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TROJ_DYNAMER.SZY

April 01, 2014
 ALIASES:

Trojan:Win32/Dynamer!ac (Microsoft); Trojan.Win32.Badur.hbfp (Kaspersky); Troj/AutoIt-ADU (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Autoit_c.AJIC (AVG)

 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:

1,626,668 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Apr 2014

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 creates the following folders:

  • %System Root%\ProgramData

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

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
Winfile.exe = "%System Root%\ProgramData\Winfile.exe"

It registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\explorer\
Browser Helper Objects\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}

HKEY_CLASSES_ROOT\CLSID\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}\
InprocServer32

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}\InprocServer32
ThreadingModel = "Apartment"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}
NoExplorer = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
EXT\CLSID
{77E4A958-E1BA-4242-A1F8-F6170E8673A1} = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_ENABLE_SCRIPT_PASTE_URLACTION_IF_PROMPT
iexplore.exe = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = "0"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\aut1.tmp
  • %System Root%\ProgramData\Winfile.exe
  • %System Root%\ProgramData\Update2014.cpl
  • %System Root%\ProgramData\IMG.jpg
  • %System Root%\ProgramData\gbpsvs.dll
  • %User Temp%\res.ico
  • %User Temp%\res.ico2

(Note: %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.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

Close all opened browser windows

Step 4

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_CLASSES_ROOT\CLSID
    • {77E4A958-E1BA-4242-A1F8-F6170E8673A1}
  • In HKEY_CLASSES_ROOT\CLSID\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}
    • InprocServer32

Step 5

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
    • Winfile.exe = "%System Root%\ProgramData\Winfile.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}\InprocServer32
    • ThreadingModel = "Apartment"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects\{77E4A958-E1BA-4242-A1F8-F6170E8673A1}
    • NoExplorer = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\EXT\CLSID
    • {77E4A958-E1BA-4242-A1F8-F6170E8673A1} = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_ENABLE_SCRIPT_PASTE_URLACTION_IF_PROMPT
    • iexplore.exe = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • EnableBalloonTips = "0"

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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 Temp%\aut1.tmp
  • %System Root%\ProgramData\Winfile.exe
  • %System Root%\ProgramData\Update2014.cpl
  • %System Root%\ProgramData\IMG.jpg
  • %System Root%\ProgramData\gbpsvs.dll
  • %User Temp%\res.ico
  • %User Temp%\res.ico2

Step 7

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.
  • %System Root%\ProgramData

Step 8

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