TROJ_SASFIS.AM
Windows 2000, XP, Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Trojan may be dropped by other malware.
It modifies registry entries to enable its automatic execution at every system startup.
TECHNICAL DETAILS
21,504 bytes
PE
Yes
26 Oct 2010
Arrival Details
This Trojan may be dropped by the following malware:
Installation
This Trojan drops the following copies of itself into the affected system:
- %System%\{random file name}
(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.)
It injects itself into the following processes running in the affected system's memory:
- svchost.exe
Autostart Technique
This Trojan 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 rundll32.exe {malware file name} {random export module name}
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
Office\{version}\Word\
Security
AccessVBOM = 0
HKEY_CURRENT_USER\Software\Microsoft\
Office\{version}\Word\
Security
Level = 4
It adds the following registry keys as part of its installation routine:
HKEY_CLASSES_ROOT\idid
SOLUTION
8.900
Step 1
For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 3
Scan your computer with your Trend Micro product and note files detected as TROJ_SASFIS.AM
Step 4
Restart in Safe Mode
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\Office\{version}\Word\Security
- AccessVBOM = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Office\{version}\Word\Security
- Level = 4
Step 6
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
- idid
Step 7
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 NT\CurrentVersion\Winlogon
- From: Shell = Explorer.exe rundll32.exe {malware file name} {random export module name}
To: Shell = Explorer.exe
- From: Shell = Explorer.exe rundll32.exe {malware file name} {random export module name}
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SASFIS.AM 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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