TROJ_ALUREON.DSO

 Analysis by: Christopher Daniel So

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


This Trojan arrives as a file that exports the functions of other malware/grayware. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It opens a hidden Internet Explorer window.

  TECHNICAL DETAILS

File Size:

196,624 bytes

File Type:

PE

Initial Samples Received Date:

29 Jan 2011

Payload:

Patches files

Arrival Details

This Trojan arrives as a file that exports the functions of other malware/grayware.

It 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:

  • %System%\{random file name}.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It injects itself into the following processes running in the affected system's memory:

  • explorer.exe

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random service name}
ImagePath = "%System Root%\System32\svchost.exe -k netsvcs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random service name}\Parameters
ServiceDll = "{malware path and file name}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random service name}
DisplayName = "{random service name} System Services"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{malware file name} = "Rundll32.exe {malware path and file name},Rundll32Main"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

Download Routine

This Trojan connects to the following malicious URLs:

  • http://www.{BLOCKED}ver.com/xcip.asp

Other Details

This Trojan opens a hidden Internet Explorer window.

It does the following:

  • Selects a. DLL in the Windows system folder and copies it at %System%\{file name}.dll.obak. It then overwrites %System%\{file name}.dll with a copy of itself.
  • Copies the file %System%\conime.exe as %System%\eminoc_bd.dll, and the file %System%\spoolsv.exe as %System%\vsloops_bd.dll. It then patches the files %System%\conime.exe and %System%\spoolsv.exe with code that automatically loasd this Trojan when the patched files are executed. Trend Micro detects the patched files are detected as PTCH_ALUREON.DSO.

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

7.800.03

FIRST VSAPI PATTERN DATE:

29 Jan 2011

VSAPI OPR PATTERN File:

7.801.00

VSAPI OPR PATTERN Date:

29 Jan 2011

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

Remove malware files dropped/downloaded by TROJ_ALUREON.DSO

    • PTCH_ALUREON.DSO

Step 3

Scan your computer with your Trend Micro product and note files detected as TROJ_ALUREON.DSO

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the file detected as TROJ_ALUREON.DSO

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

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\CurrentVersion\Run
    • {malware file name} = Rundll32.exe {malware path and file name},Rundll32Main

Step 7

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\SYSTEM\CurrentControlSet\Services
    • {random service name}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
    • msvideo

Step 8

Restoring a File to its Original Location

  1. Click Start>Run.
  2. In the text box, type the following:
    command /c copy %System%\eminoc_bd.dll %System%\conime.exe
    command /c copy %System%\vsloops_bd.dll %System%\spoolsv.exe
    command /c copy %System%\{file name}.dll.obak %System%\{file name}.dll
  3. Press Enter.

Step 9

Search and delete these files

[ Learn More ]
There may be some component 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%\eminoc_bd.dll
  • %System%\vsloops_bd.dll
  • %System%\{file name}.dll.obak

Step 10

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