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Microsoft Warns of New Video ActiveX Vulnerability
ucanlookitup writes "Microsoft has warned of a 'privately reported' vulnerability affecting IE users on XP or Windows Server 2003. The vulnerability allows remote users to execute arbitrary code with the same privileges as the users. The vulnerability is triggered when users visit a web site with malicious code. 'Security experts say criminals have been attacking the vulnerability for nearly a week. Thousands of sites have been hacked to serve up malicious software that exploits the vulnerability.' The advisory can be found at TechNet. Until Microsoft develops a patch, a workaround is available."
Internet Explorer 7.0 and 8.0 already do this in Vista. By default it runs in a double sandbox where even if the current user has admin privileges the process runs as a standard user that is further constrained to only be able to read certain parts of the file system but not write. Anything beyond that requires negotiation via a specific broker process just to attain a level of security equal to that of a standard constrained user.
These types of vulnerabilities affect all browsers. ActiveX in Internet Explorer in this case is really no different than NSAPI in Firefox or Opera. It is simply an object model for loading native plug-ins into the process. That plug-in runs in-process with the same rights and privileges as the hosting process. If there is a vulnerability in a PDF plug-in on Linux then it can be exploited through Firefox and there is nothing Firefox or Opera can do to prevent it and it would likely affect all browsers equally.
I agree that the answer appears to be to isolate and constrain. That is what Microsoft has done and Google is following suit. That is why this vulnerability does not affect Vista or Windows Server 2008, or rather an exploit for the vulnerability is neutered by the fact that once it has broken in it cannot do anything malicious.
http://www.mozilla.com/en-US/firefox/