A flaw that when exploited could allow an attacker to take control of a user's system exists in Microsoft's Internet Explorer and Office for the Mac, Microsoft warned late Tuesday.
The Redmond, Washington, software giant released a cumulative patch that fixes all vulnerabilities affecting Internet Explorer 5.1 for Macintosh and Office v. X previously identified by Microsoft, plus two new vulnerabilities. Microsoft in a security bulletin urged all customers running the Internet Explorer Web browser and Office for Macintosh to apply the "critical" patches.
The most serious of the two new vulnerabilities is a buffer overrun flaw that affects both Internet Explorer and Office for the Mac. An attacker could run arbitrary code on a user's Mac by creating a specially formed Web page. The user would have to visit that page, view it as e-mail in Outlook or Entourage, or open a Mac Office file with the page for an attack to be carried out, Microsoft said. Entourage is the e-mail client and personal information management program included with Office v. X.
The second newly patched vulnerability allows an attacker to run AppleScript on a user's machine, without first launching the Helper application. This flaw affects Internet Explorer for Mac OS 8 and 9 only, Microsoft said. An attacker could craft a Web page that would, for example, shut down a vulnerable Mac if its user were to visit the page containing the malicious code.
AppleScript is a system-level scripting level used to automate common tasks, such as shutting down the computer or closing windows. An attacker can only run AppleScripts already on the system, there is no way for an attacker to deliver a script of choice through this vulnerability, Microsoft said.
Microsoft's security bulletin MS02-019 can be found online at:http://www.microsoft.com/technet/security/bulletin/MS02-019.asp