A plethora of patches from Microsoft wings its way into our in-box this morning.

There are bug fixes for Microsoft Metadirectory Services, SQL Server, Exchange 5.5 and a reissued patch for Media Player. To round things up there's also a Cumulative Patch for SQL Server 2000.

First up, and most serious, two buffer overflow vulnerabilities in SQL Server 2000 Resolution Service have been discovered which could allow attackers to inject malicious code. Resolution Service is also prone to a system-exhausting denial of service attack.

Microsoft has released a patch designed to address these three flaws, which it describes as critical. Credit for uncovering the bugs goes to David Litchfield of Next Generation Security Software.

Our old friend buffer overflow bugs also make a further appearance in Microsoft Exchange 5.5.

Internet Mail Connector (IMC) enables Microsoft Exchange Server to communicate with other mail servers via SMTP. It contains an unchecked buffer in the part of its code which deals with handshakes when connecting to SMTP server.

Microsoft recommends that users review its fix, which it describes as moderately important.

SQL Server 2000, Service Pack 2, has also become entangled in a buffer overflow bug. In this case, a buffer overrun flaw has been discovered in several Database Consistency Checkers (DBCCs) that ship as part of SQL Server 2000. There's a SQL injection vulnerability that occurs in two stored procedures used in database replication.

You can review the fix for these flaws, which are defined by Microsoft as moderately severe, here.

Next up there's an Authentication Flaw in Microsoft Metadirectory Services (MMS).

Specifically, it is possible for an unprivileged user to connect to the MMS data repository via an LDAP client in such a way as to bypass certain security checks.

This could enable an attacker to modify data within the MMS data repository, either for the purpose of changing the MMS configuration or replicating bogus data to the other data repositories.

Pulling this off would require a fair deal of knowledge, so its hardly s'kiddie stuff and attacks over the Internet should be blocked at a firewall. You can read more about this medium risk flaw here.

With all these fixes flying around it's only human for Microsoft to let one slip. For this reason, Microsoft has reissued a cumulative update for Media Player which, it admits, failed to include a fix for a flaw that dates back to last year. The patch it issued last month, to some controversy, contained a patch which combated three recently discovered critical vulnerabilities but didn't fix older bugs. ®