Win32/Filecoder.WannaCryptor [Threat Name] go to Threat

Win32/Filecoder.WannaCryptor.D [Threat Variant Name]

Category trojan
Detection created May 12, 2017
Signature database version 15404
Aliases Ransom:Win32/WannaCrypt (Microsoft)
  Troj/Wanna-H (Sophos)
  Ransom-WannaCry (McAfee)
Short description

Win32/Filecoder.WannaCryptor.D is a trojan that encrypts files on local drives. To decrypt files, the user is asked to send information/certain amount of money via the Bitcoin payment service.

Installation

The trojan is usually a part of other malware with name Win32/Exploit.CVE-2017-0147.A .


When executed the trojan drops in folder %malwarefolder% the following file:

  • tasksche.exe (Win32/Filecoder.WannaCryptor.D)

The %malwarefolder% is one of the following strings:

  • %programdata%\­%variable%
  • %systemdrive%\­intel\­%variable%
  • %systemroot%
  • %currentfolder%

A string with variable content is used instead of %variable% .


The trojan creates the following files:

  • %malwarefolder%\­@WanaDecryptor@.exe
  • %malwarefolder%\­taskdl.exe (Win32/Filecoder.WannaCryptor.D)
  • %malwarefolder%\­taskse.exe (Win32/Filecoder.WannaCryptor.D)
  • %malwarefolder%\­%randomnumber%.bat
  • %malwarefolder%\­@Please_Read_Me@.txt
  • %malwarefolder%\­@WanaDecryptor@.bmp
  • %malwarefolder%\­00000000.eky
  • %malwarefolder%\­00000000.pky
  • %malwarefolder%\­00000000.res
  • %malwarefolder%\­b.wnry
  • %malwarefolder%\­c.wnry
  • %malwarefolder%\­f.wnry
  • %malwarefolder%\­r.wnry
  • %malwarefolder%\­s.wnry
  • %malwarefolder%\­t.wnry
  • %malwarefolder%\­u.wnry
  • %malwarefolder%\­m.vbs
  • %malwarefolder%\­msg\­m_bulgarian.wnry
  • %malwarefolder%\­msg\­m_chinese (simplified).wnry
  • %malwarefolder%\­msg\­m_chinese (traditional).wnry
  • %malwarefolder%\­msg\­m_croatian.wnry
  • %malwarefolder%\­msg\­m_czech.wnry
  • %malwarefolder%\­msg\­m_danish.wnry
  • %malwarefolder%\­msg\­m_dutch.wnry
  • %malwarefolder%\­msg\­m_english.wnry
  • %malwarefolder%\­msg\­m_filipino.wnry
  • %malwarefolder%\­msg\­m_finnish.wnry
  • %malwarefolder%\­msg\­m_french.wnry
  • %malwarefolder%\­msg\­m_german.wnry
  • %malwarefolder%\­msg\­m_greek.wnry
  • %malwarefolder%\­msg\­m_indonesian.wnry
  • %malwarefolder%\­msg\­m_italian.wnry
  • %malwarefolder%\­msg\­m_japanese.wnry
  • %malwarefolder%\­msg\­m_korean.wnry
  • %malwarefolder%\­msg\­m_latvian.wnry
  • %malwarefolder%\­msg\­m_norwegian.wnry
  • %malwarefolder%\­msg\­m_polish.wnry
  • %malwarefolder%\­msg\­m_portuguese.wnry
  • %malwarefolder%\­msg\­m_romanian.wnry
  • %malwarefolder%\­msg\­m_russian.wnry
  • %malwarefolder%\­msg\­m_slovak.wnry
  • %malwarefolder%\­msg\­m_spanish.wnry
  • %malwarefolder%\­msg\­m_swedish.wnry
  • %malwarefolder%\­msg\­m_turkish.wnry
  • %malwarefolder%\­msg\­m_vietnamese.wnry
  • %malwarefolder%\­TaskData\­Tor\­libeay32.dll
  • %malwarefolder%\­TaskData\­Tor\­libevent-2-0-5.dll
  • %malwarefolder%\­TaskData\­Tor\­libevent_core-2-0-5.dll
  • %malwarefolder%\­TaskData\­Tor\­libevent_extra-2-0-5.dll
  • %malwarefolder%\­TaskData\­Tor\­libgcc_s_sjlj-1.dll
  • %malwarefolder%\­TaskData\­Tor\­libssp-0.dll
  • %malwarefolder%\­TaskData\­Tor\­ssleay32.dll
  • %malwarefolder%\­TaskData\­Tor\­taskhsvc.exe
  • %malwarefolder%\­TaskData\­Tor\­tor.exe
  • %malwarefolder%\­TaskData\­Tor\­zlib1.dll

A string with variable content is used instead of %randomnumber% .


