RANSOM_CRYPVAULT.A

This Trojan may arrive bundled with malware packages as a malware component. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

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 Trojan drops a copy of itself in the following folders using different file names:

• %System%\{name of legitimate application}\{name of legitimate application}.{random extension} - set to hidden

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following file(s)/component(s):

• %Application Data%\VAULT.hta
• %Application Data%\Microsoft\Windows\Templates\VAULT.hta
• {drive}\VAULT.hta
• %System Root%\VAULT.hta
• %User Startup%\VAULT.hta
• %Desktop%\VAULT.hta
• %Application Data%\VAULT.KEY
• %Application Data%\Microsoft\Windows\Templates\VAULT.KEY
• %Desktop%\VAULT.KEY
• {drive}\VAULT.hta
• %System Root%\VAULT.KEY
• %Application Data%\CONFIRMATION.KEY
• %Application Data%\Microsoft\Windows\Templates\CONFIRMATION.KEY

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.. %Desktop% is the desktop folder, where it usually is C:\Documents and Settings\{user name}\Desktop in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\Desktop in 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 codes into the following process(es):

• explorer.exe
• svchost.exe

Autostart Technique

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

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{name of legitimate application} = %System%\{name of legitimate application}\{name of legitimate application}.{random extension}

File Infection

This Trojan avoids infecting files that contain the following strings in their names:

• windows
• temp
• recycle
• program
• appdata
• avatar
• roaming
• msoffice
• temporary
• sample
• themes
• uploads
• csize
• resource
• internet
• com_
• intel
• common
• resources
• texture
• profiles
• library
• clipart
• manual
• games
• framework64
• setupcache
• autograph
• maps
• amd64
• cache
• support
• guide
• abbyy
• application
• thumbnails
• avatars
• template
• adobe

Download Routine

This Trojan connects to the following URL(s) to download its component file(s):

• {BLOCKED}comingsoon.com

Other Details

This Trojan encrypts files with the following extensions:

• *.xls
• *.doc
• *.pdf
• *.rtf
• *.psd
• *.dwg
• *.cdr
• *.cd
• *.mbd
• *.1cd
• *.dbf
• *.sqlite
• *.jpg
• *.zip
• *.7z

It renames encrypted files using the following names:

• {file name and extension}.vault

It deletes itself after execution.

NOTES:

The file VAULT.HTA is the ransom note.