ALIASES:

Trojan.Spuler (Symantec)

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 107,907 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 26 Nov 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.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSFix

HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003\Software\
Microsoft\Internet Explorer\Main\
FeatureControl\FEATURE_LOCALMACHINE_LOCKDOWN

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
MSFix
icnosltoarll = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_LOCALMACHINE_LOCKDOWN
iexplore.exe = "0"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\HTTPFilter
Start = "2"

(Note: The default value data of the said registry entry is 3.)

It deletes the following registry keys:

HKEY_USERS\.DEFAULT\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-19\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-19_Classes\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-20\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-20_Classes\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003_Classes\SOFTWARE\
Microsoft\MSFix

HKEY_USERS\S-1-5-18\SOFTWARE\
Microsoft\MSFix

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Network\a
  • %Temp%\d091.tmp
  • %User Temp%\Start.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.. %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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}awn.com/components/com_poll/models/polls.php?{random characters}
  • http://{BLOCKED}vecchiainforma.it/cms/components/com_poll/images/polls.php?{random characters}

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

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\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003\Software\Microsoft\Internet Explorer\Main\FeatureControl
    • FEATURE_LOCALMACHINE_LOCKDOWN

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_LOCAL_MACHINE\SOFTWARE\Microsoft\MSFix
    • icnosltoarll = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_LOCALMACHINE_LOCKDOWN
    • iexplore.exe = "0"

Step 4

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\SYSTEM\ControlSet001\Services\HTTPFilter
    • From: Start = "2"
      To: Start = ""3""

Step 5

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.
  • %User Profile%\Network\a
  • %Temp%\d091.tmp
  • %User Temp%\Start.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADR.YQ. 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.

Step 7

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_USERS\.DEFAULT\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-19\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-19_Classes\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-20\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-20_Classes\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-21-1645522239-1292428093-682003330-1003_Classes\SOFTWARE\Microsoft
    • MSFix
  • In HKEY_USERS\S-1-5-18\SOFTWARE\Microsoft
    • MSFix


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