Rule:

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Sid:
720

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Summary:
This event is generated when email is received from a Post Office Protocol (POP) server that may contain an attachment with the Snow White worm.

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Impact:
Possible system compromise.  The worm can alter system files and registry key settings. 

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Detailed Information:
The Snow White worm, also known as Hybris, may contain text with a unique misspelling of "Suddlently".  This worm attempts to write to the wsock32.dll library.  It may also attempt to alter registry key settings.

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Affected Systems:
Microsoft Win32 systems.

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Attack Scenarios:
The worm is spread by e-mail and attempts to infect other hosts when a user opens the e-mail attachment. 

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Ease of Attack:
Simple

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False Positives:
This event is triggered when an e-mail is received from a POP server that contains the misspelled word "Suddlently".

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False Negatives:
None known.

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Corrective Action:
Make sure that the suspected infected host has the most current anti-virus software.  

Run a virus scan on the suspected infected host.

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Contributors:
Original rule writer unknown.
Documented by Steven Alexander<alexander.s@mccd.edu>
Sourcefire Research Team
Judy Novak <judy.novak@sourcefire.com>

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Additional References:

F-Secure:
http://www.f-secure.com/v-descs/hybris.shtml

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