The Art of Security

Back in 1987, a colleague and I were using the large computer systems of the University of Leicester to run rather a lot of number crunching. Leicester had a large, well connected and well managed VAX Cluster which was ideal as a platform to collect password files and analyse them for erm… Statistics. It’s probably fair to say that we didn’t have permission to be using the Leicester systems but life was somewhat different then.

We’d been using this machine for a few months and one day we spotted that something was amiss. The Systems Manager of the machine had activated process accounting which effectively meant that everything we had done had been logged and there was a complete audit-trail of our naughtiness.

This was a long time ago, in the days before writeable CDs but we had an equally bad adversary in the guise of the system console of the VAX 8600 we were squatting on. In those days consoles looked like this:

We had a problem at this point, in that we didn’t really want the people at Leicester knowing what we’d been doing and at the same time we were somewhat stuck because it had all been printed out and you can’t remotely edit a teletypewriter trail. Although we’d turned off the accounting, and disabled any future accounting, we were in a little bit of a hole.

We pondered this for a while and came up with a nice and neat solution – We’d get the logs from the last week and we’d edit any traces of ourselves out – We’d then print this to the printer so that anybody looking back over it for however many days wouldn’t see us. A little bit of editing and a couple of hundred pages of printing later, we’d wiped all traces of our activity out. Taking the hint that we probably weren’t wanted, we politely left, breathing a small sigh of relief that we’d narrowly escaped detection.

A couple of years later, I was doing my postgraduate at Leicester University and I went for a drink with their Systems Manager, Pete Humble – I was a little more well known at this point as one of the “good guys” and we got to chatting about the old days and for some reason the subject of tracking a big hack a couple of years back came up. Pete told the story of how some people had been using his machines for nefarious activities but they’d always managed to evade any logging so nobody had a clue what they were doing.

Apparently he came up with the idea of setting process accounting on the miscreants and logging this all to the console. I grinned knowingly and smugly asked him how that went for him and was somewhat taken aback when he explained that those pesky kids had cleverly reprinted a few of days of sanitised logs to hide themselves BUT, that every night, he had marked the stack of paper on the edge with a thick red marker and when he saw that the evening had produced an extra foot or so of printout above the last red mark, he’d realised what had happened.

At that point, I bought the drinks for the rest of the evening and congratulated him on being the only person to have ever caught me, with something as apparently low tech as a red permanent marker pen.

Peet remained one of my best friends until he died a few years ago, and I like to think that he taught me a lot more than not to be too smug in underestimating lower-tech solutions.

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Amusement, Narrative by Michael