Microsoft Outlook is a personal information manager from Microsoft, and is part of the Microsoft Office.
Although often used mainly as an e-mail application, it also provides calendar, task and contact management.
It can be used as a stand-alone application, but can also operate in conjunction with Microsoft Exchange Server to provide enhanced functions for multiple users in an organisation, such as shared mailboxes and calendars, public folders and meeting time allocation.
Versions for Microsoft Windows include:
Microsoft also released several versions of Outlook for the Apple Macintosh; however, most mail features were disabled after Office 98. After Office 98, Entourage replaced Outlook on Macintosh systems, however in 2001, Microsoft released Outlook 2001 for Mac to allow Classic users to access Exchange servers.
Outlook Express is a slimmed-down email, newsgroup, and contact management application that Microsoft makes available at no charge, in conjunction with the Internet Explorer web browser. Other than the confusingly similar name it has very little in common with Outlook.
One of Microsoft's goals is for the email client to be easy to use. However, the embedded automation and lack of security features compared to competitors (omitted to avoid inconveniencing unsophisticated users) have been repeatedly exploited by malicious hackers using email viruses. These typically take the form of an email attachment which executes on the user's machine and replicates itself by mass-mailing the user's or Exchange server's address list. Examples of such viruses are the Melissa and Sobig worms. Other programs have exploited Outlook's HTML email capabilities to execute malicious code or confirm that email addresses are valid targets for spam. The noteriety of the worms and other viruses has gained Outlook a reputation as a highly insecure email platform.
Famous Unix programmer Bill Joy has suggested that Outlook is insecure largely because it was written in C, making it easy to write programs to exploit it. He also believes the widespread use of Outlook is a major contributing factor in the proliferation of spam. His views are shared by many leading IT professionals.
As part of its Trusted Computing initiative, Microsoft has recently taken corrective steps to fix Outlook's reputation in its latest incarnation, Office Outlook 2003. Among the most publicized security features are that Office Outlook 2003 does not automatically load images in HTML emails, and includes a built-in spam filter. The base code is also said to be much more secure.
As of July 2005, this most recent release has been well received, and regarded as the primary driver of Office upgrades among business users. Instances of new worms have slowed significantly, however, due to the release of numerous security updates and Service Packs which have corrected the known vulnerabilities exploited by previous viruses.
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