TROJ_VUNDO.FZX

 Analysis by: Maydalene Edsel Salvador

 ALIASES:

TrojanDropper:Win32/Vundo.AA (Microsoft), RDN/Downloader.a!df (NAI), TR/Kazy.408.54 (AntiVir), Trojan.Vundo.HAF (BitDefender), W32/Cidox.AE!tr.bdr (Fortinet), Trj/OCJ.D (Panda)

 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:
 SYSTEM IMPACT RATING:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

File Size:

144,384 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Apr 2013

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 files:

  • %User Profile%\My Documents\Iterra\0105.tmp
  • %User Profile%\My Documents\Iterra\T03emp03.reg
  • %System%\{7_RANDOMCHAR}.dll
  • %User Profile%\Cookies\cf

(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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It creates the following folders:

  • %User Profile%\My Documents\Iterra

(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.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
LoadAppInit_DLLs = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Windows
AppInit_DLLs = "%System%\werksdg.dll"

(Note: The default value data of the said registry entry is "".)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}ad.com
  • {BLOCKED}ns.com
  • {BLOCKED}ip.com
  • {BLOCKED}ip.com
  • {BLOCKED}ast.com
  • {BLOCKED}1etag.com
  • {BLOCKED}all.com
  • {BLOCKED}nda.com
  • {BLOCKED}nma.com
  • {BLOCKED}mva.com
  • {BLOCKED}ix.com
  • {BLOCKED}od.com
  • {BLOCKED}rns.com
  • {BLOCKED}it.com
  • {BLOCKED}ets.com
  • {BLOCKED}su.com
  • {BLOCKED}ck.com
  • {BLOCKED}ra.com
  • {BLOCKED}lans.ru
  • {BLOCKED}e1.com
  • {BLOCKED}eta.ru
  • {BLOCKED}click.com
  • {BLOCKED}tano.com

NOTES:

After T03emp03.reg is installed in the registry, it deletes the following folders and files:

  • %User Profile%\My Documents\Iterra
  • %User Profile%\My Documents\Iterra\0105.tmp
  • %User Profile%\My Documents\Iterra\T03emp03.reg

  SOLUTION

Minimum Scan Engine:

9.300

VSAPI OPR PATTERN File:

9.850.06

VSAPI OPR PATTERN Date:

27 Feb 2013

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

Scan your computer with your Trend Micro product and note files detected as TROJ_VUNDO.FZX

Step 3

Restart in Safe Mode

[ Learn More ]

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.
  • %System%\{7_RANDOMCHAR}.dll
  • %User Profile%\Cookies\cf

Step 5

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\My Documents\Iterra

Step 6

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • LoadAppInit_DLLs = "1"

Step 7

Restore this modified 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows
    • From: AppInit_DLLs = "%System%\werksdg.dll"
      To: AppInit_DLLs = ""

Step 8

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