Rule:

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Sid:
163

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Summary:
This event is generated when Trojan Horse activity is detected from the program WinCrash.

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Impact:
Limited control of the targeted machine.

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Detailed Information:
The Trojan changes system registry settings to add the WinCrash server to programs normally started on boot. Due to the nature of this Trojan it is unlikely that the attacker's client IP address has been spoofed.

The server portion opens TCP ports 5472 for version 1, and 2583 for version 2 to establish a connection between client and server.

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Affected Systems:
	Windows 95
	Windows 98
	Windows ME

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Attack Scenarios:
This Trojan may be delivered to the target in a number of ways. This event is indicative of an existing infection being activated. Initial compromise can be in the form of a Win32 installation program that may use the extension ".jpg" or ".bmp" when delivered via e-mail for example.

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Ease of Attack:
This is Trojan activity, the target machine may already be compromised. Updated virus definition files are essential in detecting this Trojan.

The Trojan server is named server.exe.

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False Positives:
None Known

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False Negatives:
None Known

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Corrective Action:

Edit the system registry to remove the extra keys or restore a previously known good copy of the registry.

Affected registry keys are:

	HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\

Registry keys added are:

	WinManager

Removal of this entry is required.

Delete the file server.exe

Edit the win.ini file to remove any references to the Trojan file.

Ending the Trojan process is also necessary. A reboot of the infected machine is recommended.

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Contributors:
Original Rule Writer Max Vision <vision@whitehats.com>
Sourcefire Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>

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Additional References:

Whitehats arachNIDS
http://www.whitehats.com/info/IDS36

Dark-e:
http://www.dark-e.com/archive/trojans/wincrash/index.html

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