1. A method of detecting unauthorized executable programs resident in a computer system memory comprising the steps of: a) receiving a trusted hash value representative of a hash value for generation by a predetermined hashing process of predetermined data stored in memory within the computer system if an unauthorized executable program is other than resident in the computer system; b) hashing the data stored in memory within the computer system using the predetermined hashing process to determine a computed hash value; and c) comparing the computed hash value and the trusted hash value to determine differences between the data and the predetermined data.