Malware is (potentially) well written software, indistinguishable from any other piece of code, until if performs a malicious act. Malware should not automatically be considered good as malware, until such time as its intent can be proven to be good now and through any future event. The more advanced detection systems will be able to identify known malware even when its disguised, but the key is detection systems rely on already knowing a file is bad. Even when users are coerced to engage with malware through social engineering techniques this model will still stop infections.”]
Source: https://hackercombat.com/knowledge-base/what-is-malware/