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larrydrude

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double Extension prevention

Is there a way to prevent someone from executing a double file extension received in an e-mail or other source?

Ex: .pdf.exe
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Rich Rumble
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Don't we all wish that were true... If you're using outlook as a client it blocks exe's, but not zips, which the users extract and then run :) You can however try to prevent this with more outlook or exchange filters http://support.microsoft.com/kb/837388
you can also search inside compressed attachments:
http://technet.microsoft.com/en-us/library/ff714963.aspx
http://technet.microsoft.com/en-us/library/ff714983.aspx 

Microsoft assumes the file ext starts at the right, moves left until the first dot... that's all, you can't make it understand ".tar.gz" is one file ext. It sees the .gz and that is all.
-rich
Wouldn't it be great to have the e-mail client (and attachments) run in an isolated security container, separate from your primary OS?  When a malicious process is executed it would only affect that virtual space.  This environment could easily be reverted to a clean state using snapshots.  Another approach to this would be running your email client (and attachments) in the cloud, whereas the cloud based OS has similar snapshot/revert capabilities.

There are products available that do just this, such as Invincea or spoon.net

BTW, you can show file name extensions to achieve some higher degree of visibility.  

To show file name extensions in Windows Explorer, follow these steps:

For Windows Vista, Windows 7, and Windows Server 2008
    Start Windows Explorer, you can do this by opening up any folder.
    Click Organize.
    Click Folder and search options.
    Click the View tab.
    Scroll down until you notice Hide extensions for known file types, un-check this line by clicking the check box.
    Note To hide file name extensions, check this line.
    Click OK

For Windows 2000, Windows XP, and Windows Server 2003
    Start Windows Explorer, you can do this by opening up any folder.
    Click Tools, and then click Folder Options.
    Scroll down and then click Folder and search options.
    Click the View tab.
    Scroll down until you notice Hide extensions for known file types, un-check this line by clicking the check box.

    Note To hide file name extensions, check this line.
    Click OK
That would be an option any antivirus-e-mail-plugin should offer.
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McKnife
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At least https:#a39877833 is a possible solution since this option will exist in most e-mail scanners and it does what he is looking for.