"Microsoft downplays a recent DNS vulnerability in all Microsoft operating systems (XP, Vista, 2000, and 2003), claims Amit Klein, the security researcher who published the original vulnerability description (PDF) earlier this month. According to Klein, the description in Microsoft's Secure Windows Initiative blog entry is misleading, contains disinformation about the DNS transaction ID algorithm, and downplays the severity of the issue. Klein refutes Microsoft's claim that there is no way to reproduce the next transaction ID, given a series of observed transaction IDs. He shows that this is possible in his paper, which Microsoft had before publishing the SWI post, as well as on the series of data provided in the SWI blog itself."
,they(M$ etc) can hence,claim lesser vulnerabilities by this hiding practice