Analysis by: kathleenno

ALIASES:

Trojan.Gen (Symantec); Trojan:Win32/Agent.OO (Microsoft); Packed.Win32.PePatch.ju (Kaspersky); Generic Malware.ek (Mcafee); Mal/Behav-204 (Sophos)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • 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.

It drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 19,456 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 May 2011

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.

Installation

This worm drops the following files:

  • %User Temp%\rs.bat
  • %System%\svchost.ini

(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.. %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 drops the following copies of itself into the affected system:

  • %System%\drivers\svchost.exe
  • %System Root%\{random filename}.exe
  • %Program Files%\Common Files\{random filename}.exe
  • %Program Files%\Internet Explorer\Connection Wizard\{random filename}.exe
  • %Program Files%\Windows Media Player\{random filename}.exe
  • %Windows%\addins\{random filename}.exe
  • %Windows%\system\{random filename}.exe
  • %System%\dllcache\{random filename}.exe
  • %System%\IME\{random filename}.exe

(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.. %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.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
ImagePath = "%System%\drivers\svchost.exe"

(Note: The default value data of the said registry entry is %Systemroot%\system32\svchost.exe -k netsvcs.)

Other System Modifications

This worm modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
Type = "110"

(Note: The default value data of the said registry entry is 20.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
ErrorControl = "0"

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv
Description = "??????? Windows ???????????,???????? Windows Update ????????"

(Note: The default value data of the said registry entry is Enables the download and installation of Windows updates. If this service is disabled, this computer will not be able to use the Automatic Updates feature or the Windows Update Web site..)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wuauserv\Parameters

Propagation

This worm drops copies of itself in all removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[AutoRun]
open=setup.exe
shellexecute=setup.exe
shell\Auto\command=setup.exe

Other Details

This worm deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: currently processing

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

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\CurrentControlSet\Services\wuauserv
    • From: ImagePath = "%System%\drivers\svchost.exe"
      To: ImagePath = "%Systemroot%\system32\svchost.exe -k netsvcs"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv
    • From: Type = "110"
      To: Type = "20"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv
    • From: ErrorControl = "0"
      To: ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv
    • From: Description = "??????? Windows ???????????,???????? Windows Update ????????"
      To: Description = "Enables the download and installation of Windows updates. If this service is disabled, this computer will not be able to use the Automatic Updates feature or the Windows Update Web site."

Step 4

Search and delete this file

[ 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 Temp%\rs.bat
%System%\svchost.ini

Step 5

Search and delete AUTORUN.INF files created by WORM_HUPIGO.FT that contain these strings

[ Learn More ]
[AutoRun]
open=setup.exe
shellexecute=setup.exe
shell\Auto\command=setup.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_HUPIGO.FT. 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 deleted registry key/value 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.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv\Parameters


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