[ISN] Microsoft's Security Disclosures Come Under Fire

[InfoSec News]

http://www.eweek.com/article2/0,1895,1949279,00.asp

By Ryan Naraine 
April 13, 2006 

Is Microsoft silently fixing security vulnerabilities and deliberately
obfuscating details about patches in its monthly security bulletins?

Matthew Murphy, a security researcher who has worked closely with the
MSRC (Microsoft Security Response Center) in the past, is accusing the
software maker of "misleading" customers by not clearly spelling out
exactly what is being patched in the MS06-015 bulletin released on
April 11.

That bulletin, rated "critical," contained patches for a remote code
execution hole in Windows Explorer, the embedded file manager that
lets Windows users view and manage drives, folders and files.

However, as Murphy found out when scouring through the fine print in
the bulletin, the update also addressed what Microsoft described as a
"publicly disclosed variation" of a flaw that was reported in May 2004
(CVE-2004-2289.)

In an entry posted to the SecuriTeam blog, Murphy noted that the
vulnerability that is documented was privately reported, but the
"variation" that was also patched has been publicly known for 700+
days.

"In that case, the issue that is truly the 'variation' is the issue
that was discovered and reported privately after the public
disclosure," he said.

"[The] information as published is extremely misleading and
Microsoft's choice not to document a publicly reported vulnerability
is not one that will be for the benefit of its customers' security,"  
Murphy said.

In an interview with eWEEK, Murphy said another "throwaway line" in
the bulletin also raised questions about whether a flaw he reported in
August 2005 was silently fixed.

The bulletin refers to a "Defense in Depth change" that ensures that
consistent prompting occurs in "Internet zone drag and drop
scenarios."

That wording, Murphy said, "sounds suspiciously like an attempt to
plug the vulnerability I reported publicly in February, which is
CVE-2005-3240."

Murphy originally reported that vulnerability to the MSRC in August
2005, but held off on publishing the details for six months. During
that time, Murphy and MSRC officials haggled over the severity of the
bug and Microsoft made it clear it had no plans to issue a security
update to provide a fix, Murphy said.

The company said the fixes would be included in Service Pack 2 of
Windows Server 2003 and Service Pack 3 of Windows XP. "Microsoft's
internal risk assessment concluded that this issue was not
sufficiently serious to be fixed in a security bulletin. This
conclusion appears fundamentally inconsistent with the way related
issues were handled by Microsoft," Murphy said.

"I disagree with the technical conclusion behind Microsoft's decision
and I further find the time frame of delivery and deployment for
maintenance releases to be largely unsuitable for security fixes of
any significant magnitude," he said.

Murphy has not yet tested the patch to determine whether the
drag-and-drop issue was actually fixed, but, even without testing, he
argues that the way the information was released leaves everyone
guessing.

"Microsoft needs to be much more transparent about the real nature of
the threats customers are facing. Microsoft doesn't patch phantom
vulnerabilities that don't exist or unrealistic science-fiction attack
scenarios. Microsoft's under-documentation of these vulnerabilities
leaves those charged with deploying patches in a tough spot," he said.

"You simply don't know what the patches are for. It's virtually
impossible to make a determination about a deployment time frame if
not deploying a patch has the potential to place you at an additional,
unknown risk. As a result, administrators may deploy patches
unnecessarily, erring on the side of caution (and risking
compatibility problems in the process), or they may choose not to
deploy based on incomplete information. Individuals making these kinds
of decisions deserve better information," Murphy said.

Murphy said the MS06-015 bulletin "should be revised or completely
rewritten, with the objective of providing sensible, coherent and
complete information to customers."

Microsoft, based in Redmond, Wash., declined requests for an interview
to discuss the issue. Instead, the company sent a statement to eWEEK
to stress that all the publicly disclosed vulnerabilities fixed by
MS06-015 are addressed in the bulletin documentation, listed under the
"Vulnerability Details" section and denoted by their individual CVE
numbers.

"[We] have a working relationship with Matt and, based on our ongoing
discussions with him, view his blog posting as welcome feedback for
how we can continue to improve our security bulletins," the statement
read.

The statement said "all publicly disclosed vulnerabilities" excludes
Murphy's report, but even that claim is "false," Murphy said.

"The bulletin patches a CVE that doesn't have its own individual
denotation. The bottom line is, Microsoft's claim that every 'publicly
disclosed vulnerability' is denoted specifically is bizarre, because
they've yet to answer one of the criticisms in the blog post, which is
that they don't provide meaningful information about this 'variation'
that's allegedly patched," he said.

Regarding Microsoft's statement, Murphy added, "That still doesn't
answer the question of where this other 'Defense in Depth' change was
originated. There's no specific threat that it's identified as
correcting, so it seems almost random."

Ironically, these questions about transparency and disclosure come
less than a month after an MSRC official criticized Apple for the way
it handles security guidance to customers.

"Look, the only way you can tackle security issues is by getting out
ahead of them and clearly communicating to your users the threat, and
the clear guidance on how to be safe," MSRC program manager Stephen
Toulouse said in response to what he described as the "recent trials
and tribulations of Apple in the security space."

Now, Murphy said, the shoe is on the other foot and Microsoft is just
as guilty as Apple. "Every time Microsoft seems to be getting the
security pitch right, one gets thrown in the dirt. Microsoft needs a
new ball," he said.