Gathering information about the file system is the primary method of black box security audits. The classical method of this attack is dirbusting - brute force files and directories full names to obtain their contents. In this paper author consider new methods of attack, based on timings, which can significantly reduce the time to observing files and directories. Classic divergent bruteforce problems are reduced to convergent analogue of search. Timing techniques are investigated for both hardware and for software. Also, the author researched overall theory of such effects.