Malicious Code Exploit Discovered in Microsoft Office -- Microsoft Certified Professional Magazine Online

Malicious Code Exploit Discovered in Microsoft Office

By Scott Bekker
10/29/1999

Finjan Software (www.finjan.com) announced that they have discovered a new exploit involving Microsoft Windows scrap files that could be used to deliver Trojan attacks. Microsoft Office applications can be used to create "scrap" files (.SHS extension) to hide executable programs.

Because the file extension on .SHS files is always hidden, a file can be falsely named with a harmless-seeming file extension (.TXT, .JPG, .GIF), which a user will be more likely to open. Once opened, a scrap file will transmit the Trojan executable program to the user's machine.

Microsoft Windows scrap files are created when a file is copied into an open Microsoft Office document and then copied and pasted onto the Windows desktop. The new scrap file is created with the hidden file extension .SHS, but can easily be renamed by a malicious user. When distributed via e-mail messages or instant message file transfer or other Web-based media, a scrap file's extension becomes visible, but once saved to the hard drive, the .SHS extension will disappear again.

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.

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