Ransom.Win32.FORMA.THABABAH

 Analysis by: Jay Garcia

 ALIASES:

Win32:RATX-gen [Trj] (AVAST); HEUR:Trojan.MSIL.HydraPOS.gen (KASPERSKY)

 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:

Dropped by other malware, Downloaded from the Internet

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 adds certain registry entries to disable the Task Manager. This action prevents users from terminating the malware process, which can usually be done via the Task Manager.

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

  TECHNICAL DETAILS

File Size:

1,543,269 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Dec 2018

Payload:

Connects to URLs/IPs, 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 files:

  • %Temp%\wallpaper3.bmp
  • %User Profile%\SystemKey.txt
  • %User Profile%\winsys.txt
  • %User Profile%\winsys2.txt
  • %User Profile%\winsys3.txt

(Note: %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.. %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, 7, and 8.)

It drops and executes the following files:

  • %User Profile%\table.exe
  • %Temp%\1.Bat
  • %Temp%\2.Bat
  • %Temp%\3.Bat
  • %Temp%\4.Bat
  • %Temp%\admin.exe
  • %Temp%\AdobeAcrobatReader.exe
  • %Temp%\invisible.vbs
  • %Temp%\FORMA.exe

(Note: %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, 7, and 8.. %Temp% is the Windows temporary folder, where it usually is C:\Windows\Temp on all Windows operating system versions.)

Autostart Technique

This Ransomware drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • syswin32.lnk

Other System Modifications

This Ransomware adds the following registry entries to disable the Task Manager:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = 1

It changes the desktop wallpaper by modifying the following registry entries:

HKEY_CURRENT_USER\Control Panel\Desktop
wallpaper = %Temp%\wallpaper3.bmp

(Note: The default value data of the said registry entry is {value}.)

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 2

(Note: The default value data of the said registry entry is 0.)

Other Details

This Ransomware does the following:

  • It connects to the following website to download the photo that will be used for the wallpaper:
    • https://{BLOCKED}plik.pl/files/70400aa39abbd947416ab0f48811c848.bmp
  • It locks the screen and display the following:


Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .#vc
  • .$ac
  • .00c
  • .07g
  • .07i
  • .08i
  • .09i
  • .09t
  • .10t
  • .11t
  • .123
  • .13t
  • .1pa
  • .1pe
  • .2011
  • .2012
  • .2013
  • .2014
  • .2015
  • .2016
  • .2017
  • .210
  • .3dm
  • .3ds
  • .3g2
  • .3gp
  • .3me
  • .3pe
  • .500
  • .7z
  • ._vc
  • .aac
  • .aaf
  • .ab4
  • .ac2
  • .acc
  • .accd
  • .ach
  • .aci
  • .acm
  • .acr
  • .aep
  • .aepx
  • .aes
  • .aet
  • .afm
  • .ai
  • .aif
  • .amj
  • .as
  • .as3
  • .asc
  • .asf
  • .asm
  • .asp
  • .asx
  • .ati
  • .avi
  • .back
  • .bak
  • .bay
  • .bc8
  • .bc9
  • .bd2
  • .bd3
  • .bgt
  • .bk2
  • .bkf
  • .bmp
  • .bpf
  • .bpw
  • .brd
  • .brw
  • .btif
  • .bz2
  • .c
  • .cal
  • .cat
  • .cb
  • .cd
  • .cdf
  • .cdr
  • .cdt
  • .cdx
  • .cf8
  • .cf9
  • .cfdi
  • .cfp
  • .cgm
  • .cgn
  • .ch
  • .chg
  • .cht
  • .clas
  • .clk
  • .cmd
  • .cmx
  • .cnt
  • .cntk
  • .coa
  • .cpp
  • .cpt
  • .cpw
  • .cpx
  • .crt
  • .cs
  • .csl
  • .csr
  • .css
  • .csv
  • .cur
  • .cus
  • .d07
  • .dac
  • .dat
  • .db
  • .dbf
  • .dch
  • .dcr
  • .ddd
  • .dds
  • .defx
  • .der
  • .des
  • .dgc
  • .dif
  • .dip
  • .djv
  • .djvu
  • .dng
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .drw
  • .ds4
  • .dsb
  • .dsf
  • .dtau
  • .dtd
  • .dtl
  • .dwg
  • .dxf
  • .dxi
  • .ebc
  • .ebd
  • .ebq
  • .ec8
  • .efs
  • .efsl
  • .efx
  • .emd
  • .eml
  • .emp
  • .ens
  • .ent
  • .epa
  • .epb
  • .eps
  • .eqb
  • .ert
  • .esk
  • .ess
  • .esv
  • .etq
  • .ets
  • .exp
  • .fa1
  • .fa2
  • .fca
  • .fcpa
  • .fcpr
  • .fcr
  • .fef
  • .ffd
  • .fim
  • .fla
  • .flac
  • .flv
  • .fmv
  • .fon
  • .fpx
  • .frm
  • .fx0
  • .fx1
  • .fxr
  • .fxw
  • .fyc
  • .gdb
  • .gem
  • .gfi
  • .gif
  • .gnc
  • .gpc
  • .gpg
  • .gsb
  • .gto
  • .gz
  • .h
  • .h10
  • .h11
  • .h12
  • .hbk
  • .hif
  • .hpp
  • .hsr
  • .html
  • .hts
  • .hwp
  • .i2b
  • .iban
  • .ibd
  • .ico
  • .idml
  • .iff
  • .iif
  • .img
  • .imp
  • .indb
  • .indd
  • .indl
  • .indt
  • .int?
  • .intu
  • .inv
  • .inx
  • .ipe
  • .ipg
  • .itf
  • .jar
  • .java
  • .jng
  • .jp2
  • .jpeg
  • .jpg
  • .js
  • .jsd
  • .jsda
  • .jsp
  • .kb7
  • .kd3
  • .kdc
  • .key
  • .kmo
  • .kmy
  • .lay
  • .lay6
  • .lcd
  • .ldc
  • .ldf
  • .ldr
  • .let
  • .lgb
  • .lhr
  • .lid
  • .lin
  • .lld
  • .lmr
  • .log
  • .lua
  • .lz
  • .m
  • .m10
  • .m11
  • .m12
  • .m14
  • .m15
  • .m16
  • .m3u
  • .m3u8
  • .m4a
  • .m4u
  • .m4v
  • .mac
  • .max
  • .mbsb
  • .md
  • .mda
  • .mdb
  • .mdf
  • .mef
  • .mem
  • .met
  • .meta
  • .mhtm
  • .mid
  • .mkv
  • .ml2
  • .ml9
  • .mlb
  • .mlc
  • .mmb
  • .mml
  • .mmw
  • .mn1
  • .mn2
  • .mn3
  • .mn4
  • .mn5
  • .mn6
  • .mn7
  • .mn8
  • .mn9
  • .mne
  • .mnp
  • .mny
  • .mone
  • .mov
  • .mp2
  • .mp3
  • .mp4
  • .mpa
  • .mpe
  • .mpeg
  • .mpg
  • .mql
  • .mrq
  • .ms11
  • .msg
  • .mwi
  • .mws
  • .mx0
  • .myd
  • .mye
  • .myi
  • .myox
  • .n43
  • .nap
  • .nd
  • .nef
  • .nl2
  • .nni
  • .npc
  • .nv
  • .nv2
  • .oab
  • .obi
  • .odb
  • .odc
  • .odg
  • .odm
  • .odp
  • .ods
  • .odt
  • .oet
  • .ofc
  • .ofx
  • .old
  • .omf
  • .op
  • .orf
  • .ost
  • .otg
  • .otp
  • .ots
  • .ott
  • .p08
  • .p12
  • .p7b
  • .p7c
  • .paq
  • .pas
  • .pat
  • .pcd
  • .pcif
  • .pct
  • .pcx
  • .pd6
  • .pdb
  • .pdd
  • .pdf
  • .pem
  • .per
  • .pfb
  • .pfd
  • .pfx
  • .pg
  • .php
  • .pic
  • .pl
  • .plb
  • .pls
  • .plt
  • .pma
  • .pmd
  • .png
  • .pns
  • .por
  • .pot
  • .potm
  • .potx
  • .pp4
  • .pp5
  • .ppam
  • .ppf
  • .ppj
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptx
  • .pr0
  • .pr1
  • .pr2
  • .pr3
  • .pr4
  • .pr5
  • .prel
  • .prf
  • .prn
  • .prpr
  • .ps
  • .psd
  • .psp
  • .pst
  • .ptb
  • .ptdb
  • .ptk
  • .ptx
  • .pvc
  • .pxa
  • .py
  • .q00
  • .q01
  • .q06
  • .q07
  • .q08
  • .q09
  • .q43
  • .q98
  • .qb1
  • .qb20
  • .qba
  • .qbb
  • .qbi
  • .qbk
  • .qbm
  • .qbmb
  • .qbmd
  • .qbo
  • .qbp
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .qbz
  • .qch
  • .qcow
  • .qdf
  • .qdfx
  • .qdt
  • .qel
  • .qem
  • .qfi
  • .qfx
  • .qif
  • .qix
  • .qme
  • .qml
  • .qmt
  • .qmtf
  • .qnx
  • .qob
  • .qpb
  • .qpd
  • .qpg
  • .qph
  • .qpi
  • .qsd
  • .qsm
  • .qss
  • .qst
  • .qtx
  • .quic
  • .quo
  • .qw5
  • .qwc
  • .qwmo
  • .qxf
  • .r3d
  • .ra
  • .raf
  • .rar
  • .raw
  • .rb
  • .rcs
  • .rda
  • .rdy
  • .reb
  • .rec
  • .resx
  • .rif
  • .rm
  • .rpf
  • .rsspptm
  • .rtf
  • .rtp
  • .rw2
  • .rwl
  • .rz
  • .s12
  • .s7z
  • .saf
  • .saj
  • .say
  • .sba
  • .sbc
  • .sbd
  • .sbf
  • .scd
  • .sch
  • .sct
  • .sdf
  • .sdy
  • .seam
  • .ses
  • .set
  • .shw
  • .sic
  • .skg
  • .sldm
  • .sldx
  • .slk
  • .slp
  • .sql
  • .sqli
  • .sr2
  • .srf
  • .ssg
  • .stc
  • .std
  • .sti
  • .stm
  • .str
  • .stw
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxi
  • .sxm
  • .sxw
  • .t00
  • .t01
  • .t02
  • .t03
  • .t04
  • .t05
  • .t06
  • .t07
  • .t08
  • .t09
  • .t10
  • .t11
  • .t12
  • .t13
  • .t14
  • .t15
  • .t99
  • .ta1
  • .ta2
  • .ta4
  • .ta5
  • .ta6
  • .ta8
  • .ta9
  • .tar
  • .tax
  • .tax0
  • .tax1
  • .tax2
  • .tb2
  • .tbk
  • .tbp
  • .tdr
  • .text
  • .tfx
  • .tga
  • .tgz
  • .tif
  • .tiff
  • .tkr
  • .tlg
  • .tom
  • .tpl
  • .trm
  • .trn
  • .tt10
  • .tt11
  • .tt12
  • .tt13
  • .tt14
  • .tt15
  • .tt20
  • .ttf
  • .txf
  • .txt
  • .u08
  • .u10
  • .u11
  • .u12
  • .uop
  • .uot
  • .v30
  • .vb
  • .vbpf
  • .vbs
  • .vcf
  • .vdf
  • .vdi
  • .vmb
  • .vmdk
  • .vmx
  • .vnd
  • .vob
  • .vsd
  • .vyp
  • .vyr
  • .wac
  • .wav
  • .wb2
  • .wi
  • .wk1
  • .wk3
  • .wk4
  • .wks
  • .wma
  • .wmf
  • .wmv
  • .wpd
  • .wpg
  • .wps
  • .x3f
  • .xaa
  • .xcf
  • .xeq
  • .xhtm
  • .xla
  • .xlam
  • .xlc
  • .xlk
  • .xll
  • .xlm
  • .xlr
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xpm
  • .xqx
  • .yuv
  • .zdb
  • .ziparc
  • .zipx
  • .zix
  • .zka

