Microsoft has patched nine vulnerabilities in Windows, Exchange, SQL Server and the company's Domain Name System (DNS) server and client software.

All nine flaws were rated "important" by Microsoft, the second-highest threat rating in the company's four-step scoring system.

One of the Microsoft fixes for Windows DNS was part of a group of patches issued Tuesday by software vendors to plug a multi-platform hole. The researcher who uncovered the vulnerability called the group patch effort the "largest synchronised security update in the history of the Internet."

Microsoft patched its iterations of DNS in MS08-037, the security bulletin that called out two DNS bugs in every supported version of Windows except Vista.

"We've had four updates to Microsoft's DNS since 2007 - and one led to a bot, Rinbot, in April 2007," noted Andrew Storms, director of security operations at nCircle Network Security.

Storms was referring to the episode last year when researchers spotted then-new variants of Rinbot exploiting a zero-day flaw in Windows DNS Server Service. The most recent patch for Windows DNS was released as MS08-020 in April, part of that month's eight-update, 10-fix batch of updates.

Eric Schultze, chief technology officer of Shavlik Technologies, picked a different Microsoft update to tout Tuesday. He focused on MS08-038, a bulletin that outlined a remote code vulnerability in Windows Vista and Windows Server 2008 that involves the saved search feature and its associated file format in those operating systems.

"I say that one only because it's entirely unclear if browsing to a malicious site can [trigger the vulnerability] or if the user has to save and then open a [malicious] saved search file," Schultze said. "Given that it's so unclear, I'd patch that one first."

Microsoft also issued MS08-039 and MS08-040 Tuesday, the former a two-patch update to Exchange 2003 and 2007, the latter a four-patch update for Microsoft's SQL Server software, including the database components bundled with Windows.

"Both are important to patch as soon as possible," said Storms, "not so much because of the attack methods or the risk they may present to the organisation, but the high importance of email and databases in the enterprise, and the high administrative duty in patching and testing."

Because Exchange and SQL Server are critical components in corporations relying on Microsoft's software, IT staff must take caution in making any changes, said Storms. "There's a lot of overhead risk," he said. "Anytime you introduce a change, there's a risk of it breaking something else. So these updates heighten the overhead risk and administrative cost, because you're talking about e-mail and databases."

Another factor that should be considered, Storms continued, is the widespread use of SQL injection attacks by hackers to compromise sites and turn them into malware-spreading domains. The four fixes in MS08-040 don't address flaws that attackers have used to hack sites - Microsoft has been adamant that SQL injection attacks succeed because of poorly-coded ASP code, not vulnerabilities in SQL Server itself - but could, Storms argued, be dissected by hackers and used in conjunction with injection attacks.

July's security updates can be downloaded and installed via the Microsoft Update and Windows Update services, as well as through Windows Server Update Services.