This paper provides an analysis of the impact of attacks on the Age of Information (AoI) in queuing systems. We consider single and tandem queue models, with and without preemption in service. We have shown that when preemption in service is allowed, attacks do not result in AoI reduction. For non preemptive servers, we show that attacks can reduce the AoI for both tandem and single server cases. For the single server case, we establish necessary and sufficient conditions for the existence of arrival and attacks rates that minimize the AoI and provide an explicit expression of the optimal attack rate when the arrival rate of updates is very large. Numerical results corroborate the analytical claims and show the accuracy of the obtained results when the arrival rate of update is low.