This indicates a possible attempt to exploit a buffer-overflow vulnerability in Microsoft SQL Server.
The vulnerability is caused by the SQL Server's insufficient validation of the input arguments provided to the convert( ) function. It allows a remote attacker to execute arbitrary code by sending a specially crafted SQL expression.
SQL Server 2000 SP4
SQL Server 2000 x64-based Edition SP4
SQL Server 2000 Itanium-based Edition SP4
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the vendor's web site for the suggested workaround: