RANSOM_WCRY.C
Windows
Threat Type: Ransomware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This Ransomware arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It 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 file(s)/component(s):
- {location of malware}\00000000.pky
- {location of malware}\00000000.eky
- {location of malware}\00000000.res
- {location of malware}\!Please Read Me!.txt ← ransomnote
- {location of malware}\{random numbers}.bat ← creates shortcut
- {location of malware}\!WannaDecryptor!.exe.lnk
- {location of malware}\TaskHost\Tor\taskhosts.exe ← copy of tor.exe
- {location of malware}\t.wry ← encrypted component
- {location of malware}\c.wry ← contains email, bitcoin address, onion server, & urls
- {location of malware}\r.wry ← ransomnote
- {location of malware}\m.wry ← rtf file containing ransom instructions
- {location of malware}\f.wry ← encrypted files
- {location of malware}\b.wry ← bmp file used for desktop
- {location of malware}\u.wry ← tool detected as RANSOM_WCRY.C
- {location of malware}\!WannaDecryptor!.exe ← tool also detected as RANSOM_WCRY.C
- {location of malware}\!WannaDecryptor!.bmp ← ransom wallpaper
It adds the following processes:
- taskhosts.exe
It creates the following folders:
- {location of malware}\TaskHost
Autostart Technique
This Ransomware adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft Task Scheduler = "{location of malware}\{malware filename}.exe" /r 0
Other System Modifications
This Ransomware adds the following registry keys:
HKLM\SOFTWARE\WannaCryptor
HKCU\SOFTWARE\WannaCryptor
It changes the desktop wallpaper by modifying the following registry entries:
HKCU\Control Panel\Desktop
Wallpaper = "{location of malware}\!WannaDecryptor!.bmp"
It sets the system's desktop wallpaper to the following image:
Download Routine
This Ransomware accesses the following websites to download files:
- https://dist.{BLOCKED}ject.org/torbrowser/6.5.1/tor-win32-0.2.9.10.zip
- https://www.dropbox.com/s/{BLOCKED}erh1ks/m.rar?dl=1 - hosts - !WannaDecryptor!.exe, detected as RANSOM_WCRY.C
- https://www.dropbox.com/s/{BLOCKED}zazlyy94/t.zip?dl=1 - hosts Tor archive
Other Details
This Ransomware encrypts files with the following extensions:
- .123
- .3dm
- .3ds
- .3g2
- .3gp
- .602
- .7z
- .aes
- .ai
- .ARC
- .asc
- .asf
- .asp
- .avi
- .backup
- .bak
- .bmp
- .brd
- .bz2
- .c
- .cgm
- .class
- .cpp
- .crt
- .cs
- .csr
- .csv
- .db
- .dbf
- .dch
- .dif
- .dip
- .doc
- .docb
- .docm
- .docx
- .dot
- .dotm
- .dotx
- .dwg
- .edb
- .eml
- .fla
- .flv
- .frm
- .gif
- .gpg
- .gz
- .h
- .hwp
- .ibd
- .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
- .ost
- .otg
- .otp
- .ots
- .ott
- .p12
- .PAQ
- .pas
- .pem
- .php
- .pl
- .png
- .pot
- .potm
- .potx
- .ppam
- .pps
- .ppsm
- .ppsx
- .ppt
- .pptm
- .pptx
- .psd
- .pst
- .rar
- .raw
- .rb
- .rtf
- .sch
- .sh
- .slk
- .sln
- .sql
- .sqlite3
- .sqlitedb
- .stc
- .std
- .stw
- .suo
- .swf
- .sxc
- .sxd
- .sxm
- .sxw
- .tar
- .tar
- .tbk
- .tgz
- .tif
- .tiff
- .txt
- .uop
- .uot
- .vb
- .vdi
- .vmdk
- .vmx
- .vob
- .vsd
- .vsdx
- .wav
- .wb2
- .wk1
- .wks
- .wma
- .wmv
- .xlc
- .xlm
- .xls
- .xlsb
- .xlsm
- .xlsx
- .xlt
- .xltm
- .xltx
- .xlw
- .zip
It renames encrypted files using the following names:
- {original filename and extension}.WCRY
It does the following:
- Displays the following:
- !WannaDecryptor!.exe - used for bitcoin payments, ransom intructions and timer, it depends on other components
- {random numbers}.bat - creates, executes and deletes c.vbs, a script file that creates !WannaDecryptor!.exe.lnk
- It disables or turns off Windows Error Recovery Screen on Startup using the following command:
- bcdedit /set {default} bootstatuspolicy ignoreallfailures
- It disables Startup Repair from running using the following command:
- bcdedit /set {default} recoveryenabled no
- It deletes the backup catalog using the following command:
- wbadmin delete catalog -quiet
- This ransomware extracts the downloaded zip file in the {location of malware}\TaskHost folder.
- The downloaded zip file contains the following files:
- Data\Tor\geoip
- Data\Tor\geoip6
- Tor\libeay32.dll
- Tor\libevent-2-0-5.dll
- Tor\libevent_core-2-0-5.dll
- Tor\libevent_extra-2-0-5.dll
- Tor\libgcc_s_sjlj-1.dll
- Tor\libssp-0.dll
- Tor\ssleay32.dll
- Tor\tor.exe
- Tor\zlib1.dll
- This ransomware deletes shadow copies by executing the following command:
- vssadmin delete shadows /all /quiet
- wmic shadowcopy delete
- This ransomware avoids encrypting file with the following strings in their file path:
- AppData
- \Users\
- \ProgramData
- \Program Files (x86)
- \Program Files
- \Windows
SOLUTION
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
Step 4
Delete this registry value
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\Microsoft\Windows\CurrentVersion\Run
- Microsoft Task Scheduler = "{location of malware}\{malware filename}.exe" /r 0
- Microsoft Task Scheduler = "{location of malware}\{malware filename}.exe" /r 0
Step 5
Delete this registry key
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
- WannaCryptor = ""
- WannaCryptor = ""
- In HKEY_CURRENT_USER\SOFTWARE
- WannaCryptor = ""
- WannaCryptor = ""
Step 6
Search and delete these folders
- {location of malware}\TaskHost
Step 7
Search and delete these files
- {location of malware}\00000000.pky
- {location of malware}\00000000.eky
- {location of malware}\00000000.res
- {location of malware}\!Please Read Me!.txt
- {location of malware}\{random numbers}.bat
- {location of malware}\!WannaDecryptor!.exe.lnk
- {location of malware}\TaskHost\Tor\taskhosts.exe
- {location of malware}\t.wry
- {location of malware}\c.wry
- {location of malware}\r.wry
- {location of malware}\m.wry
- {location of malware}\f.wry
- {location of malware}\b.wry
- {location of malware}\!WannaDecryptor!.bmp
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_WCRY.C. 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 9
Reset your Desktop properties
Step 10
Restore encrypted files from backup.
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