The Phantom

During a particular development we had created a security system at the very beginning and it was thereafter included in every screen that was written. Of course, when it came to testing each screen it had to be set up on the security system, and with many screens coming up for testing every day this was a tedious job. As a shortcut a program was written which would add all the new screens together as it was run. And every time this program was run it displayed a different picture and message from the 'phantom'. We asked everyone in the team if they were the 'phantom' and everyone denied it, and so we checked the machine logs but it told us that the program had been amended on one of the testing terminals and we could not therefore pin the culprit down. In fact it took months of the phantom's appearances, and some detailed technical analysis before it became clear who was behind it.

As a footnote to the story of the 'phantom', the person who managed to make all those unauthorised changes to programs without getting caught eventually became a computer auditor - poachers becoming gamekeepers?