .sdb
• .sdf
• .sh
• .sldm
• .sldx
• .slm
• .sql
• .sqlite
• .sqlite3
• .sqlitedb
• .sqlite-shm
• .sqlite-wal
• .sr2
• .srb
• .srf
• .srs
• .srt
• .srw
• .st4
• .st5
• .st6
• .st7
• .st8
• . stc
• .std
• .sti
• .stl
• .stm
• .stw
• .stx
• .svg
• .swf
• .sxc
• .sxd
• .sxg
• .sxi
• .sxm
• .sxw
• .tax
• .tbb
• .tbk
• .tbn
• .tex
• .tga
• .thm
• .tif
• .tiff
• .tlg
• .tlx
• .txt
• .upk
• .usr
• .vbox
• .vdi
• .vhd
• .vhdx
• .vmdk
• .vmsd
• .vmx
• .vmxf
• .vob
• .vpd
• .vsd
• .wab
• .wad
• .wallet
• .war
• .wav
• .wb2
• .wma
• .wmf
• .wmv
• .wpd
• .wps
• .x11
• .x3f
• .xis
• .xla
• .xlam
• .xlk
• .xlm
• .xlr
• .xls
• .xlsb
• .xlsm
• .xlsx
• .xlt
• .xltm
• .xltx
• .xlw
• .xml
• .xps
• .xxx
• .ycbcra
• .yuv
• .zip

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

• desktop.ini
• autorun.inf
• ntuser.dat
• iconcache.db
• bootsect.bak
• boot.ini
• ntuser.dat.log
• thumbs.db
• GDCB-DECRYPT.txt

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

• ProgramData
• Program Files
• Tor Browser
• Ransomware
• All Users
• Local Settings

It avoids encrypting files found in the following folders:

• %Application Data%\
• %Program Files%\
• %Program Files%\Common\
• %Windows%\

(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.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)

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

• .GDCB

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

• {Encrypted folder}\GDCB-DECRYPT.txt