WORM_TATERF.RNA
Worm.Win32.Taterf.b (v) (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
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
169,730 bytes
EXE
Yes
11 May 2012
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 copies of itself into the affected system:
- %System%\ahnsbsb.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 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"
It registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{AF4DA69B-E1D6-469A-855B-6445294857D4}
Other System Modifications
This worm adds the following registry keys:
HKEY_CLASSES_ROOT\IEHlprObj.IEHlprObj.1
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
IEHlprObj.IEHlprObj.1\CLSID
HKEY_CLASSES_ROOT\IEHlprObj.IEHlprObj
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
IEHlprObj.IEHlprObj\CurVer
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\ProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\VersionIndependentProgID
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\Programmable
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\InprocServer32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0\
FLAGS
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0\
0
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0\
0\win32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0\
HELPDIR
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}\ProxyStubClsid
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}\ProxyStubClsid32
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}\TypeLib
HKEY_CLASSES_ROOT\CLSID\MNDOWN
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\InprocServer32
ThreadingModel = "Apartment"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}\TypeLib
Version = "1.0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\MNDOWN
urlinfo = "tmlhead/headbody!-- vbe --/body/html"
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.)
Dropping Routine
This worm drops the following files:
- %System%\ahnxsds0.dll
- %System%\ahnfgss0.dll
- %System Root%\autorun.inf
- %User Temp%\ll1.rar
- %System Root%\lot.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.. %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 worm connects to the following possibly malicious URL:
- http://{BLOCKED}g.com/1m/c.rar
- http://{BLOCKED}fd.com/xhg2/ll1.rar
SOLUTION
9.200
9.102.02
14 May 2012
9.103.00
14 May 2012
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
Close all opened browser windows
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_CLASSES_ROOT
- IEHlprObj.IEHlprObj.1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\IEHlprObj.IEHlprObj.1
- CLSID
- In HKEY_CLASSES_ROOT
- IEHlprObj.IEHlprObj
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\IEHlprObj.IEHlprObj
- CurVer
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
- {AF4DA69B-E1D6-469A-855B-6445294857D4}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}
- ProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}
- VersionIndependentProgID
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}
- Programmable
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}
- InprocServer32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
- {AF4DA692-E1D6-469A-855B-6445294857D4}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}
- 1.0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0
- FLAGS
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0
- 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0\0
- win32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{AF4DA692-E1D6-469A-855B-6445294857D4}\1.0
- HELPDIR
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
- {AF4DA69C-E1D6-469A-855B-6445294857D4}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}
- ProxyStubClsid
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}
- ProxyStubClsid32
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}
- TypeLib
- In HKEY_CLASSES_ROOT\CLSID
- MNDOWN
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
- ahnsoft = "%System%\ahnsbsb.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AF4DA69B-E1D6-469A-855B-6445294857D4}\InprocServer32
- ThreadingModel = "Apartment"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{AF4DA69C-E1D6-469A-855B-6445294857D4}\TypeLib
- Version = "1.0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\MNDOWN
- urlinfo = "tmlhead/headbody!-- vbe --/body/html"
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_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 7
Search and delete these files
- %System%\ahnxsds0.dll
- %System%\ahnfgss0.dll
- %System Root%\autorun.inf
- %User Temp%\ll1.rar
- %System Root%\lot.exe
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_TATERF.RNA. 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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