It encrypts files found in the following folders:

  • %Desktop%
  • %User Profile%\Downloads
  • %Application Data%\Microsoft\Windows\Network Shortcuts

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.. %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, 7, and 8.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

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

  • .locked

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

  • %Desktop%\ODSZYFRFUJ_PLIKI_TERAZ.txt

(Note: %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista, 7, and 8.)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.684.02

FIRST VSAPI PATTERN DATE:

12 Dec 2018

VSAPI OPR PATTERN File:

14.685.00

VSAPI OPR PATTERN Date:

13 Dec 2018

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

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.
  • %User Startup%\syswin32.lnk
  • %Desktop%\ODSZYFRFUJ_PLIKI_TERAZ.txt
  • %User Profile%\SystemKey.txt
  • %User Profile%\winsys.txt
  • %User Profile%\winsys2.txt
  • %User Profile%\winsys3.txt
  • %User Profile%\table.exe
  • %Temp%\1.Bat
  • %Temp%\2.Bat
  • %Temp%\3.Bat
  • %Temp%\4.Bat
  • %Temp%\admin.exe
  • %Temp%\AdobeAcrobatReader.exe
  • %Temp%\invisible.vbs
  • %Temp%\FORMA.exe
  • %Temp%\wallpaper3.bmp

Step 5

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System
    • DisableTaskMgr = 1

Step 6

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: wallpaper = %Temp%\wallpaper3.bmp
      To: wallpaper = {value}
  • In HKEY_CURRENT_USER\Control Panel\Desktop
    • From: WallpaperStyle = 2
      To: WallpaperStyle = 0

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Ransom.Win32.FORMA.THABABAH. 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 8

Restore encrypted files from backup.


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