Security Pros: Microsoft's July Patch Ratings Misleading

Security pros warned IT administrators not to sleep on the security fixes issued by Microsoft in this month's Patch Tuesday because of their ratings.

Microsoft classified as "important" all four of its July security bulletins, which affect Microsoft SQL Server, Exchange Server, Windows DNS (Domain Name System) and Windows Explorer. However, some say IT admins still need to take them seriously.

"Many corporations hold not only their basic business information, but also their customer [or] patient data and critical intellectual property in Microsoft SQL Servers databases, or transmit these types of data via Microsoft Exchange servers," said Don Leatham, director of solutions and strategy at Lumension Security.

"Companies that depend heavily on SQL and Exchange servers to manage and store customer/patient data and intellectual property should evaluate the criticality of these updates and possibly address them as a 'critical'-level security update," Leatham said.

The SQL Server bulletin addresses four vulnerabilities across a number of products, including SQL Server 2000, SQL Server 2005 and SQL Server 7.0. According to Microsoft, each of the flaws allows for privilege escalations that enable an attacker to execute code and take complete control of an affected system.

A second bulletin addresses two cross-site scripting issues in Outlook Web Access for Microsoft Exchange Server. One involves Exchange Server not sufficiently validating e-mail fields when opening mail from within an individual client's OWA session, while the other deals with Exchange Server improperly validating HTML when rendering e-mail from within an individual OWA client session.

In both cases, to exploit the vulnerability an attacker would have to convince a user to open an e-mail that would run malicious script from within an individual OWA client. If the malicious script is executed, the script would run in the security context of the user's OWA session and could perform any action the user could perform such as reading, sending and deleting e-mail as the logged-on user, according to Microsoft.

The flaw exists in all supported editions of Microsoft Exchange Server 2003 and Microsoft Exchange Server 2007.

A third bulletin involves a fix for Windows Explorer that affects Windows Vista and Windows Server 2008 implementations and can be exploited when a specially crafted saved-search file is opened and saved. An attacker who successfully exploited this vulnerability could take complete control of an affected system, according to the Microsoft advisory.

The final bulletin patches two issues in DNS that can lead to DNS cache poisoning. One of the problems is due to the Windows DNS service in the Windows DNS client and DNS server not providing enough entropy when performing DNS queries, and is part of of a coordinated release among several vendors to address the issue.

"It sure seems like Microsoft is rewriting their definitions this month," said Eric Schultze, CTO of Shavlik Technologies, adding that the prospect of having corporate e-mail spoofed or deleted could be critical for many organizations. "I can see where Microsoft is coming from, and it's a very rosy side of Redmond."