  Semiconductor NAND Flash based memory technology dominates the electronic
Non-Volatile storage media market. Though NAND Flash offers superior
performance and reliability over conventional magnetic HDDs, yet it suffers
from certain data-security vulnerabilities. Such vulnerabilities can expose
sensitive information stored on the media to security risks. It is thus
necessary to study in detail the fundamental reasons behind data-security
vulnerabilities of NAND Flash for use in critical applications. In this paper,
the problem of unreliable data-deletion/sanitization in commercial NAND Flash
media is investigated along with the fundamental reasons leading to such
vulnerabilities. Exhaustive software based data recovery experiments (multiple
iterations) has been carried out on commercial NAND Flash storage media (8 GB
and 16 GB) for different types of filesystems (NTFS and FAT) and OS specific
delete/Erase instructions. 100 % data recovery is obtained for windows and
linux based delete/Erase commands. Inverse effect of performance enhancement
techniques like wear levelling, bad block management etc. is also observed with
the help of software based recovery experiments.
