RANSOM_LOCKY.DLDTASL

 Analysis by: Ryan Paolo Maglaque

 ALIASES:

Trojan-Ransom.Win32.Locky.xlz(Kaspersky);Troj/Locky-ZI(Sophos);W32/Locky.FOGX!tr(Fortinet)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This Trojan 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

261,120 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

14 Feb 2017

Payload:

Displays message/message boxes, Connects to URLs/IPs, Encrypts files

Arrival Details

This Trojan 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 Trojan drops the following files:

  • (Folder of Encrypted Files}\OSIRIS-{Random Hex Values}.htm → Ransom Note

It drops and executes the following files:

  • %User Profile%\DesktopOSIRIS.bmp → Ransom Note, image used as wallpaper
  • %User Profile%\DesktopOSIRIS.htm → Ransom Note

(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 and 7.)

Other System Modifications

This Trojan modifies the following file(s):

  • It encrypts files in fixed, removable, RAM disk drives, and network shares.

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Control Panel\Desktop
WallpaperStyle = 0

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

HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = 0

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

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %User Profile%\DesktopOSIRIS.bmp

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

It sets the system's desktop wallpaper to the following image:

Other Details

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

  • http://{BLOCKED}.{BLOCKED}.217.65/checkupdate
  • http://{BLOCKED}.{BLOCKED}.28.162/checkupdate

It encrypts files with the following extensions:

  • .001
  • .002
  • .003
  • .004
  • .005
  • .006
  • .007
  • .008
  • .009
  • .010
  • .011
  • .123
  • .1cd
  • .3dm
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .3pr
  • .602
  • .7z
  • .7zip
  • .aac
  • .ab4
  • .accdb
  • .accde
  • .accdr
  • .accdt
  • .ach
  • .acr
  • .act
  • .adb
  • .adp
  • .ads
  • .aes
  • .agdl
  • .ai
  • .aiff
  • .ait
  • .al
  • .aoi
  • .apj
  • .apk
  • .ARC
  • .arw
  • .asc
  • .asf
  • .asm
  • .asp
  • .aspx
  • .asset
  • .asx
  • .avi
  • .awg
  • .back
  • .backup
  • .backupdb
  • .bak
  • .bank
  • .bat
  • .bay
  • .bdb
  • .bgt
  • .bik
  • .bin
  • .bkp
  • .blend
  • .bmp
  • .bpw
  • .brd
  • .bsa
  • .bz2
  • .c
  • .cdf
  • .cdr
  • .cdr3
  • .cdr4
  • .cdr5
  • .cdr6
  • .cdrw
  • .cdx
  • .ce1
  • .ce2
  • .cer
  • .cfg
  • .cgm
  • .cib
  • .class
  • .cls
  • .cmd
  • .cmt
  • .config
  • .contact
  • .cpi
  • .cpp
  • .cr2
  • .craw
  • .crt
  • .crw
  • .cs
  • .csh
  • .csl
  • .csr
  • .css
  • .csv
  • .CSV
  • .d3dbsp
  • .dac
  • .das
  • .dat
  • .db
  • .db_journal
  • .db3
  • .dbf
  • .dbx
  • .dc2
  • .dch
  • .dcr
  • .dcs
  • .ddd
  • .ddoc
  • .ddrw
  • .dds
  • .der
  • .des
  • .design
  • .dgc
  • .dif
  • .dip
  • .dit
  • .djv
  • .djvu
  • .dng
  • .doc
  • .DOC
  • .docb
  • .docm
  • .docx
  • .dot
  • .DOT
  • .dotm
  • .dotx
  • .drf
  • .drw
  • .dtd
  • .dwg
  • .dxb
  • .dxf
  • .dxg
  • .edb
  • .eml
  • .eps
  • .erbsql
  • .erf
  • .exf
  • .fdb
  • .ffd
  • .fff
  • .fh
  • .fhd
  • .fla
  • .flac
  • .flf
  • .flv
  • .flvv
  • .forge
  • .fpx
  • .frm
  • .fxg
  • .gif
  • .gpg
  • .gray
  • .grey
  • .groups
  • .gry
  • .gz
  • .h
  • .hbk
  • .hdd
  • .hpp
  • .html
  • .hwp
  • .ibank
  • .ibd
  • .ibz
  • .idx
  • .iif
  • .iiq
  • .incpas
  • .indd
  • .iwi
  • .jar
  • .java
  • .jnt
  • .jpe
  • .jpeg
  • .jpg
  • .js
  • .kc2
  • .kdbx
  • .kdc
  • .key
  • .kpdx
  • .kwm
  • .laccdb
  • .lay
  • .lay6
  • .lbf
  • .ldf
  • .lit
  • .litemod
  • .litesql
  • .log
  • .ltx
  • .lua
  • .m
  • .m2ts
  • .m3u
  • .m4a
  • .m4p
  • .m4u
  • .m4v
  • .mapimail
  • .max
  • .mbx
  • .md
  • .mdb
  • .mdc
  • .mdf
  • .mef
  • .mfw
  • .mid
  • .mkv
  • .mlb
  • .mml
  • .mmw
  • .mny
  • .moneywell
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mrw
  • .ms11
  • .ms11 (Security copy)
  • .msg
  • .myd
  • .MYD
  • .MYI
  • .n64
  • .nd
  • .ndd
  • .ndf
  • .nef
  • .NEF
  • .nk2
  • .nop
  • .nrw
  • .ns2
  • .ns3
  • .ns4
  • .nsd
  • .nsf
  • .nsg
  • .nsh
  • .nvram
  • .nwb
  • .nx2
  • .nxl
  • .nyf
  • .oab
  • .obj
  • .odb
  • .odc
  • .odf
  • .odg
  • .odm
  • .odp
  • .ods
  • .odt
  • .ogg
  • .oil
  • .onetoc2
  • .orf
  • .ost
  • .otg
  • .oth
  • .otp
  • .ots
  • .ott
  • .p12
  • .p7b
  • .p7c
  • .pab
  • .pages
  • .PAQ
  • .pas
  • .pat
  • .pcd
  • .pct
  • .pdb
  • .pdd
  • .pdf
  • .pef
  • .pem
  • .pfx
  • .php
  • .pif
  • .pl
  • .plc
  • .plus_muhd
  • .png
  • .pot
  • .potm
  • .potx
  • .ppam
  • .pps
  • .ppsm
  • .ppsx
  • .ppt
  • .PPT
  • .pptm
  • .pptx
  • .prf
  • .ps
  • .psafe3
  • .psd
  • .pspimage
  • .pst
  • .ptx
  • .pwm
  • .py
  • .qba
  • .qbb
  • .qbm
  • .qbr
  • .qbw
  • .qbx
  • .qby
  • .qcow
  • .qcow2
  • .qed
  • .r3d
  • .raf
  • .rar
  • .rat
  • .raw
  • .rb
  • .rdb
  • .re4
  • .rm
  • .RTF
  • .rtf
  • .rvt
  • .rw2
  • .rwl
  • .rwz
  • .s3db
  • .safe
  • .sas7bdat
  • .sav
  • .save
  • .say
  • .sch
  • .sd0
  • .sda
  • .sdf
  • .sh
  • .sldm
  • .sldx
  • .slk
  • .sql
  • .sqlite
  • .sqlite3
  • .SQLITE3
  • .sqlitedb
  • .SQLITEDB
  • .sr2
  • .srf
  • .srt
  • .srw
  • .st4
  • .st5
  • .st6
  • .st7
  • .st8
  • .stc
  • .std
  • .sti
  • .stm
  • .stw
  • .stx
  • .svg
  • .swf
  • .sxc
  • .sxd
  • .sxg
  • .sxi
  • .sxm
  • .sxw
  • .tar
  • .tar
  • .tbk
  • .tex
  • .tga
  • .tgz
  • .thm
  • .tif
  • .tiff
  • .tlg
  • .txt
  • .uop
  • .uot
  • .upk
  • .vb
  • .vbox
  • .vbs
  • .vdi
  • .vhd
  • .vhdx
  • .vmdk
  • .vmsd
  • .vmx
  • .vmxf
  • .vob
  • .wab
  • .wad
  • .wallet
  • .wav
  • .wb2
  • .wk1
  • .wks
  • .wma
  • .wmv
  • .wpd
  • .wps
  • .x11
  • .x3f
  • .xis
  • .xla
  • .xlam
  • .xlc
  • .xlk
  • .xlm
  • .xlr
  • .xls
  • .XLS
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .ycbcra
  • .yuv
  • .zip
  • wallet.dat

