Blocking and Unblocking External Content


When you work with external content (content from the Internet or an intranet that is linked to a presentation), you should be careful with the source of the content. Hackers have developed what are called Web beacons-these send back, or “beacon,” information from your computer to the server that hosts the actual external content. For example, maybe you have opened a presentation that contains images. As soon as you open the file, the image downloads and sends information about where the file is located to the original server that sent the presentation. Scary, isn’t it? You didn’t do anything except open the presentation. Other types of Web beacons that could be embedded in a PowerPoint 2007 presentation are linked media and data connections.

Linked media are typically media objects, such as a sound, linked to an external server. When a presentation is opened, the media object plays as part of the presentation. When it plays, it triggers the execution of code that runs a malicious script on your computer.

Data connections involve Excel 2007, which can impact you if you are using an Excel 2007 file with one of these connections. Simply opening the workbook involved triggers the execution of code that accesses databases by using stolen credentials.

You’ll know when there is unethical external content in your presentation because when you open the file, the Message Bar will notify you that content has been blocked. Also on the Message Bar is the Options button, which lets you unblock the content in question. If you’re positive the content is from a trustworthy source, it’s best to move the file to a trusted location-usually a folder on your hard drive or on a network. After you place a file into the trusted location, you can open it from then on without further checks by the Trust Center security feature. See the next section for more details about the Trust Center.

Homographs and phishing schemes can invade your PowerPoint 2007 files. See the “Setting Up Security Alerts and Trusted Publishers” section on page 608 to learn more about the automatic security features of PowerPoint 2007. For more information about the security features of the Microsoft Office system, see Chapter 3, “Managing Security and Privacy in the 2007 Office System.”




2007 Microsoft Office System Inside Out
2007 MicrosoftВ® Office System Inside Out (Bpg-Inside Out)
ISBN: 0735623244
EAN: 2147483647
Year: 2007
Pages: 299

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