Disclosed herein are systems and methods of creating antivirus records. An exemplary method comprises: analyzing, by a protector against targeted attacks, a log of API function calls of a file for presence of malicious behavior using one or more behavioral rules; determining that the file is malicious when a behavioral rule corresponding to records of a log of API function calls is identified; extracting one or more records of API function calls associated with the identified behavioral rule; determining whether at least one extracted record of the API function calls can be registered by a protector of a computing device; and when the at least one extracted record can be registered by the protector of the computing device, creating an antivirus record for the protector of the computing device, wherein the created antivirus record includes at least the extracted records of the API function calls.