In the present article, the authors have studied the dynamical behavior of delay‐varying computer virus propagation (CVP) model with fractional order derivative, and it is found that the chaotic attractor exists in the considered fractional order system. In order to eliminate the chaotic behavior of fractional order delay‐varying CVP model, feedback controlmethod is used. This article also dealswith the synchronization between controlled and chaotic delay‐varying CVPmodel via active controlmethod. The fractional derivative is described in the Caputo sense. Numerical simulation results are carried out by means of Adams‐Boshforth‐Moultonmethod with the help ofMATLAB, and the results are successfully depicted through graphs .Copyright © 2015 John Wiley & Sons, Ltd.