Bugs Found to Affect SQL Server
- By Scott Bekker
- December 27, 2001
Microsoft Corp. issued patches in late December for two flaws affecting users of its SQL Server database.
Both vulnerabilities could be exploited in either of two ways. "The most direct way would be for the attacker to simply load and execute a database query that calls one of the affected functions," according to Microsoft's security bulletin.
"Alternatively, if a Web site or other database front-end would accept and process arbitrary queries, it could be possible for the attacker to provide inputs that would cause the query to call an affected function with the appropriate parameters," the bulletin said.
The company recommended that all users of SQL Server 7.0 and SQL Server 2000 immediately apply a patch that fixes a flaw that could allow an attacker to run code on a compromised machine.
Microsoft urged more caution in deploying the second patch for a denial of service vulnerability in the C runtime of Windows NT 4.0, 2000 and XP that is exposed primarily through the use of SQL Server.
The C runtime vulnerability is less severe -- denial of service as opposed to the SQL flaw that can allow code to be executed. However, the C runtime plays a crucial role in the operating system itself, causing Microsoft to warn: "While we are confident that both patches are well-tested, if there were a regression error in the C runtime, the effects would likely be serious and widespread." A problem with the C runtime, for example, could cause problems with booting a machine, Microsoft noted.
A more thoroughly tested version of the C runtime fix will be included in Windows 2000 Service Pack 3 and Windows XP Service Pack 1.
Microsoft gave the SQL Server flaw only a "moderate" severity rating due in part to the mitigating factors that best practices would box out attackers from being able to take advantage of the flaw. The C runtime flaw rated only a "low" risk from Microsoft.
Scott Bekker is editor in chief of Redmond Channel Partner magazine.