TSPY_URSNIF.YMNNF

This spyware 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 the initially executed copy of itself.

Arrival Details

This spyware 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 spyware drops and executes the following files:

• %User Temp%\{random folder name}\{random filename}.bat ← used to execute copy and delete itself

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

• %Application Data%\{string1}{string2}\{string1}{string2}.exe
  where:
  {string1} = first four letters of a dll file under %System% directory
  {string2} = last four letters of a dll file under %System% directory

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

It creates the following folders:

• %Application Data%\{string1}{string2}
  where:
  {string1} = first four letters of a dll file under %System% directory
  {string2} = last four letters of a dll file under %System% directory

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

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{string1}{string2} = %Application Data%\{string1}{string2}\{string1}{string2}.exe

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Vars

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Files

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}\
Config

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"

HKEY_CURRENT_USER\Software\AppDataLow\
Software\Microsoft\{GUID}
{Value Name} = "{hex value}"
where {Value Name} may be any of the following:

• Main
• Block
• Temp
• Client
• Ini
• Keys
• Scr
• Install
• LastTask
• LastConfig
• CrHook
• OpHook
• Exec
• NetCfg
• LastIni

Dropping Routine

This spyware drops the following files wherein it saves the information it gathers:

• %User Temp%\{random filename}.bin

(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.)

Other Details

This spyware connects to the following possibly malicious URL:

• http://{domain}/images/{random path}.{bmp/gif/jpeg}
  where {domain} can be any of the following:
  • {BLOCKED}unw10.com
  • {BLOCKED}nd.com
  • {BLOCKED}ee.com
  • {BLOCKED}oo.com
  • {BLOCKED}nw.com
  
  

It deletes the initially executed copy of itself