Analysis by: Mar Philip Elaurza

ALIASES:

Worm:Win32/Taterf.B (Microsoft); Trojan-GameThief.Win32.Magania.bset (Kaspersky); W32.Gammima.AG (Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via removable drives, Downloaded from the Internet

This worm arrives by connecting affected removable drives to a system. 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 drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It does not have any backdoor routine.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

It steals sensitive information such as user names and passwords, particularly for certain games. Stolen information may be used for profit by cybercriminals who may gain access to the information.

It creates an event. However, as of this writing, the said sites are inaccessible. It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 94,208 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 06 Mar 2011
Payload: Downloads files, Steals information

Arrival Details

This worm arrives by connecting affected removable drives to a system.

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 worm drops and executes the following files:

  • %System%\ahnxsds0.dll
  • %System%\ahnfgss0.dll

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %System%\ahnsbsb.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following processes:

  • iexplore.exe

It injects itself into the following processes as part of its memory residency routine:

  • explorer.exe
  • created iexplore.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ahnsoft = "%System%\ahnsbsb.exe"

Other System Modifications

This worm modifies the following file(s):

  • %System%\drivers\cdaudio.sys

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\MADOWN

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\MADOWN

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Security

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
Start = "3"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
ImagePath = "\??\%System%\drivers\cdaudio.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
DisplayName = "AVPsys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
Count = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
NextInstance = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
INITSTARTFAILED = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Security
Security = "{hex value}"

It modifies the following registry entries to hide files with Hidden attributes:

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

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

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

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

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".)

Propagation

This worm drops the following copies of itself in all physical and removable drives:

  • {drive letter}:\a63grox.com

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=a63grox.com
shell\open\Command=a63grox.com

Backdoor Routine

This worm does not have any backdoor routine.

Download Routine

This worm accesses the following websites to download files:

  • http://{BLOCKED}fd.com/xhg2/ll1.rar

It saves the files it downloads using the following names:

  • %User Temp%\ll1.rar

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

Information Theft

This worm steals sensitive information such as user names and passwords, particularly for certain games.

Stolen Information

This worm sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}8.com/hhz/hc3/lin.asp
  • http://{BLOCKED}8.com/hhz/hts/lin.asp
  • http://{BLOCKED}8.com/xhg/dhh/lin.asp
  • http://{BLOCKED}8.com/xhg/hrk/lin.asp

Other Details

This worm closes application windows that contain the following strings in the title bar:

  • AVP.Product_Notification
  • AVP.AlertDialog
  • AVP.Product_Notification
  • AVP.AlertDialog

It creates the following event(s):

  • VBNMKLOOPWERUMNSOPDFGHKDQ_MN
  • MN_XADLEBCBAXCSDFGEWQCDDD0

However, as of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself

NOTES:

This worm checks the language of the system by checking the value of the following registry entry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language
InstallLanguage = "{number}"

If the number above is equivalent to 0804 (the language is in Chinese), it does not continue its routines.

It checks if the following registry key exists:

HKEY_LOCAL_MACHINE\SOFTWARE\KasperskyLab\protected\AVP7\profiles\Updater

If it exists, it creates the following registry entry to disable a particular antivirus from updating itself:

HKEY_LOCAL_MACHINE\SOFTWARE\KasperskyLab\protected\AVP7\profiles\Updater enabled = "0"

It checks if the following processes related to antivirus are running in memory:

  • ALUSCHEDULERSVC.EXE
  • ASHDISP.EXE
  • AVGNT.EXE
  • AVGRSX.EXE
  • AVP.EXE
  • AYAGENT.AYE
  • CCSVCHST.EXE
  • LIVESRV.EXE
  • UFSEAGNT.EXE
  • VCRMON.EXE
  • VSTSKMGR.EXE

It retrieves the folder where the said files are located. It then searches for any of the following component files, depending on the antivirus process it finds:

  • avast.setup
  • avgupd.exe
  • AYUpdate.aye
  • luall.exe
  • mcupdate.exe
  • preupd.exe
  • prupdate.ppl
  • setup.ovr
  • SfFnUp.exe
  • UfUpdUi.exe
  • Update.exe
  • vsupdate.dll

It searches files from the said folder with the following extensions:

  • .DLL
  • .EXE

It moves the files it finds in the system root folder and replaces the file name with {file name}.{extension}.vcd.

It attempts to steal user credentials, such as user names and passwords, related to online games. It does this by monitoring processes/services in the memory that contains the following strings:

  • agexe.exe
  • Altair(Non-PvP)
  • app.dll
  • coc.exe
  • Forthgoer
  • Leu
  • lin.bin
  • PlayOnline ID :
  • pol.exe
  • polcore.dll
  • Ragexe.exe
  • shlwapi.dll

It attempts to steal information from the following file if present on the affected system:

  • aaa.dat

It steals Yahoo! Japan credentials by monitoring the following URLs, processes, and registry key:

  • https://login.yahoo.co.jp/config/login_verify2?.src=ym
  • https://login.yahoo.co.jp/config/login?
  • YPagerj.exe
  • YahooWidgetEngine.exe
  • \Software\YahooJapan

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.618.04
FIRST VSAPI PATTERN DATE: 28 Jun 2016
VSAPI OPR PATTERN File: 12.619.00
VSAPI OPR PATTERN Date: 29 Jun 2016

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Restart in Safe Mode

[ Learn More ]

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
    • MADOWN
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • MADOWN
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • AVPsys

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
    • ahnsoft = "%System%\ahnsbsb.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\KasperskyLab\protected\AVP7\profiles\Updater
    • enabled = "0"

Step 6

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

Step 7

Search and delete this file

[ Learn More ]
There may be some 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%\ll1.rar

Step 8

Search and delete AUTORUN.INF files created by WORM_ONLINEG.M that contain these strings

[ Learn More ]
  • [AutoRun]
  • open=a63grox.com
  • shell\open\Command=a63grox.com

Step 9

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.

  • %System%\drivers\cdaudio.sys

Step 10

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_ONLINEG.M. 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 11

Scan your computer with your Trend Micro product to delete files detected as WORM_ONLINEG.M. 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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