Summary

UNIX systems present an ostensibly clean and simple interface for privilege management and file manipulation. Closer inspection, however, reveals many subtle nuances that can conspire to make things difficult for security-conscious developers. At the end of the day, it's not easy to create totally bug-free secure code, especially when you're trying to make applications portable across a number of different UNIX systems. You have explored myriad problems that can occur in file and privilege code and auditing techniques that should equip you to audit security-sensitive UNIX applications.