RANSOM_SIGMA.B

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

It connects to certain websites to send and receive information. It terminates itself if it detects it is being run in a virtual environment. It is capable of encrypting files in the affected system.

It encrypts files with specific file extensions. It encrypts files found in specific folders. 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 a copy of itself in the following folders using different file names:

• %Application Data%\Microsoft\{GUID 32 Hex Values}\taskwgr.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 file(s)/component(s):

• %Application Data%\tor\lock
• %Application Data%\tor\state.tmp
• %Application Data%\tor\unverified-microdesc-consensus.tmp
• %Application Data%\tor\cached-certs.tmp
• %Application Data%\tor\cached-microdesc-consensus.tmp
• %Application Data%\tor\cached-microdescs.new
• %Application Data%\tor\state.tmp
• %Application Data%\Microsoft\{GUID 32 Hex Values}\System.zip
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Data\Tor\geoip
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Data\Tor\geoip6
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libeay32.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libevent-2-0-5.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libevent_core-2-0-5.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libevent_extra-2-0-5.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libgcc_s_sjlj-1.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\libssp-0.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\ssleay32.dll
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\tor-gencert.exe
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\tor.exe
• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\zlib1.dll

(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 and executes the following files:

• %Application Data%\Microsoft\{GUID 32 Hex Values}\Tor\svchost.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 creates the following folders:

• %Application Data%\Microsoft\{GUID 32 Hex Values}

(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
chrome = Rundll32.exe SHELL32.DLL,ShellExec_RunDLL %Application Data%\Microsoft\{GUID 32 Hex Values}\taskwgr.exe

Other System Modifications

This Ransomware sets the system's desktop wallpaper to the following image:

Information Theft

This Ransomware steals the following information:

• Username
• OS
• Machine Name
• No. of Files Encrypted
• Country

Other Details

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

• http://{BLOCKED}qj7azyldq2.{BLOCKED}n/control.php

It terminates itself if it detects it is being run in a virtual environment.

It does the following:

• It executes this command if it detects it is being debugged or when run in virtual environment.
• - cmd.exe /C ping 1.1.1.1 -n 1 -w 3000 > Nul & Del "{Initial Malware Path}\{Malware Name}.exe"

It is capable of encrypting files in the affected system.

It checks if the following virtual machine or sandbox related module(s) is loaded in the affected system:

• VBoxHook.dll
• SbieDll.dll

It does not proceed to its malicious routine if it detects that it is being debugged.

Ransomware Routine

This Ransomware encrypts files with the following extensions:

