This cryptoransomware variant was discovered to be involved in a series of malicious campaigns that found victims in Europe, China, Middle East, Africa, India, and Latin America on late January 2015. It encrypts files using various file extensions. Users affected by this malware may find their important documents or files unable to be used and/or accessed.
To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.
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.
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:
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.txt - copy of the ransom note
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.bmp - copy of the .bmp file
- %User Profile%\My Documents\Decrypt All Files {random characters}.bmp - image used as wallpaper
- %User Profile%\My Documents\Decrypt All Files {random characters}.txt - ransom note in text file
- %All Users Profile%\Application Data\{random characters}.html - contains ransom note and list of encrypted files
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It drops the following copies of itself into the affected system:
- %User Temp%\{random filename}.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It injects itself into the following processes running in the affected system's memory:
It creates the following folders:
- %All Users Profile%\Application Data\{randomly selected path}\{random characters}
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Trojan drops the following files:
- C:\Windows\Tasks\{random filename}.job
Other System Modifications
This Trojan modifies the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
Wallpaper = "%User Profile%\My Documents\Decrypt All Files {random characters}.bmp"
(Note: The default value data of the said registry entry is {user-defined}.)
HKEY_CURRENT_USER\Control Panel\Desktop
TileWallpaper = 0
Other Details
This Trojan connects to the following website to send and receive information:
- {BLOCKED}jrzduo52siy.onion.cab
- {BLOCKED}jrzduo52siy.tor2web.org
- {BLOCKED}jrzduo52siy.onion.gq
- {BLOCKED}jrzduo52siy.tor2web.fi
- {BLOCKED}jrzduo52siy.onion.lt
- {BLOCKED}jrzduo52siy.tor2web.blutmagie.de
It encrypts files with the following extensions:
- 3fr
- 7z
- acc
- ai
- arw
- bas
- bay
- bl
- c
- cdr
- cer
- cpp
- cr2
- crt
- crw
- cs
- db
- dbf
- dcr
- dd
- dds
- der
- dng
- doc
- docm
- docx
- dwg
- dxf
- dxg
- end
- eps
- erf
- groups
- indd
- jpe
- jpeg
- jpg
- js
- kdc
- kwm
- md
- mdb
- mdf
- mef
- mrw
- nef
- nrw
- odb
- odm
- odp
- ods
- odt
- orf
- p12
- p7b
- p7c
- pas
- pdd
- pdf
- pef
- pem
- pfx
- php
- pl
- ppt
- pptm
- pptx
- psd
- pst
- ptx
- pwm
- py
- r3d
- raf
- rar
- raw
- rtf
- rw2
- rwl
- safe
- sql
- srf
- srw
- txt
- vsd
- wb2
- wpd
- wps
- xlk
- xls
- xlsb
- xlsm
- xlsx
- zip
- blend
- dbx
- gdb
- bsdr
- bsdu
- bdcr
- bdcu
- bpdr
- bpdu
- ims
- bds
- bdd
- bdp
- gsf
- gsd
- iss
- arp
- rik
- fdb
- abu
- fig
- con
- rgx
NOTES:
This malware deletes all Windows Shadow Copies found in the system.
The dropped Decrypt All Files {random characters}.txt contains the following ransom message:
It sets the system's desktop wallpaper to the following image:
It appends the extension .{seven random characters} to the encrypted files. (ex. sample.docx.{seven random characters})
It displays the ransom message in four different languages: German, Dutch, Italian and English
It can decrypt five random files to entice the user that it is capable of recovering the files after payment of ransom.
If the connection to the server is established, it will save the details of the private key in %Application Data%\{randomly selected path}\{random file name}.
It will then asks the user to pay the ransom in bitcoin to automatically decrypt the files. It also contain instructions how to buy bitcoins via cash, electronic currency and etc.
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
Scan your computer with your Trend Micro product and note files detected as TROJ_CRYPCTB.SME
Step 4
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista, Windows 7, and Windows Server 2008 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
Step 5
Search and delete this file
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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 Profile%\My Documents\Decrypt All Files {random characters}.bmp
- %User Profile%\My Documents\Decrypt All Files {random characters}.txt
- %User Profile%\My Documents\{random characters}.html
- %Windows%\Tasks\{random filename}.job
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.txt
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.bmp
To manually delete a malware/grayware file from an affected system:
• For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the File name* input box, type the following:
- %User Profile%\My Documents\Decrypt All Files {random characters}.bmp
- %User Profile%\My Documents\Decrypt All Files {random characters}.txt
- %User Profile%\My Documents\{random characters}.html
- %Windows%\Tasks\{random filename}.job
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.txt
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.bmp
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: The file name input box title varies depending on the Windows version (e.g. Search for files or folders named or All or part of the file name.).
• For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open a Windows Explorer window.
- For Windows Vista, 7, and Server 2008 users, click Start>Computer.
- For Windows 8, 8.1, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
- In the Search Computer/This PC input box, type:
- %User Profile%\My Documents\Decrypt All Files {random characters}.bmp
- %User Profile%\My Documents\Decrypt All Files {random characters}.txt
- %User Profile%\My Documents\{random characters}.html
- %Windows%\Tasks\{random filename}.job
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.txt
- %System Root%\{randomly selected path}\Decrypt All Files {random characters}.bmp
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 6
Restore these modified registry values
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Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Control Panel\Desktop
- From: Wallpaper = "%User Profile%\My Documents\Decrypt All Files {random characters}.bmp"
To: Wallpaper = "{user-defined}"
To restore registry values this malware/grayware modified:
- Open Registry Editor. To do this:
- On Windows 2000, XP, and Server 2003:
Click Start>Run, type REGEDIT in the text box provided, and then press Enter. - On Windows Vista, 7, and Server 2008:
Click the Start button, type REGEDIT in the Search input field then press Enter. - On Windows 8, 8.1, and Server 2012:
Right-click on the lower left corner of the screen and click Run, type REGEDIT in the Run input field, and then press Enter.
- In the left panel, double-click the following:
HKEY_CURRENT_USER>Control Panel>Desktop - In the right panel, locate the registry value:
Wallpaper = "%User Profile%\My Documents\Decrypt All Files {random characters}.bmp" - Right-click on the value name and choose Modify. Change the value data of this entry to:
Wallpaper = "{user-defined}" - Close Registry Editor.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPCTB.SME. 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.
NOTES:
Restore the encrypted files from backup.
