GANGRENE: Exploring the Mortality of Flash Memory

Flash memory is used for non-volatile storage in a vast array of devices that touch users at work, at home, and at play. Flash memory offers many desirable characteristics, but its key weakness is limited write endurance. Endurance limits continue to decrease as smaller integrated circuit architectures and greater storage densities are pursued. There is a significant body of published work demonstrating methods to extend flash endurance under normal use, but performance of these methods under malicious use has not been adequately researched.

We introduce GANGRENE, an attack to accelerate wear of flash devices to induce premature failure. By testing a sampling of flash drives, we show that wear can be accelerated by an order of magnitude. Our results offer evidence that vendor-provided endurance ratings, based on normal use, ignore this underlying vulnerability. Because of the high penetration of flash memory, the threat of such attacks deserves attention by vendors and researchers in the community. We propose recommendations and mitigations for GANGRENE and suggest future work to address such vulnerabilities.