• .iso
• .sln
• .suo
• .1cd
• .3d
• .3d4
• .3df8
• .3dm
• .3ds
• .3fr
• .3g2
• .3gp
• .3gp2
• .3mm
• .3pr
• .7z
• .7zip
• .aac
• .ab4
• .abk
• .abw
• .ac3
• .accdb
• .accde
• .accdr
• .accdt
• .ace
• .ach
• .acr
• .act
• .adb
• .ade
• .adi
• .adp
• .adpb
• .adr
• .ads
• .adt
• .agdl
• .ai
• .aiff
• .aim
• .aip
• .ais
• .ait
• .al
• .amf
• .amr
• .amu
• .amx
• .amxx
• .ans
• .aoi
• .ap
• .ape
• .api
• .apj
• .arc
• .ari
• .arj
• .aro
• .arr
• .arw
• .asa
• .asc
• .ascx
• .ase
• .asf
• .ashx
• .asm
• .asmx
• .asp
• .aspx
• .asr
• .asx
• .avi
• .avs
• .awg
• .back
• .backup
• .backupdb
• .bak
• .bank
• .bay
• .bck
• .bdb
• .bdp
• .bdr
• .bgt
• .bib
• .bic
• .big
• .bik
• .bin
• .bkf
• .bkp
• .blend
• .blp
• .bmc
• .bmf
• .bml
• .bmp
• .boc
• .bp2
• .bp3
• .bpl
• .bpw
• .bsp
• .c
• .cag
• .cam
• .cap
• .car
• .cbr
• .cbz
• .cc
• .ccd
• .cch
• .cd
• .cdf
• .cdr
• .cdr3
• .cdr4
• .cdr5
• .cdr6
• .cdrw
• .cdx
• .ce1
• .ce2
• .cer
• .cfg
• .cgf
• .cgm
• .chk
• .cib
• .class
• .clr
• .cls
• .cms
• .cmt
• .cod
• .col
• .config
• .contact
• .cp
• .cpi
• .cpp
• .cr2
• .craw
• .crd
• .crt
• .crw
• .cs
• .csh
• .csi
• .csl
• .cso
• .css
• .csv
• .ctt
• .cty
• .cwf
• .dac
• .dal
• .dap
• .dat
• .db
• .db3
• .db_journal
• .dbb
• .dbf
• .dbx
• .dc2
• .dcp
• .dcr
• .dcs
• .dcu
• .ddc
• .ddcx
• .ddd
• .ddoc
• .ddrw
• .dds
• .dem
• .der
• .des
• .design
• .dev
• .dex
• .dgc
• .dic
• .dif
• .dii
• .dir
• .disk
• .dit
• .divx
• .diz
• .djvu
• .dmg
• .dng
• .dob
• .doc
• .docm
• .docx
• .dot
• .dotm
• .dotx
• .dox
• .dpk
• .dpl
• .dpr
• .drf
• .drw
• .dsk
• .dsp
• .dtd
• .dvd
• .dvi
• .dvx
• .dwg
• .dxb
• .dxe
• .dxf
• .dxg
• .edb
• .elf
• .eml
• .eps
• .eql
• .erbsql
• .erf
• .err
• .euc
• .evo
• .ex
• .exf
• .exif
• .f90
• .faq
• .fcd
• .fdb
• .fdr
• .fds
• .ff
• .ffd
• .fff
• .fh
• .fhd
• .fla
• .flac
• .flf
• .flp
• .flv
• .flvv
• .for
• .fpp
• .fpx
• .fxg
• .gam
• .gif
• .gray
• .grey
• .grf
• .groups
• .gry
• .gthr
• .gz
• .gzig
• .h
• .h3m
• .h4r
• .hbk
• .hdd
• .hpp
• .htm
• .html
• .ibank
• .ibd
• .ibz
• .idx
• .iif
• .iiq
• .img
• .incpas
• .indd
• .ink
• .ipa
• .isu
• .isz
• .itdb
• .itl
• .iwd
• .jar
• .jav
• .java
• .jc
• .jfif
• .jgz
• .jif
• .jiff
• .jnt
• .jpc
• .jpe
• .jpeg
• .jpf
• .jpg
• .jpw
• .js
• .kc2
• .kdbx
• .kdc
• .key
• .kmz
• .kpdx
• .kwd
• .kwm
• .laccdb
• .lbi
• .lcd
• .lcf
• .ldb
• .ldf
• .lgp
• .lit
• .log
• .lp2
• .ltm
• .ltr
• .lua
• .lvl
• .m
• .m2ts
• .m3u
• .m4p
• .m4v
• .mag
• .man
• .map
• .mapimail
• .max
• .mbox
• .mbx
• .mcd
• .md
• .md3
• .mdb
• .mdc
• .mdf
• .mdl
• .mdn
• .mds
• .mef
• .mfw
• .mic
• .mid
• .mip
• .mkv
• .mlb
• .mlx
• .mmw
• .mny
• .mod
• .moneywell
• .mos
• .mov
• .moz
• .mp3
• .mp4
• .mpeg
• .mpg
• .mrw
• .msg
• .msp
• .mxp
• .myd
• .nav
• .ncd
• .nd
• .ndd
• .ndf
• .nds
• .nef
• .nfo
• .nk2
• .nop
• .now
