Microsoft is aware of a recent escalation in a class of attacks targeting Web sites that use Microsoft ASP and ASP.NET technologies but do not follow best practices for secure Web application development. These SQL injection attacks do not exploit a specific software vulnerability, but instead target Web sites that do not follow secure coding practices for accessing and manipulating data stored in a relational database. When a SQL injection attack succeeds, an attacker can compromise data stored in these databases and possibly execute remote code. Clients browsing to a compromised server could be forwarded unknowingly to malicious sites that may install malware on the client machine.
This vulnerability is not exploitable in Web applications that follow generally accepted best practices for secure Web application development by verifying user data input.
Reference : Pinal Dave (http://blog.SQLAuthority.com)