A cikin yanayin da polymorphic ƙwayoyin cuta, duk da haka, wannan decryption module ne kuma modified a kan kowane kamuwa da cuta. A da kyau rubuta polymorphic cutar sabili da haka ba shi da sassa da suka kasance daidai tsakanin kamuwa da cuta, sa shi sosai wuya a gane kai tsaye ta amfani da "alamar". Antivirus software iya gane shi da decrypting da ƙwayoyin cuta ta amfani da wani emulator, ko ta hanyar ilimin kididdiga na encrypted cutar jiki. Don ba da damar polymorphic cutar yana da a mutalphic engine (da ake kira "mutating engine" ko "mutation engine") inda za a iya samun damar yin amfani da irin wannan polymorphic code ko kuma alamu na cutar da za su iya zama m a kan wani lokaci. Wannan tambaya tana bukatar wani abu mai mahimmanci a lokacin da masu amfani da software na rigakafi za su iya yin bincike a hankali ko kuma a hankali don gano ƙwayoyin cuta ta hanyar yin amfani da ƙirar ƙwayoyin cuta. Wannan yana da wuya a gano ƙwayoyin cuta saboda ƙwayoyin cuta
suna da injin polymorphic