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TROJ_DYFUCA.I

October 13, 2012
 ALIASES:

Adware:Win32/Avenuemedia (Microsoft); Adware-DFC. (McAfee); Adware.NetOptimizer (Symantec); Trojan-Downloader.Win32.Dyfuca.cq (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan.Downloader.Dyfuca.CQ (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • 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:

84,224 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Jun 2012

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:

  • %Program Files%\Internet Optimizer\optimize.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It creates the following folders:

  • %Program Files%\Internet Optimizer

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Internet Optimizer = "%Program Files%\Internet Optimizer\optimize.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Avenue Media\
Internet Optimizer

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
DyFuCA

HKEY_CURRENT_USER\Software\Avenue Media

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
TargetDir = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
DisplayIcon = "%Program Files%\Internet Optimizer\optimize.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
DisplayName = "Internet Optimizer"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Internet Optimizer
UninstallString = "%Program Files%\Internet Optimizer\optimize.exe /u"

HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
CLS = "wsi6"

HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
RID = "c01"

HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\
Internet Optimizer
Version = "3.0.0"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://cdn.{BLOCKED}-etc.com/io/legal/EULA/EULA.ctxt

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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\Avenue Media
    • Internet Optimizer
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • Internet Optimizer
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • DyFuCA
  • In HKEY_CURRENT_USER\Software
    • Avenue Media

Step 4

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\CurrentVersion\Run
    • Internet Optimizer = "%Program Files%\Internet Optimizer\optimize.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
    • TargetDir = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Internet Optimizer
    • DisplayIcon = "%Program Files%\Internet Optimizer\optimize.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Internet Optimizer
    • DisplayName = "Internet Optimizer"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Internet Optimizer
    • UninstallString = "%Program Files%\Internet Optimizer\optimize.exe /u"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
    • CLS = "wsi6"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
    • RID = "c01"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Avenue Media\Internet Optimizer
    • Version = "3.0.0"

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.
  • %Program Files%\Internet Optimizer

Step 6

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