TROJ_FAM_000072f.TOMA
Worm:Win32/Nuqel.AD, Backdoor:Win32/Bifrose.AE (Microsoft); [.au3]:W32/Autorun.worm.gen.za (McAfee); W32.Imaut.CN (Symantec); PAK:UPX, ARC:Embedded, [script.au3]:Worm.Win32.AutoIt.ux, [script.au3]:Worm.Win32.AutoIt.ux, [c:/ser (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
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 disables Task Manager, Registry Editor, and Folder Options.
TECHNICAL DETAILS
316,320 bytes
EXE
Yes
16 Oct 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.
Installation
This Trojan drops the following copies of itself into the affected system:
- %System%\winfiles.exe
- %Windows%\winfiles.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.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
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
Yahoo Messengger = "%System%\winfiles.exe"
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe winfiles.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\Installer
LimitSystemRestoreCheckpointing = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore
DisableSR = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Schedule
AtTaskMaxHours = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares
shared = "\winfiles.exe"
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\Policies\
Explorer
NoDriveTypeAutoRun = "0"
(Note: The default value data of the said registry entry is 91.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "0"
(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.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "1"
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\aut1.tmp
- %Windows%\winnt.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.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://nhatquanglane3.{BLOCKED}5.com/setting.nql
- http://nhatquanglane3.{BLOCKED}5.com/setting.xls
This report is generated via an automated analysis system.
SOLUTION
9.200
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
Identify and delete files detected as TROJ_FAM_000072f.TOMA using either the Startup Disk or Recovery Console
Step 3
Enable Registry Editor, Task Manager, and Folder options
Step 4
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\SOFTWARE\Policies\Microsoft\Windows NT
- SystemRestore
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- System
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler
- Shares
Step 5
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
- Yahoo Messengger = "%System%\winfiles.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer
- LimitSystemRestoreCheckpointing = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\SystemRestore
- DisableSR = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Schedule
- AtTaskMaxHours = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler\Shares
- shared = "\winfiles.exe"
Step 6
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_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 = "0"
To: NoDriveTypeAutoRun = ""91""
- From: NoDriveTypeAutoRun = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "0"
To: Hidden = ""2""
- From: Hidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "1"
To: HideFileExt = ""1""
- From: HideFileExt = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- SuperHidden = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe winfiles.exe"
To: Shell = ""Explorer.exe""
- From: Shell = "Explorer.exe winfiles.exe"
Step 7
Search and delete these files
- %User Temp%\aut1.tmp
- %Windows%\winnt.exe
Step 8
Scan your computer with your Trend Micro product to delete files detected as TROJ_FAM_000072f.TOMA. 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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