Microsoft Warns of SQL Server Flaws

The company also issues security bulletins warning of problems in Exchange 5.5 and Metadirectory Services 2.2.

Microsoft Corp. on Wednesday unleashed a flurry of security bulletins warning of problems in several of its products, including SQL Server 2000, Exchange 5.5 and Metadirectory Services 2.2.

The most serious of the vulnerabilities are two buffer overruns in SQL Server 2000. Both of these problems enable an attacker to completely compromise a target server and its data without authenticating to the server.

The application has functionality that allows multiple instances of SQL Server 2000 to run on a single machine at a given time. The default TCP listening port for the program is 1433, which can only be used by one instance. Other instances will listen on whatever port is assigned to them by the Resolution Service.

By sending a carefully crafted packet to the Resolution Service on UDP port 1434, an attacker could overwrite either a portion of the heap or the stack memory, depending on the contents of the packet. If the attacker sends carefully chosen data in his packets, he will gain complete control of the server, according to Microsofts bulletin.

There is also a buffer overrun vulnerability in several of the Database Consistency Checkers that ship with SQL Server 2000. These utilities, which are used for maintenance on the server, are typically only executable by users logged in as sysadmin. However, some are executable by other users, and an exploitation of the buffer overrun in these utilities gives an attacker the ability to run arbitrary code on the server.

In addition, Microsoft disclosed a SQL injection vulnerability in two stored procedures in SQL Server 2000 that under a narrow set of circumstances could allow an attacker to run operating system commands on the server.

In addition to the SQL problems, Microsoft, of Redmond, Wash., issued an advisory and patch for a buffer overrun in the Internet Mail Connector (IMC) in Exchange 5.5. The flaw lies in the way the server responds to "extended Hello" SMTP messages from other servers. Under certain conditions, an attacker could overflow a buffer in the IMC, giving him the ability to execute code on the server. But, because the attacker cannot simply send his own data to the server and overflow the vulnerable buffer, the attack requires quite a bit of work to execute, Microsoft said.

There is also a flaw in Microsoft Metadirectory Services that allows an unprivileged user to connect to the MMS data repository through an LDAP client, which would bypass some security checks. The user could then manipulate data within the repository.

Microsoft also issued a revised cumulative patch for Windows Media Player 6.4, 7.1 and XP. The original patch, released in June, was missing a file containing the fixes for all of the previous flaws in the software; it only contained the patch for three flaws discovered in June.

The various bulletins and patches are available here.

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