TROJ_ONLINEG.IHC
Worm:Win32/Taterf.B (Microsoft); Generic PWS.ak (McAfee); Trojan.Packed.NsAnti (Symantec); Trojan-GameThief.Win32.OnLineGames.bkxc (Kaspersky); Worm.Win32.Taterf.b (v) (Sunbelt); Trojan.PWS.OnlineGames.KBQC (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
TECHNICAL DETAILS
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.
Installation
This Trojan drops the following copies of itself into the affected system:
- %System%\olhrwef.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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
cdoosoft = "%System%\olhrwef.exe"
It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\KAVsys
Other System Modifications
This Trojan deletes the following files:
- %System Root%\a1agmur.cmd
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It adds the following registry keys:
HKEY_CLASSES_ROOT\CLSID\MADOWN
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
Start = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KAVsys
ImagePath = "\??\%System%\drivers\klif.sys"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\MADOWN
urlinfo = "{random characters}"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
(Note: The default value data of the said registry entry is 2.)
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\Policies\
Explorer
NoDriveTypeAutoRun = "91"
(Note: The default value data of the said registry entry is 91.)
It deletes the following registry keys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\KAVsys\Enum
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\KAVsys\Security
Dropping Routine
This Trojan drops the following files:
- %System%\drivers\klif.sys
- %System%\nmdfgds0.dll
- %System Root%\autorun.inf
- %User Temp%\help1.rar
- %System Root%\a1agmur.cmd
(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.. %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://{BLOCKED}l.com/xmfx/help1.rar
This report is generated via an automated analysis system.
SOLUTION
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
Step 3
Delete this registry key
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
- KAVsys
- In HKEY_CLASSES_ROOT\CLSID
- MADOWN
Step 4
Delete this registry value
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
- cdoosoft = "%System%\olhrwef.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KAVsys
- Type = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KAVsys
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KAVsys
- Start = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KAVsys
- ImagePath = "\??\%System%\drivers\klif.sys"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\MADOWN
- urlinfo = "{random characters}"
Step 5
Restore this modified registry value
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 = ""2""
- From: Hidden = "2"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
- From: CheckedValue = "0"
To: CheckedValue = ""1""
- From: CheckedValue = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
- From: NoDriveTypeAutoRun = "91"
To: NoDriveTypeAutoRun = ""91""
- From: NoDriveTypeAutoRun = "91"
Step 6
Search and delete these files
- %System%\drivers\klif.sys
- %System%\nmdfgds0.dll
- %System Root%\autorun.inf
- %User Temp%\help1.rar
- %System Root%\a1agmur.cmd
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_ONLINEG.IHC. 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 8
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 Root%\a1agmur.cmd
Step 9
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_LOCAL_MACHINE\System\CurrentControlSet\Services\KAVsys
- Enum
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\KAVsys
- Security
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