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

Win32/Filecoder.HydraCrypt.A [Threat Variant Name]

Category trojan
Size 189440 B
Detection created Feb 04, 2016
Detection database version 12977
Aliases Trojan.Win32.Yakes.noba (Kaspersky)
  Ransom:Win32/Denisca.A (Microsoft)
Short description

Win32/Filecoder.HydraCrypt.A is a trojan that encrypts files on fixed, removable and network drives. To decrypt files the user is requested to comply with given conditions in exchange for a password/instructions.

Installation

When executed, the trojan copies itself into the following location:

  • %appdata%\­UpdSysDrv32Xz32\­%variable%.exe

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


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

  • [HKEY_CURRENT_USER\­SOFTWARE\­Microsoft\­Windows\­CurrentVersion\­Run]
    • "UpdSysDrvX32z32" = "%appdata%\­UpdSysDrv32Xz32\­%variable%.exe"

The trojan may set the following Registry entries:

  • [HKEY_CURRENT_USER\­SOFTWARE\­Microsoft\­Windows]
    • "UpdSysDrvNamxz32" = "%variable%.exe"
    • "UpdSysDrvz23" = "%malwarefilepath%"
    • "TRUECRT32" = "TrueBOSS"
  • [HKEY_CURRENT_USER\­Control Panel\­Desktop]
    • "WallpaperStyle" = "1"
    • "TileWallpaper" = "0"

The trojan may delete the following files:

  • %malwarefilepath%
Information stealing

The trojan collects the following information:

  • volume serial number

The trojan attempts to send gathered information to a remote machine.

Payload information

Win32/Filecoder.HydraCrypt.A is a trojan that encrypts files on fixed, removable and network drives.


The trojan searches for files with the following file extensions:

  • .3fr
  • .7z
  • .accdb
  • .ai
  • .ai
  • .apk
  • .arch00
  • .arw
  • .asset
  • .avi
  • .backup
  • .bar
  • .bay
  • .bc6
  • .bc7
  • .bd
  • .big
  • .bik
  • .bkf
  • .bkp
  • .blob
  • .bmp
  • .bsa
  • .cas
  • .cdr
  • .cer
  • .cfr
  • .cr2
  • .crt
  • .crw
  • .css
  • .csv
  • .d3dbsp
  • .das
  • .dat
  • .dazip
  • .db0
  • .dba
  • .dbf
  • .dcr
  • .der
  • .desc
  • .dmp
  • .dng
  • .doc
  • .docm
  • .docx
  • .dot
  • .dwg
  • .dx
  • .dxg
  • .epk
  • .eps
  • .erf
  • .esm
  • .ff
  • .flv
  • .forge
  • .fos
  • .fpk
  • .fsh
  • .gdb
  • .gho
  • .hkdb
  • .hkx
  • .hplg
  • .hvpl
  • .icxs
  • .indd
  • .itdb
  • .itl
  • .itm
  • .iwd
  • .iwi
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .kdb
  • .kdc
  • .kf
  • .layout
  • .lbf
  • .litemod
  • .lrf
  • .ltx
  • .lvl
  • .m2
  • .m3u
  • .m4a
  • .map
  • .mcmeta
  • .mdb
  • .mdbackup
  • .mddata
  • .mdf
  • .mef
  • .menu
  • .mkv
  • .mlx
  • .mov
  • .mp4
  • .mpqge
  • .mrw
  • .mrwref
  • .ncf
  • .nef
  • .nrw
  • .ntl
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .ods
  • .odt
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pak
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .pkpass
  • .png
  • .pps
  • .ppt
  • .pptm
  • .pptx
  • .psd
  • .psk
  • .pst
  • .ptx
  • .qdf
  • .qic
  • .r3d
  • .raf
  • .rar
  • .raw
  • .rb
  • .re4
  • .rgss3a
  • .rim
  • .rofl
  • .rtf
  • .rw2
  • .rwl
  • .sav
  • .sb
  • .sid
  • .sidd
  • .sidn
  • .sie
  • .sis
  • .slm
  • .snx
  • .sql
  • .sr2
  • .srf
  • .srw
  • .sum
  • .svg
  • .syncdb
  • .t12
  • .t13
  • .tar.gz
  • .tax
  • .tiff
  • .tor
  • .txt
  • .upk
  • .vcf
  • .vdf
  • .vfs0
  • .vpk
  • .vpp_pc
  • .vtf
  • .w3x
  • .wallet
  • .wb2
  • .wma
  • .wmo
  • .wmv
  • .wotreplay
  • .wpd
  • .wps
  • .x3f
  • .xf
  • .xlk
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xml
  • .xxx
  • .zip
  • .ztmp

It avoids files which contain any of the following strings in their path:

  • WINDOWS
  • Windows
  • Program Files
  • Program Files (x86)
  • UpdSysDrv32Xz32

It avoids files with the following extensions:

  • .crypt

The trojan encrypts the file content.


The AES encryption algorithm is used.


The extension of the encrypted files is changed to:

  • .crypt

The password is stored on the attacker's server.


To decrypt files the user is requested to comply with given conditions in exchange for a password/instructions.


The trojan may display the following dialog windows:

The trojan may attempt to download files from the Internet.


The files are stored in the following locations:

  • %appdata%\­UpdSysDrv32Xz32\­UpdSysDrz32.jpg
  • %appdata%\­UpdSysDrv32Xz32\­UpdSyz32.bmp
  • %desktop%\­HELP_DECRYPT.jpg
  • %mydocuments%\­HELP_DECRYPT.jpg
  • %mypictures%\­HELP_DECRYPT.jpg
  • %myvideo%\­HELP_DECRYPT.jpg
  • %mymusic%\­HELP_DECRYPT.jpg
  • %profile%\­Downloads\­HELP_DECRYPT.jpg
  • %desktop%\­!!!
  • %mydocuments%\­!!!
  • %mypictures%\­!!!
  • %myvideo%\­!!!
  • %mymusic%\­!!!
  • %profile%\­Download\­!!!

The trojan contains a list of (3) URLs. The HTTP protocol is used in the communication.

Other information

The trojan creates and runs a new thread with its own program code within the following processes:

  • svchost.exe
  • %malwarefilepath%

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