In order to be executed on every system start, the trojan sets the following Registry entries:

  • [HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\­Windows\­CurrentVersion\­Run]
    • "%variable%" = "%malwarefolder%\­tasksche.exe"

The following Registry entries are created:

  • [HKEY_LOCAL_MACHINE\­SOFTWARE\­WanaCrypt0r]
    • "wd" = "%malwarefolder%"
  • [HKEY_CURRENT_USER\­Control Panel\­Desktop
    • "Wallpaper" = "%malwarefolder%\­@WanaDecryptor@.bmp"
Payload information

Win32/Filecoder.WannaCryptor.D is a trojan that encrypts files on local drives.


The trojan searches local drives for files with the following file extensions:

  • .123
  • .3dm
  • .3ds
  • .3g2
  • .3gp
  • .602
  • .7z
  • .accdb
  • .aes
  • .ai
  • .ARC
  • .asc
  • .asf
  • .asm
  • .asp
  • .avi
  • .backup
  • .bak
  • .bat
  • .bmp
  • .brd
  • .bz2
  • .c
  • .cgm
  • .class
  • .cmd
  • .cpp
  • .crt
  • .cs
  • .csr
  • .csv
  • .db
  • .dbf
  • .dch
  • .der
  • .dif
  • .dip
  • .djvu
  • .doc
  • .docb
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dwg
  • .edb
  • .eml
  • .fla
  • .flv
  • .frm
  • .gif
  • .gpg
  • .gz
  • .h
  • .hwp
  • .ibd
  • .iso
  • .jar
  • .java
  • .jpeg
  • .jpg
  • .js
  • .jsp
  • .key
  • .lay
  • .lay6
  • .ldf
  • .m3u
  • .m4u
  • .max
  • .mdb
  • .mdf
  • .mid
  • .mkv
  • .mml
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .msg
  • .myd
  • .myi
  • .nef
  • .odb
  • .odg
  • .odp
  • .ods
  • .odt
  • .onetoc2
  • .ost
  • .otg
  • .otp
  • .ots
  • .ott
  • .p12
  • .PAQ
  • .pas
  • .pdf
  • .pem
  • .pfx
  • .php
  • .pl
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .pptm
  • .pptx
  • .ps1
  • .psd
  • .pst
  • .rar
  • .raw
  • .rb
  • .rtf
  • .sch
  • .sh
  • .sldm
  • .sldm
  • .sldx
  • .slk
  • .sln
  • .snt
  • .sql
  • .sqlite3
  • .sqlitedb
  • .stc
  • .std
  • .sti
  • .stw
  • .suo
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tbk
  • .tgz
  • .tif
  • .tiff
  • .txt
  • .uop
  • .uot
  • .vb
  • .vbs
  • .vcd
  • .vdi
  • .vmdk
  • .vmx
  • .vob
  • .vsd
  • .vsdx
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .xlc
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .zip

The trojan encrypts the file content.


The extension of the encrypted files is changed to:

  • %filepath%.WNCRY

The RSA, AES encryption algorithm is used.


To decrypt files, the user is asked to send information/certain amount of money via the Bitcoin payment service.


Some examples follow.

Other information

When searching the drives, the trojan creates the following file in every folder visited:

  • @WanaDecryptor@.exe.lnk

The file is a shortcut to a following file:

  • %malwarefolder%\­@WanaDecryptor@.exe

The following file is dropped in the same folder:

  • @Please_Read_Me@.txt

It contains the following text:

  • Q:  What's wrong with my files?
  • A:  Ooops, your important files are encrypted. It means you will not be able to access them anymore until they are decrypted.
  • If you follow our instructions, we guarantee that you can decrypt all your files quickly and safely!
  • Let's start decrypting!
  • Q:  What do I do?
  • A:  First, you need to pay service fees for the decryption.
  • Please send $300 worth of bitcoin to this bitcoin address: 12t9YDPgwueZ9NyMgw519p7AA8isjr6SMw
  • Next, please find an application file named "@WanaDecryptor@.exe". It is the decrypt software.
  • Run and follow the instructions! (You may need to disable your antivirus for a while.)
  • Q:  How can I trust?
  • A:  Don't worry about decryption.
  • We will decrypt your files surely because nobody will trust us if we cheat users.
  • *   If you need our assistance, send a message by clicking  on the decryptor window.

The trojan executes the following commands:

  • cmd.exe /c vssadmin delete shadows /all /quiet & wmic shadowcopy delete & bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no & wbadmin delete catalog -quiet
  • icacls . /grant Everyone:F /T /C /Q
  • attrib +h .

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