• .nrg
• .nri
• .nrw
• .ns2
• .ns3
• .ns4
• .nsd
• .nsf
• .nsg
• .nsh
• .nvram
• .nwb
• .nx2
• .nxl
• .nyf
• .oab
• .obj
• .odb
• .odc
• .odf
• .odg
• .odi
• .odm
• .odp
• .ods
• .odt
• .oft
• .oga
• .ogg
• .oil
• .opf
• .orf
• .ost
• .otg
• .oth
• .otp
• .ots
• .ott
• .owl
• .oxt
• .p12
• .p7b
• .p7c
• .pab
• .pages
• .pak
• .pas
• .pat
• .pbf
• .pbp
• .pbs
• .pcd
• .pct
• .pcv
• .pdb
• .pdd
• .pdf
• .pef
• .pem
• .pfx
• .php
• .pif
• .pkb
• .pkh
• .pl
• .plc
• .pli
• .plus_muhd
• .pm
• .png
• .pot
• .potm
• .potx
• .ppam
• .ppd
• .ppf
• .pps
• .ppsm
• .ppsx
• .ppt
• .pptm
• .pptx
• .prc
• .prf
• .prt
• .ps
• .psa
• .psafe3
• .psd
• .pspimage
• .py
• .pst
• .ptx
• .puz
• .pwf
• .pwi
• .pwm
• .pxp
• .py
• .qba
• .qbb
• .qbm
• .qbr
• .qbw
• .qbx
• .qby
• .qcow
• .qcow2
• .qdf
• .qed
• .qel
• .qif
• .qpx
• .qtq
• .qtr
• .r3d
• .ra
• .raf
• .rar
• .rat
• .raw
• .rdb
• .res
• .rev
• .rgn
• .rm
• .rng
• .rrt
• .rsrc
• .rsw
• .rte
• .rtf
• .rts
• .rtx
• .rum
• .run
• .rv
• .rvt
• .rw2
• .rwl
• .rwz
• .s3db
• .sad
• .saf
• .safe
• .sas7bdat
• .sav
• .save
• .say
• .scm
• .scn
• .scx
• .sd0
• .sda
• .sdb
• .sdc
• .sdf
• .sdn
• .sds
• .sdt
• .sen
• .sfs
• .sfx
• .sh
• .shar
• .shr
• .shw
• .sldm
• .sldx
• .slt
• .snp
• .so
• .spr
• .sql
• .sqlite
• .sqlite3
• .sqlitedb
• .sqx
• .sr2
• .srf
• .srt
• .srw
• .ssa
• .st4
• .st5
• .st6
• .st7
• .st8
• .stc
• .std
• .sti
• .stm
• .stt
• .stw
• .stx
• .sud
• .svg
• .svi
• .svr
• .swd
• .swf
• .sxc
• .sxd
• .sxg
• .sxi
• .sxm
• .sxw
• .tar
• .tax2013
• .tax2014
• .tbz2
• .tch
• .tcx
• .tex
• .txt
• .text
• .tg
• .tga
• .thm
• .thmx
• .tif
• .tlg
• .tlz
• .tpu
• .tpx
• .trp
• .tu
• .tur
• .txd
• .txf
• .txt
• .uax
• .udf
• .umx
• .unr
• .unx
• .uop
• .upoi
• .url
• .usa
• .usx
• .ut2
• .ut3
• .utc
• .utx
• .uvx
• .uxx
• .val
• .vbox
• .vc
• .vcd
• .vdi
• .vdo
• .ver
• .vhd
• .vhdx
• .vmdk
• .vmf
• .vmsd
• .vmt
• .vmx
• .vmxf
• .vob
• .vsi
• .vtf
• .w3g
• .w3x
• .wab
• .wad
• .wallet
• .war
• .wav
• .wave
• .waw
• .wb2
• .wbk
• .wdgt
• .wks
• .wm
• .wma
• .wmd
• .wmdb
• .wmmp
• .wmv
• .wmx
• .wow
• .wpd
• .wpk
• .wpl
• .wps
• .wsh
• .wtd
• .wtf
• .wvx
• .x11
• .x3f
• .xis
• .xl
• .xla
• .xlam
• .xlc
• .xlk
• .xll
• .xlm
• .xlr
• .xls
• .xlsb
• .xlsm
• .xlsx
• .xlt
• .xltm
• .xltx
• .xlv
• .xlw
• .xlwx
• .xml
• .xpi
• .xpt
• .xvid
• .xwd
• .yab
• .ycbcra
• .yps
• .yuv
• .z02
• .z04
• .zap
• .zip
• .zipx
• .zoo
• .saz
• .tlp
• .enc
• .bas
• .frm
• .pas
• .vbs
• .json

It encrypts files found in the following folders:

• {All Drives}

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

• AppData
• RECYCLER
• All Users
• Program Files
• Program Files (x86)
• ProgramData
• Windows
• WINDOWS
• system32

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

• {Malware Path}\ReadMe.html
  
• {Encrypted Folder}\ReadMe.txt