It renames encrypted files using the following names:

  • {first 8 characters of ID}--{next 4 characters of ID}--{last 4 characters of ID}--{8 hex characters}--{12 hex characters}.osiris

It does the following:

  • It prevents encrypting files containing any of the strings in its full path name:
    • $Recycle.Bin
    • _HELP_instructions.bmp
    • _HELP_instructions.html
    • _HELP_instructions.txt
    • _Locky_recover_instructions.bmp
    • _Locky_recover_instructions.txt
    • AppData
    • Application Data
    • Boot
    • Program Files
    • Program Files (x86)
    • System Volume Information
    • temp
    • thumbs.db
    • tmp
    • Windows
    • winnt
  • It deletes shadow copies by executing the following command:
    • vssadmin.exe Delete Shadows /Quiet /All
  • It drops the following ransom note:

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.220.04

FIRST VSAPI PATTERN DATE:

14 Feb 2017

VSAPI OPR PATTERN File:

13.221.00

VSAPI OPR PATTERN Date:

15 Feb 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 this file

[ 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.  
  • (Folder of Encrypted Files}\OSIRIS-{Random Hex Values}.htm
  • %User Profile%\DesktopOSIRIS.bmp
  • %User Profile%\DesktopOSIRIS.htm

Step 4

Reset your Desktop properties

[ Learn More ]

Step 5

Scan your computer with your Trend Micro product to delete files detected as RANSOM_LOCKY.DLDTASL. 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.


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