The Good News: Microsoft Corp will be making fewer warnings of "critical" security vulnerabilities in its products from now on,Kevin Murphy writes
The Bad News: This is because Microsoft has changed the way it advises users and administrators of vulnerabilities, raising the threshold to require a "critical" advisory.
Steve Lipner, director of security assurance at the company, said in an email circular yesterday that Microsoft has overhauled its security advisory services to provide less "confusing" technical information to end users, while still providing administrators with the details they need to rectify problems.
The company has also introduced a four-tier scale to rate the severity of vulnerabilities. Critical-Important-Moderate-Low replaces the old Critical-Moderate-Low scale. The majority of formerly critical warnings would now be classed important, according to the ranking criteria published by Microsoft.
For a vulnerability to be ranked "critical", it now would have to be of the order of magnitude of the Internet Information Services (IIS) buffer overrun that allowed the Code Red and Nimda worms to propagate automatically last year. Holes that allow, for example, files to be stolen or deleted, would now be ranked as "important".
Lipner wrote in his email, sent to security advisory mailing list subscribers, that many customers "find that the ratings fail to clearly identify the most serious issues." He added: "We have modified the Severity Rating criteria to help customers more easily evaluate the impact of security issues."
"Our increased attention to consumer communication will only raise the profile of security threats," a Microsoft spokesperson said. "The changes we've made will not affect the number of security bulletins we ship. Our goal is simply to make it easier for users to apply necessary patches with the appropriate level of urgency."
It is reckoned that almost half of the over 60 security advisories Microsoft has issued this year have been of "critical" holes. The fact that none of these have yet been exploited on as grand a scale as Code Red exploited the IIS hole suggests that truly critical warnings a few and far between.
Shortly, Microsoft will introduce an End User Security Notification Service, which will direct non-technical Microsoft users to patches, explaining vulnerabilities without the emphasis on technical details. Systems administrators will still be able to receive the technically oriented bulletins as before.