BKDR_TOFSEE.JV

July 14, 2014
 Analysis by: RonJay Kristoffer Caragay
 ALIASES:

Backdoor.Win32.Tofsee.eh(Kaspersky), TR/Dropper.Gen(Antivir), Trojan horse Inject2.ANCA(AVG)

 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: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor 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.

  TECHNICAL DETAILS

File Size:

45,195,264 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Jul 2014

Arrival Details

This backdoor 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 backdoor drops and executes the following files:

  • %User Profile%\{random}.exe
  • %User Temp%\{random number}.bat <-deleted afterwards

(Note: %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.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
MSConfig = "%User Profile%\{random}.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DeviceControl
DevData0 = "{hex values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DeviceControl
DevData1 = "{hex values}"

Other Details

This backdoor deletes itself after execution.

NOTES:
This Trojan connects to the following non-malicious URL:

  • trendnet.org
  • google.com
  • yahoodns.net
  • hotmail.com
  • mx.aol.com
  • xerox.com
  • crowncars.com
  • globo.com
  • microsoft.com
  • yahoo.com
  • mail.ru

  SOLUTION

Minimum Scan Engine:

9.700

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • MSConfig = "%User Profile%\{random}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DeviceControl
    • DevData0 = "{hex values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DeviceControl
    • DevData1 = "{hex values}"

Step 4

Search and delete this file

[ Learn More ]
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%\{random}.exe
  • %User Temp%\{random number}.bat

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_TOFSEE.JV. 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.


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