This study tested whether the presence of a surveillance message on an attacked computer system influences system trespassers’ active engagement with the compromised system (i.e., entering computer commands).
The hypothesized restrictive deterrent effect was tested both in the context of a first system trespassing incident and in the progression of repeated trespassing incidents in an attacked computer system. A randomized controlled trial was designed and deployed in a series of virtual target computers with known vulnerabilities into the computer network of a large public university in the United States. The target computers were set to either display or not display a surveillance banner once system trespassers infiltrated them. The study found that the presence of a surveillance banner in the attacked computer systems reduced the probability of commands being typed in the system during longer first system trespassing incidents. Further, findings indicate that the probability of commands being typed during subsequent system trespassing incidents (on the same target computer) was conditioned by the presence of a surveillance banner and by whether commands had been entered during previous trespassing incidents. These findings offer modest support for the application of restrictive deterrence in the prevention of system trespassing. (publisher abstract modified)