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TROJ_SIREFEF.BCC

September 16, 2013
 Analysis by: Joie Salvio
 ALIASES:

TrojanDropper:Win32/Sirefef.BB (Microsoft), Win32/Sirefef.FY trojan (ESET)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This Trojan deletes itself after execution.

  TECHNICAL DETAILS

File Size:

265,728 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Sep 2013

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\GoogleUpdate.exe
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\GoogleUpdate.exe

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It drops the following files:

  • %Windows%\assembly\GAC\Desktop.ini
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\@
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\@

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It creates the following folders:

  • %AppDataLocal%\Google\Desktop\Install\{GUID}
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\U
  • %AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\L
  • %Program Files%\Google\Desktop\Install\{GUID}
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\U
  • %Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\L

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

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
Google Update = ""%AppDataLocal%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\GoogleUpdate.exe" >"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{unprintable character}etadpug
Parameters = "136"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{unprintable character}etadpug
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{unprintable character}etadpug
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{unprintable character}etadpug
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{unprintable character}etadpug
ImagePath = "%Program Files%\Google\Desktop\Install\{GUID}\{unprintable characters1}\{unprintable characters2}\{unprintable characters3}\{GUID}\GoogleUpdate.exe"

It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\{unprintable character}etadpug

Other System Modifications

This Trojan deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_BITS

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_SHAREDACCESS

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WSCSVC

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_WUAUSERV

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\BITS

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://j.{BLOCKED}d.com/app/geoip.js

It deletes itself after execution.