Hex editor works.
Pick a page you want to corrupt, identify an allocated page using DBCC IND for a table and cacluate the offset as (page Number)*8192 bytes
Take the DB offline, open the data file in a hex editor (HxD is good), go to the offset calculated, write garbage over a few bytes, save, exit
Bring the DB back online.
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