RANSOM_SPORA.K

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.

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 copies of itself into the affected system:

• %Desktop%\{random values}.exe (set as hidden)
• {all removable and fixed drives}\{random values}.exe (set as hidden)

(Note: %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 drops the following files:

• %Desktop%\{Shortcut files with the filename of every folder in the desktop}
• %User Startup%\{unique id}.HTML (ransom note, to enable automatic execution at system startup)
• %AppDataLocal%\VirtualStore\{unique id}.html
• {fixed drive letter}\{unique id}.html
• %Application Data%\{unique id}
• {Fixed and Removable Drive Letter}:\{Shortcut files with the filename of every folder in the removable and fixed drive}
  • The malware creates these shortcut files in order to trick the user due to its folder icon and legit filenames.
  • The target path of these shortcuts is set to: %SYSTEM%\cmd.exe /c explorer.exe "{target folder name}" & type "{random values - malware copy}.exe" > "{random values - malware copy}.exe" && "%temp%\{random values - malware copy}.exe"
  • The affected folders are set to HIDDEN.
• %Application Data%\{10 digit number}

(Note: %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.. %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.. %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.. %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.)

It drops and executes the following files:

• %Application Data%\{unique id}.HTML (Ransom Note)

(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.)

Other System Modifications

This Trojan deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
lnkfile
IsShortcut = ""

Other Details

This Trojan encrypts files with the following extensions:

• .1cd
• .7z
• .accdb
• .backup
• .cd
• .cdr
• .dbf
• .doc
• .docx
• .dwg
• .jpeg
• .jpg
• .mdb
• .odt
• .pdf
• .psd
• .rar
• .rtf
• .sqlite
• .tiff
• .xls
• .xlsx
• .zip

It does the following:

• This ransomware deletes all shadow copies by executing the following command:
  vssadmin delete shadows /all /quiet
• It prevents encrypting files containing any of the strings in its full path name:
  • games
  • program files (x86)
  • program files
  • windows

NOTES:

This ransomware displays the following images: