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 Microsofts 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. “Microsofts 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 Microsofts 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 doesnt patch phantom vulnerabilities that dont exist or unrealistic science-fiction attack scenarios. Microsofts under-documentation of these vulnerabilities leaves those charged with deploying patches in a tough spot,” he said.
“You simply dont know what the patches are for. Its 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 Murphys report, but even that claim is “false,” Murphy said.
“The bulletin patches a CVE that doesnt have its own individual denotation. The bottom line is, Microsofts claim that every publicly disclosed vulnerability is denoted specifically is bizarre, because theyve yet to answer one of the criticisms in the blog post, which is that they dont provide meaningful information about this variation thats allegedly patched,” he said.
Regarding Microsofts statement, Murphy added, “That still doesnt answer the question of where this other Defense in Depth change was originated. Theres no specific threat that its 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.