ALIASES:

Trojan:Win32/VB.AAK (Microsoft); Generic.dx!zh (McAfee); Trojan.ADH (Symantec); Trojan.Win32.VB.uat (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan horse Dropper.Generic.ATCF (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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: 110,592 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 07 Jun 2013

Arrival Details

This worm 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 worm deletes the following files:

  • %Program Files%\Intern~1\IEXPLORES.EXE
  • %User Temp%\tmp.exe
  • %Program Files%\Intern~1\IEXPLORERSS.BAK
  • %Program Files%\Intern~1\IEXPLORERS.EXE
  • %Program Files%\Intern~1\IEXPLORESX.EXE
  • %User Temp%\1306061934.tmp
  • %User Temp%\1306061933.tmp
  • %User Temp%\1306061932.tmp
  • %User Temp%\1306061931.tmp
  • %User Temp%\1306061930.tmp
  • %User Temp%\1306061929.tmp
  • %User Temp%\1306061928.tmp
  • %User Temp%\1306061927.tmp
  • %User Temp%\1306061926.tmp
  • %User Temp%\1306061925.tmp
  • %User Temp%\1306061924.tmp
  • %User Temp%\1306061923.tmp
  • %User Temp%\1306061922.tmp
  • %User Temp%\1306061921.tmp
  • %User Temp%\1306061920.tmp
  • %User Temp%\1306061919.tmp
  • %User Temp%\1306061918.tmp
  • %User Temp%\1306061917.tmp
  • %User Temp%\1306061916.tmp
  • %User Temp%\1306061915.tmp
  • %User Temp%\1306061914.tmp
  • %User Temp%\1306061913.tmp
  • %User Temp%\1306061912.tmp
  • %User Temp%\1306061911.tmp
  • %User Temp%\1306061910.tmp
  • %User Temp%\1306061909.tmp
  • %User Temp%\1306061908.tmp
  • %User Temp%\1306061907.tmp
  • %User Temp%\1306061906.tmp
  • %Temp%\scsA.tmp
  • %Temp%\scsD.tmp

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %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.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\tydown

It adds the following registry entries:

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

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
Checkedvalue = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 1.)

Dropping Routine

This worm drops the following files:

  • %User Temp%\1306061936.exe
  • %User Temp%\1306061936.tmp
  • %System Root%\Documents and Settings.exe
  • %Program Files%.exe
  • %Windows%.exe

(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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).. %Windows% is the Windows folder, which is usually C:\Windows.)

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

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_CURRENT_USER\Software\Microsoft\Windows
    • tydown

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • ShowSuperHidden = "0"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: Checkedvalue = "0"
      To: Checkedvalue = ""1""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = ""2""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = ""1""

Step 5

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%\1306061936.exe
  • %User Temp%\1306061936.tmp
  • %System Root%\Documents and Settings.exe
  • %Program Files%.exe
  • %Windows%.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_SOHANAD.SU. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Program Files%\Intern~1\IEXPLORES.EXE
  • %User Temp%\tmp.exe
  • %Program Files%\Intern~1\IEXPLORERSS.BAK
  • %Program Files%\Intern~1\IEXPLORERS.EXE
  • %Program Files%\Intern~1\IEXPLORESX.EXE
  • %User Temp%\1306061934.tmp
  • %User Temp%\1306061933.tmp
  • %User Temp%\1306061932.tmp
  • %User Temp%\1306061931.tmp
  • %User Temp%\1306061930.tmp
  • %User Temp%\1306061929.tmp
  • %User Temp%\1306061928.tmp
  • %User Temp%\1306061927.tmp
  • %User Temp%\1306061926.tmp
  • %User Temp%\1306061925.tmp
  • %User Temp%\1306061924.tmp
  • %User Temp%\1306061923.tmp
  • %User Temp%\1306061922.tmp
  • %User Temp%\1306061921.tmp
  • %User Temp%\1306061920.tmp
  • %User Temp%\1306061919.tmp
  • %User Temp%\1306061918.tmp
  • %User Temp%\1306061917.tmp
  • %User Temp%\1306061916.tmp
  • %User Temp%\1306061915.tmp
  • %User Temp%\1306061914.tmp
  • %User Temp%\1306061913.tmp
  • %User Temp%\1306061912.tmp
  • %User Temp%\1306061911.tmp
  • %User Temp%\1306061910.tmp
  • %User Temp%\1306061909.tmp
  • %User Temp%\1306061908.tmp
  • %User Temp%\1306061907.tmp
  • %User Temp%\1306061906.tmp
  • %Temp%\scsA.tmp
  • %Temp%\scsD.tmp


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