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RANSOM_TROLDESH.R01FC0DKL18

January 09, 2019
 Analysis by: Henry Alarcon Jr.
 ALIASES:

Trojan-Ransom.Win32.Shade.pbw (Kaspersky), Ransom:Win32/Troldesh.A (Microsoft ), Ransom.Troldesh (Symantec)

 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 connects to certain websites to send and receive information.

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

  TECHNICAL DETAILS

File Size:

1,352,968 bytes

File Type:

EXE

File Compression:

UPX

Memory Resident:

No

Payload:

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

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:

  • %All Users Profile%\Application Data\Windows\csrss.exe (Windows XP and below)
  • %All Users Profile%\Windows\csrss.exe (Windows Vista and above)

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. )

It drops the following files:

  • %User Temp%\{random}\lock
  • %User Temp%\{random}\state
  • %User Temp%\{random}\unverified-microdesc-consensus
  • %User Temp%\{random}\cached-certs
  • %User Temp%\{random}\cached-microdesc-consensus
  • %User Temp%\{random}\cached-microdescs.new
  • %Application Data%\{Random characters}.bmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp 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 adds the following processes:

  • C:\Windows\system32\vssadmin.exe List Shadows
  • C:\Windows\system32\vssadmin.exe Delete Shadows /All /Quiet

Autostart Technique

This Ransomware adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Client Server Runtime Subsystem = "%All Users Profile%\Application Data\Windows\csrss.exe (Windows XP and below)"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Client Server Runtime Subsystem = "%All Users Profile%\Windows\csrss.exe (Windows Vista and above)"

Other System Modifications

This Ransomware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xVersion = "4.0.0.1"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xpk = "{PUBLIC KEY}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xmode = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xi = "{Random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xstate = {number}

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
xcnt = "{number}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
shsnt = "{number}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
shst = "{number}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
sh1 = "{number}"

HKEY_LOCAL_MACHINE\SOFTWARE\System32\
Configuration
sh2 = "{number}"

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

HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = %Application Data%\{Random characters}.bmp

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

Other Details

This Ransomware connects to the following URL(s) to get the affected system's IP address:

  • http://whatismyipaddress.com/
  • http://whatsmyip.net/

It connects to the following website to send and receive information:

  • http://{BLOCKED}p2xzclh6fd.onion/{path}
    where {path} can be any of the following:
    • reg.php
    • prog.php
    • err.php
    • cmd.php
    • sys.php
    • shd.php
    • mail.php

Ransomware Routine

This Ransomware encrypts files with the following extensions:

