The entire IO subsystem, from the filter drivers down to the disks. Corruption is 99% of the time an IO subsystem problem, could be anything in the stack. Check the logs, check the firmware versions, check the driver versions, etc.
If you don't own the IO subsystem, then you'll need to chat with whoever does.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability