  Ineffective Fault Analysis (SIFA) was introduced as a new approach to attack
block ciphers at CHES 2018. Since then, they have been proven to be a powerful
class of attacks, with an easy to achieve fault model. One of the main benefits
of SIFA is to overcome detection-based and infection-based countermeasures. In
this paper we explain how the principles of SIFA can be applied to GIMLI, an
authenticated encryption cipher participating the NIST-LWC competition. We
identified two possible rounds during the intialization phase of GIMLI to mount
our attack. If we attack the first location we are able to recover 3 bits of
the key uniquely and the parity of 8 key-bits organized in 3 sums using 180
ineffective faults per biased single intermediate bit. If we attack the second
location we are able to recover 15 bits of the key uniquely and the parity of
22 key-bits organized in 7 sums using 340 ineffective faults per biased
intermediate bit. Furthermore, we investigated the influence of the fault model
on the rate of ineffective faults in GIMLI. Finally, we verify the efficiency
of our attacks by means of simulation.
