[Infowarrior] - MS: Word 2007 crashes aren't a bug, they're a feature

[Richard Forno]

Microsoft: Word 2007 crashes aren't a bug, they're a feature
Gregg Keizer
 http://www.computerworld.com/action/article.do?command=viewArticleBasic&art
icleId=9016401&pageNumber=1

April 12, 2007 (Computerworld) The Word 2007 bugs pegged as security
vulnerabilities by an Israeli researcher are nothing of the sort, Microsoft
Corp. said today. Instead, the application crashes reported as flaws are
actually by design.

The researcher who posted details earlier this week of the bugs reacted by
offering screenshots of the Word crashes and wondering why Microsoft
disputed his findings.

On Monday, Mati Aharoni of Offensive Security warned of three new flaws in
Word 2007 on the Milw0rm and SecurityVulns.com security sites, and posted
malformed Word documents as proof-of-concepts. Microsoft, however, seemed
unconcerned.

Late yesterday, a company spokeswoman repeated the company's earlier
contention that the Microsoft Security Response Center's (MSRC)
investigation, "found that none of these claims demonstrate a vulnerability
in Microsoft's Word 2007 or any part of the Microsoft Office System."

When asked to clarify that statement, she acknowledged Microsoft won't
classify the flaws as security problems. Rather, the behavior of Word 2007
is a feature, not a bug. "In fact, the behavior observed in Microsoft Word
2007 in this instance is a by-design behavior that improves security and
stability by exiting Microsoft Word when it has run out of options to try
and reliably display a malformed Word document," the spokeswoman said.

She went on to suggest that it is no big deal if Word 2007 did crash under
those circumstances, a scenario that could lead to the loss of any unsaved
data. "The sample code in [Aharoni's] postings cause Microsoft Word to
crash, and users can restart the application to resume normal operations."

The stance was not out of character for the MSRC, which in the past has
separated bugs that allow code execution or rights elevation from those that
result in a denial-of-service-style situation. Previously, it has refused to
label some crash-inducing problems as vulnerabilities, or patch them outside
of a service pack.

That's the same position taken by David LeBlanc, one of Microsoft's secure
code gurus, and Michael Howard, the co-author of the just-released Writing
Secure Code for Vista. "You may rightfully say that crashing is always bad,
and having a server-class app background, I agree. Crashing means you made a
mistake, bad programmer, no biscuit," said LeBlanc in an MSDN blog.
"However, crashing may be the lesser of the evils in many places. The theory
is that it is better to crash, at least with client apps, than it is to be
running the bad guy's shell code."

Office 2007 uses this strategy, said LeBlanc, who, like the MSRC, objected
to classifying a denial-of-service-like result as an attack. "I really take
issue with those who would characterize a client-side crash as a denial of
service," he said. "If you can crash my app so that I can't restart it, or
have to reboot my system, well, okay, that's a DoS. If you blew up my app,
and I just don't load that document again, big deal."

For his part, Aharoni was puzzled by media reports that claimed Microsoft
contested the bugs themselves, not that the flaws weren't to be considered
true vulnerabilities, and responded by posting screenshots of the Word 2007
crash. "I've recieved [sic] many mails from full disclosure members
confirming the crash," he also said on his blog today. "I fully hope that
Microsoft will find the resources to figure this out."

The company said it will continue to investigate, in case earlier editions
of the word processor, which don't include code that purposefully crashes
the app, are found to vulnerable. "Our investigation into the possible
impact of these claims on other versions of Microsoft Office is continuing,"
said the spokeswoman.