Threat behavior
Trojan:Win32/Agent!246A is an Internet Explorer Browser Helper Object (BHO) implemented as a DLL plug-in that allows attackers to customize and control Internet Explorer.
When Trojan:Win32/Agent!246A runs, it takes the following actions:
- Copies itself to the Windows system folder as 'rwera21s1.dll' folder
- Adds the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Ppc
Trojan:Win32/Agent!246A modifies the registry to install the dropped DLL as a BHO in Internet Explorer as follows:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{AA7F2000-EA05-489d-900C-3C7C0A5497A3}
Name = InprocServer32
Key = "%Windir%\System32\rwera21s1.dll
Trojan:Win32/Agent!246A creates 'config.xml' in the Windows system folder, logs user activities to this file and sends the collected information to the remote attacker. Trojan:Win32/Agent!246A also contains functionality to display contextual popup advertising, triggered by visiting certain popular Web sites.
Prevention
Take the following steps to help prevent infection on your system:
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Enable a firewall on your computer.
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Get the latest computer updates.
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Use up-to-date antivirus software.
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Use caution with attachments and file transfers.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows XP Internet Connection Firewall.
To turn on the Internet Connection Firewall in Windows XP
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Click Start, and click Control Panel.
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Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
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Click Change Windows Firewall Settings.
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Select On.
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Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. You can use the Automatic Updates feature in Windows XP to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows XP
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Click Start, and click Control Panel.
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Click System.
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Click Automatic Updates.
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Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information, see http://www.microsoft.com/athome/security/downloads/default.mspx
Use caution with attachments and file transfers
Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.
