TROJ_SCAR.GM
Windows 98, ME, NT, 2000, XP, Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan checks for the presence of the following processes which are related to Outpost Personal Firewall and ZoneLabs Firewall Client. It terminates if either of the said processes exist. This is to ensure that it runs uninterrupted.
TECHNICAL DETAILS
118,272 bytes
PE
Yes
05 Nov 2009
Steals information
Installation
This Trojan drops copies of itself in the Windows system folder and appends garbage code to the dropped copy to avoid easy detection. The dropped copies uses the following file names:
- sdra64.exe
It drops the following non-malicious file:
- %System%\lowsec\local.ds - copy of the encrypted downloaded file
- %System%\lowsec\user.ds - used to save the gathered information
(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 creates the following folders with attributes set to System and Hidden to prevent users from discovering and removing its components:
- %System%\lowsec
(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 adds the following mutexes to ensure that only one of its copies runs at any one time:
- _AVIRA_2108
- _AVIRA_2109
It injects itself into the following processes as part of its memory residency routine:
- SVCHOST.EXE
- WINLOGON.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
Userinit = %System%\userinit.exe, %System%\sdra64.exe,
(Note: The default value data of the said registry entry is %System%\userinit.exe,.)
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Network
UID = {Computer name}_{Random numbers}
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 0
Information Theft
This Trojan accesses the following site to download its configuration file:
- http://113.11.194.175/uk/denwer.doc
Stolen Information
This Trojan saves the stolen information in the following file:
- %System%\lowsec\user.ds
(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.)
Other Details
This Trojan checks for the presence of the following processes, which are related to Outpost Personal Firewall and ZoneLabs Firewall Client:
- outpost.exe
- zlclient.exe
SOLUTION
8.900
07.310.05
15 Jul 2010
7/15/2010 12:00:00 AM
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_SCAR.GM using the Recovery Console
Step 3
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: Userinit=%System%\\userinit.exe, %System%\\sdra64.exe,
To: %System%\\userinit.exe,
- From: Userinit=%System%\\userinit.exe, %System%\\sdra64.exe,
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_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\SharedAccess\\Parameters\\FirewallPolicy\\StandardProfile
- EnableFirewall =0
- EnableFirewall =0
- In HKEY_LOCAL_MACHINE\\Software\\Microsoft\\Windows NT\\CurrentVersion\\Network
- UID ={Computer name}_{Random numbers}
- UID ={Computer name}_{Random numbers}
Step 5
Scan your computer with your Trend Micro product to delete files detected as TROJ_SCAR.GM. 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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