RANSOM_KARO.A

 Modified by: Byron Jon Gelera

 ALIASES:

Ransom:Win32/HiddenTear (Microsoft); Ransom.Cryptolocker (Symantec); Trojan.Win32.TorJok.l (Kaspersky)

 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 connects to certain websites to send and receive information.

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

  TECHNICAL DETAILS

File Size:

798,720 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

27 Jun 2017

Payload:

Connects to URLs/IPs, Downloads files, Encrypts files, Displays graphics/image, Displays message/message boxes

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%\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 drops the following files:

  • %Application Data%\aes

(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:

  • %User Temp%\Tor ← contains Tor browser components

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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:

  • MyUniqueMutexName

Autostart Technique

This Ransomware drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\Notepad.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other System Modifications

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

Download Routine

This Ransomware connects to the following URL(s) to download its component file(s):

  • https://{BLOCKED}t.{BLOCKED}ject.org/torbrowser/7.0.1/tor-win32-0.3.0.8.zip (Tor Browser)
  • http://{BLOCKED}4eayyxjc4j.onion/wall.png (Ransom Note Wallpaper)

It saves the files it downloads using the following names:

  • %User Temp%\{5 random characters}.zip ← Tor Browser Package
  • %User Temp%\{5 random characters}.jpg ← Ransom Note Wallpaper

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

Other Details

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

  • http://{BLOCKED}4eayyxjc4j.onion/control.php?uid={value}&uname={value}&os={value}&pcname={value}
  • http://{BLOCKED}4eayyxjc4j.onion/controller.php?uid={value}&aes={value}
  • http://{BLOCKED}4eayyxjc4j.onion/total.php?uid={value}&total={value}

It does the following:

  • It checks for virtual environment by checking the presence of the following strings:
    • virtual
    • vmware
    • VirtualBox
    Once found, It will execute the following process before terminating:
    • %System%\cmd.exe /c PING -n 5 127.0.0.1 & del /f /q "%temp%\*.*
  • It checks if the following module is loaded in its process as an anti-sandbox technique:
    • SbieDLL.dll
  • It execute the following commands:
    • %System%\cmd.exe icacls %User Temp% /grant Everyone:F /T /C /Q (Grants Permission to %User Temp% for all Users)
    • %User Temp%\Tor\Microsoft.vshub.32.exe" -f .\torrc (Executes Tor Browser)
    • %System%\cmd.exe" /c taskkill.exe /f /im Microsoft.Exchange.*
    • %System%\cmd.exe" /c taskkill.exe /f /im MSExchange*
    • %System%\cmd.exe" /c taskkill.exe /f /im sqlserver.exe
    • %System%\cmd.exe" /c taskkill.exe /f /im sqlwriter.exe
    • %System%\cmd.exe" /c taskkill.exe /f /im mysqld.exe
    • %System%\cmd.exe /c taskkill.exe /f /im Microsoft.vshub.32.exe.*
    • %System%\cmd.exe /c PING -n 5 127.0.0.1 & del /f /q "%temp%\*.* (Deletes all files under %User Temp% directory
  • The following are Tor Browser components installed by this ransomware:
    • %User Temp%\Tor\libeay32.dll
    • %User Temp%\Tor\libevent-2-0-5.dll
    • %User Temp%\Tor\libevent_core-2-0-5.dll
    • %User Temp%\Tor\libevent_extra-2-0-5.dll
    • %User Temp%\Tor\libgcc_s_sjlj-1.dll
    • %User Temp%\Tor\libssp-0.dll
    • %User Temp%\Tor\ssleay32.dll
    • %User Temp%\Tor\tor-gencert.exe
    • %User Temp%\Tor\Microsoft.vshub.32.exe -> (renamed from tor.exe)
    • %User Temp%\Tor\zlib1.dll
    • %User Temp%\Tor\torrc

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .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

It encrypts files found in the following folders:

  • All folders under All Fixed Drives Except %System Root%
  • %Desktop%
  • %User Profile%\Pictures
  • %User Profile%\Music
  • %User Profile%\Documents

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

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

  • .ipygh

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

  • %Desktop%\ReadMe.html

(Note: %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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.)

NOTES:
The ransom note ReadMe.html contains the following:

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.500.07

FIRST VSAPI PATTERN DATE:

28 Jun 2017

VSAPI OPR PATTERN File:

13.501.00

VSAPI OPR PATTERN Date:

29 Jun 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

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\Tor

Step 4

Search and delete these files

[ 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%\aes
  • %User Startup%\Notepad.lnk
  • %User Temp%\{5 random characters}.zip
  • %User Temp%\{5 random characters}.jpg
  • %Desktop%\ReadMe.html

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_KARO.A. 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 6

Restore encrypted files from backup.

Step 7

Reset your Desktop properties

[ Learn More ]


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