The problem of tracking the expected market demand and suppressing the bullwhip effect was investigated for an unknown nonlinear supply chain systems (SCS) subject to a denial-of-service (DoS) attack on the commodity output. The supply chain system was first transformed into a dynamic data model using a dynamic linearisation approach. Then, considering that the DoS attack followed a Bernoulli distribution and occured randomly in the transmission channel between the sensor and the control centre, the lost commodity output due to the DoS attack was replaced by the estimated value of the historical data at the previous moment. The model-free adaptive defensive control algorithm was then designed based on the raw material orders and commodity output of each subchain under the DoS attack, and the convergence of the closed-loop system under the defensive control algorithm was demonstrated by theoretical analysis. Finally, the effectiveness of the defensive control algorithm was verified by simulation.