Glitch It If You Can: Parameter Search Strategies for Successful Fault Injection

Abstract

Fault analysis poses a serious threat to embedded security devices, especially smart cards. In particular, modeling faults and finding effective practical approaches that are also generic is considered to be of interest for smart card industry. In this work we propose a novel methodology to deal with a difficult question of choosing multiple parameters required for effective faults. To this aim, we investigate several algorithms and find a new promising direction using evolutionary computation. Our experimental results on some of the smart cards used today show the potential of this new approach. Our best algorithm is a tailored search strategy especially developed for the purpose of finding the best choice of parameters for glitching. With this approach we found some of off-the-shelf devices, although secured against this type of attacks, still vulnerable.

Appendix: TOE Details

A more detailed description of the TOEs described in this paper follows:

Target A: It is a smartcard based on an ATMega163+24C256 IC, CMOS technology, hardware last revision 2003. This TOE does not have any side-channel countermeasure nor fault-injection countermeasure. All processing of the card is performed in software, and the card was running on an external 4 MHz clock frequency. In particular, this target is also available from Riscure BV as the research target “Training Card 6”. The code that was attacked was a vulnerable PIN (Personal Identification Number) authentication mechanism is as follows:

Target B: It is a smartcard bought in 2013 from a webshop from one of the leading manufacturers in the sector. This TOE is a protected target, and has countermeasures against SCA and FI, such as fault injection detection logic and light, temperature and clock sensors. The IC design is from late 2004. Additionally, it has dedicated logic for cryptographic operations. More in detail, this TOE implements the JavaCard OS 2.2.1 and GlobalPlatform 2.1.1 standard. It runs on an internal, unstable clock at an unknown frequency. The supplied external clock frequency was 4 MHz. The card was running exclusively on software (no crypto hardware present in the IC was used). The Java applet loaded into the card was a double nested loop with two counters and a checksum. The code was similar to the following piece of code:

Target C: It is a smartcard bought in 2013 from a webshop from one of the leading manufacturers in the sector. This TOE is a protected target, and has the same feature set as Target B in terms of hardware and countermeasures. This TOE implements the JavaCard OS 2.2.1 and GlobalPlatform 2.1 standard. It was also Common Criteria certified level EAL4+ in 2008. The Java applet loaded into the card was the same applet as described for Target B.