Family (malware family) is a classification unit for detectable objects that share common attributes. Typically, a malware family groups together various versions and variations of the same software, such as malware, adware, etc. Additionally, objects with a common origin (authorship, source code), behavior, algorithms, working principles, or applied packing or obfuscation algorithms may also be grouped into one family. For instance, Trojan.Win32.StartPage is a family of malware that modifies browser home pages.
The list of families is constantly updated and expanded. As of 2025, Kaspersky’s collection comprises over 46,000 identified families.