There is provided a computer implemented method of generating a vaccination profile of malicious code for vaccination against other instances of the malicious code, comprising: providing malicious code, analyzing the malicious code to identify at least one vaccination artifact system call indicative of an attempt to identify malicious code executing on a client computing device prior to another instance of the malicious code infecting the client computing device, generating according to the analysis of the malicious code, a vaccination profile including the at least one vaccination artifact system call, and providing the vaccination profile to a plurality of client computing devices for vaccination of the plurality of client computing devices uninfected by the malicious code, wherein an existing infection by the malicious code is emulated based on the vaccination profile for prevention of infection of the plurality of computing devices by another instance of the malicious code.