Syracuse University
Set-UID Lab
Overview
Set-UID is an important security mechanism in Unix operating systems. When a Set-UID program is run, it assumes the owner's privileges. For example, if the program's owner is root, then when anyone runs this program, the program gains the root's privileges during its execution. Set-UID allows us to do many interesting things, but unfortunately, it is also the culprit of many bad things. Therefore, the objective of this lab is two-fold: (1) Appreciate its good side: understand why Set-UID is needed and how it is implemented. (2) Be aware of its bad side: understand its potential security problems.Lab Description and Tasks (pdf)
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For instructors: if you prefer to modify the lab description
to suit your own courses, you can download the source files (Latex)
from here.
Time for This Lab: 2 weeks
Helpful Documents
- How system call invocation works: we use chmod command as an example to illustrate the control flow of a system call invocation in Minix.
- Checklist for Security of Setuid Programs
- Chen, Wagner, and Dean. Setuid Demystified
- Bishop. How to write a Set-UID program
Survey
The following survey is designed to help us understand how effectively this lab has enhanced students' learning in computer security. The survey is anonymous, and is usually conducted after students finish the lab.Updated on 2/1/2007