  • .1cd
  • .3ds
  • .3fr
  • .3g2
  • .3gp
  • .7z
  • .accda
  • .accdb
  • .accdc
  • .accde
  • .accdt
  • .accdw
  • .adb
  • .adp
  • .ai
  • .ai3
  • .ai4
  • .ai5
  • .ai6
  • .ai7
  • .ai8
  • .anim
  • .arw
  • .as
  • .asa
  • .asc
  • .ascx
  • .asm
  • .asmx
  • .asp
  • .aspx
  • .asr
  • .asx
  • .avi
  • .avs
  • .backup
  • .bak
  • .bay
  • .bd
  • .bin
  • .bmp
  • .bz2
  • .c
  • .cbf
  • .cdr
  • .cer
  • .cf
  • .cfc
  • .cfm
  • .cfml
  • .cfu
  • .chm
  • .cin
  • .class
  • .clx
  • .config
  • .cpp
  • .cr2
  • .crt
  • .crw
  • .crypted
  • .cs
  • .css
  • .csv
  • .cub
  • .dae
  • .dat
  • .db
  • .dbf
  • .dbx
  • .dc3
  • .dcm
  • .dcr
  • .der
  • .dib
  • .dic
  • .dif
  • .divx
  • .djvu
  • .dmp
  • .dng
  • .doc
  • .docm
  • .docx
  • .dot
  • .dotm
  • .dotx
  • .dpx
  • .dqy
  • .dsn
  • .dt
  • .dtd
  • .dwg
  • .dwt
  • .dx
  • .dxf
  • .edml
  • .efd
  • .elf
  • .emf
  • .eml
  • .emz
  • .epf
  • .eps
  • .epsf
  • .epsp
  • .erf
  • .exr
  • .f4v
  • .fbk
  • .fdb
  • .fido
  • .fld
  • .flm
  • .flv
  • .frm
  • .fxg
  • .geo
  • .gif
  • .grs
  • .gz
  • .h
  • .hdr
  • .hpp
  • .hta
  • .htc
  • .htm
  • .html
  • .icb
  • .ics
  • .iff
  • .inc
  • .indd
  • .ini
  • .iqy
  • .j2c
  • .j2k
  • .java
  • .jp2
  • .jpc
  • .jpe
  • .jpeg
  • .jpf
  • .jpg
  • .jpx
  • .js
  • .jsf
  • .json
  • .jsp
  • .kdc
  • .kmz
  • .kwm
  • .lasso
  • .lbi
  • .lgf
  • .lgp
  • .log
  • .lst
  • .m1v
  • .m4a
  • .m4v
  • .max
  • .md
  • .mda
  • .mdb
  • .mde
  • .mdf
  • .mdw
  • .mef
  • .mft
  • .mfw
  • .mht
  • .mhtml
  • .mka
  • .mkidx
  • .mkv
  • .mos
  • .mov
  • .mp3
  • .mp4
  • .mpeg
  • .mpg
  • .mpv
  • .mrw
  • .msg
  • .mtr
  • .mxl
  • .myd
  • .myi
  • .nef
  • .nrw
  • .obj
  • .odb
  • .odc
  • .odm
  • .odp
  • .ods
  • .oft
  • .one
  • .onepkg
  • .onetoc2
  • .opt
  • .oqy
  • .orf
  • .p12
  • .p7b
  • .p7c
  • .pam
  • .pbm
  • .pct
  • .pcx
  • .pdd
  • .pdf
  • .pdp
  • .pef
  • .pem
  • .pff
  • .pfm
  • .pfx
  • .pgm
  • .php
  • .php3
  • .php4
  • .php5
  • .phtml
  • .pict
  • .pl
  • .pls
  • .pm
  • .png
  • .pnm
  • .pot
  • .potm
  • .potx
  • .ppa
  • .ppam
  • .ppm
  • .pps
  • .ppsm
  • .ppt
  • .pptm
  • .pptx
  • .prn
  • .ps
  • .psb
  • .psd
  • .pst
  • .ptx
  • .pub
  • .pwm
  • .pxr
  • .py
  • .qt
  • .r3d
  • .raf
  • .rar
  • .raw
  • .rdf
  • .rgbe
  • .rle
  • .rqy
  • .rss
  • .rtf
  • .rw2
  • .rwl
  • .safe
  • .sct
  • .sdpx
  • .shtm
  • .shtml
  • .slk
  • .sln
  • .sql
  • .sr2
  • .srf
  • .srw
  • .ssi
  • .st
  • .stm
  • .svg
  • .svgz
  • .swf
  • .tab
  • .tar
  • .tbb
  • .tbi
  • .tbk
  • .tdi
  • .tga
  • .thmx
  • .tib
  • .tif
  • .tiff
  • .tld
  • .torrent
  • .tpl
  • .txt
  • .u3d
  • .udl
  • .uxdc
  • .vault
  • .vb
  • .vbk
  • .vbm
  • .vbs
  • .vcs
  • .vda
  • .vdr
  • .vdw
  • .vdx
  • .vhd
  • .vib
  • .vrp
  • .vsd
  • .vss
  • .vst
  • .vsw
  • .vsx
  • .vtm
  • .vtml
  • .vtx
  • .wav
  • .wb2
  • .wbm
  • .wbmp
  • .wim
  • .wmf
  • .wml
  • .wmv
  • .wpd
  • .wps
  • .x3f
  • .xl
  • .xla
  • .xlam
  • .xlk
  • .xlm
  • .xls
  • .xlsb
  • .xlsm
  • .xlsx
  • .xlt
  • .xltm
  • .xltx
  • .xlw
  • .xml
  • .xps
  • .xsd
  • .xsf
  • .xsl
  • .xslt
  • .xsn
  • .xtp
  • .xtp2
  • .xyze
  • .xz
  • .zip

It renames encrypted files using the following names:

  • {random characters}.{ID}.crypted000007

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

  • {Drive letter}:\README{1-10}.txt
  • %Desktop%\README{1-10}.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.)

It leaves text files that serve as ransom notes containing the following text:

  SOLUTION

Minimum Scan Engine:

9.850

VSAPI OPR PATTERN File:

14.641.00

VSAPI OPR PATTERN Date:

21 Nov 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

Identify and terminate files detected as RANSOM_TROLDESH.R01FC0DKL18

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

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_LOCAL_MACHINE\SOFTWARE\System32
    • Configuration

Step 5

Delete this registry value

[ 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\Run
    • Client Server Runtime Subsystem = "%All Users Profile%\Application Data\Windows\csrss.exe (Windows XP and below)"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Client Server Runtime Subsystem = "%All Users Profile%\Windows\csrss.exe (Windows Vista and above)"

Step 6

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 Temp%\{random}\lock
  • %User Temp%\{random}\state
  • %User Temp%\{random}\unverified-microdesc-consensus
  • %User Temp%\{random}\cached-certs
  • %User Temp%\{random}\cached-microdesc-consensus
  • %User Temp%\{random}\cached-microdescs.new
  • %Application Data%\{Random characters}.bmp
  • {Drive letter}:\README{1-10}.txt
  • %Desktop%\README{1-10}.txt

Step 7

Restore encrypted files from backup.

Step 8

Reset your Desktop properties

[ Learn More ]

Step 9

Scan your computer with your Trend Micro product to delete files detected as RANSOM_TROLDESH.R01FC0DKL18. 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 the following Trend Micro Support pages for more information:


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