Analysis by: Ryan Paolo Maglaque
ALIASES:

Troj/CrWire-A(Sophos);Trojan-Ransom.Win32.Gen.dke(Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Ransomware

  • Destructiveness: No

  • Encrypted: No

  • 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 uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

  TECHNICAL DETAILS

File Size: 895,488 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 Mar 2017
Payload: Encrypts files, Drops 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 files:

  • %Program Files%\Common Files\{Random Numbers} ← Bitcoin amount
  • %Program Files%\Common Files\{Random Numbers}
  • %Program Files%\Common Files\log.txt ← list of encrypted files

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\{Malware Name}

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Autostart Technique

The scheduled task executes the malware every:

  • Onlogon

Other Details

This Ransomware encrypts files with the following extensions:

  • .zip
  • .7z
  • .rar
  • .pdf
  • .doc
  • .docx
  • .xls
  • .xlsx
  • .pptx
  • .pub
  • .one
  • .vsdx
  • .accdb
  • .asd
  • .xlsb
  • .mdb
  • .snp
  • .wbk
  • .ppt
  • .psd
  • .ai
  • .odt
  • .ods
  • .odp
  • .odm
  • .odc
  • .odb
  • .docm
  • .wps
  • .xlsm
  • .xlk
  • .pptm
  • .pst
  • .dwg
  • .dxf
  • .dxg
  • .wpd
  • .rtf
  • .wb2
  • .mdf
  • .dbf
  • .pdd
  • .eps
  • .indd
  • .cdr
  • .dng
  • .3fr
  • .arw
  • .srf
  • .sr2
  • .bay
  • .crw
  • .cr2
  • .dcr
  • .kdc
  • .erf
  • .mef
  • .mrw
  • .nef
  • .nrw
  • .orf
  • .raf
  • .raw
  • .rwl
  • .rw2
  • .r3d
  • .ptx
  • .pef
  • .srw
  • .x3f
  • .der
  • .cer
  • .crt
  • .pem
  • .pfx
  • .p12
  • .p7b
  • .p7c
  • .abw
  • .til
  • .aif
  • .arc
  • .as
  • .asc
  • .asf
  • .ashdisc
  • .asm
  • .asp
  • .aspx
  • .asx
  • .aup
  • .avi
  • .bbb
  • .bdb
  • .bibtex
  • .bkf
  • .bmp
  • .bpn
  • .btd
  • .bz2
  • .c
  • .cdi
  • .himmel
  • .cert
  • .cfm
  • .cgi
  • .cpio
  • .cpp
  • .csr
  • .cue
  • .dds
  • .dem
  • .dmg
  • .dsb
  • .eddx
  • .edoc
  • .eml
  • .emlx
  • .EPS
  • .epub
  • .fdf
  • .ffu
  • .flv
  • .gam
  • .gcode
  • .gho
  • .gpx
  • .gz
  • .h
  • .hbk
  • .hdd
  • .hds
  • .hpp
  • .ics
  • .idml
  • .iff
  • .img
  • .ipd
  • .iso
  • .isz
  • .iwa
  • .j2k
  • .jp2
  • .jpf
  • .jpm
  • .jpx
  • .jsp
  • .jspa
  • .jspx
  • .jst
  • .key
  • .keynote
  • .kml
  • .kmz
  • .lic
  • .lwp
  • .lzma
  • .M3U
  • .M4A
  • .m4v
  • .max
  • .mbox
  • .md2
  • .mdbackup
  • .mddata
  • .mdinfo
  • .mds
  • .mid
  • .mov
  • .mp3
  • .mp4
  • .mpa
  • .mpb
  • .mpeg
  • .mpg
  • .mpj
  • .mpp
  • .msg
  • .mso
  • .nba
  • .nbf
  • .nbi
  • .nbu
  • .nbz
  • .nco
  • .nes
  • .note
  • .nrg
  • .nri
  • .afsnit
  • .ogg
  • .ova
  • .ovf
  • .oxps
  • .p2i
  • .p65
  • .p7
  • .pages
  • .pct
  • .PEM
  • .phtm
  • .phtml
  • .php
  • .php3
  • .php4
  • .php5
  • .phps
  • .phpx
  • .phpxx
  • .pl
  • .plist
  • .pmd
  • .pmx
  • .ppdf
  • .pps
  • .ppsm
  • .ppsx
  • .ps
  • .PSD
  • .pspimage
  • .pvm
  • .qcn
  • .qcow
  • .qcow2
  • .qt
  • .ra
  • .rm
  • .rtf
  • .s
  • .sbf
  • .set
  • .skb
  • .slf
  • .sme
  • .smm
  • .spb
  • .sql
  • .srt
  • .ssc
  • .ssi
  • .stg
  • .stl
  • .svg
  • .swf
  • .sxw
  • .syncdb
  • .tager
  • .tc
  • .tex
  • .tga
  • .thm
  • .tif
  • .tiff
  • .toast
  • .torrent
  • .txt
  • .vbk
  • .vcard
  • .vcd
  • .vcf
  • .vdi
  • .vfs4
  • .vhd
  • .vhdx
  • .vmdk
  • .vob
  • .wbverify
  • .wav
  • .webm
  • .wmb
  • .wpb
  • .WPS
  • .xdw
  • .xlr
  • .XLSX
  • .xz
  • .yuv
  • .zipx
  • .jpg
  • .jpeg
  • .png
  • .bmp

It renames encrypted files using the following names:

  • {Original File Name}.encrypted.{Original File Extension}

It does the following:

  • Executes the following commands:
    • cmd.exe /c schtasks /create /sc onlogon /tn {Random number} /rl highest /tr %Program Files%\Common Files\{Malware Name}
    • cmd.exe /C title {Random Numbers}|vssadmin.exe Delete Shadows /All /Quiet
    • cmd.exe /C title {Random Numbers}|bcdedit /set {default} recoveryenabled No
    • cmd.exe /C title {Random Numbers}|bcdedit /set {default} bootstatuspolicy ignoreallfailures
  • Avoids encrypting %System Root%\Users\{Default|Defaultuser|Defaultuser0|Default User}
  • Encrypts files in the following:
    • All drives
    • Folders contains the string “AppData”
    • %Program Files%\Steam\steamapps\common
  • Also tries to encrypt files in locations found in the following registry:
    • HKCU64\Software\Microsoft\Windows\CurrentVersion\Explorer\PublishingWizard\AddNetworkPlace\AddNetPlace\LocationMRU
  • Requires the key "123" to decrypt the encrypted files
  • Display the following window:

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.308.06
FIRST VSAPI PATTERN DATE: 30 Mar 2017
VSAPI OPR PATTERN File: 13.309.00
VSAPI OPR PATTERN Date: 31 Mar 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete the Scheduled Tasks added by this malware/grayware

[ Learn More ]

To delete the added Scheduled Task file:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
  2. Double-click on a .JOB file.
  3. Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
  4. If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
  5. Repeat the steps above for the remaining .JOB files.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel of the Task Scheduler Window, click Task Scheduler Library.
  3. In the upper-middle panel, click a Task.
  4. In the lower middle panel, click the Actions tab
  5. Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
  6. If found, select the task and press DELETE and click Yes to delete the task.
  7. Repeat the steps above for the remaining tasks.

Step 5

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.  
  • %Program Files%\Common Files\{Malware Name}
  • %Program Files%\Common Files\{Random Numbers}
  • %Program Files%\Common Files\{Random Numbers}
  • %Program Files%\Common Files\log.txt

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CRYPTOWIRE.F117CU. 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 7

Restore encrypted files from backup.


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